WO2015152554A1

WO2015152554A1 - Method for controlling secondary cell operation of terminal, and apparatus therefor

Info

Publication number: WO2015152554A1
Application number: PCT/KR2015/002852
Authority: WO
Inventors: 홍성표; 최우진
Original assignee: 주식회사 케이티
Priority date: 2014-04-01
Filing date: 2015-03-24
Publication date: 2015-10-08

Abstract

The present invention relates to a method for controlling secondary cell operation of a terminal, and an apparatus therefor. In particular, the present invention relates to a method and an apparatus for controlling secondary cell operation by a terminal, the method comprising the steps of: receiving measurement configuration information for measuring a cell discovery signal; transmitting measurement information of a cell measured on the basis of the measurement configuration information and the cell discovery signal; and further configuring, as a secondary cell, a cell associated with the cell discovery signal on the basis of an upper layer signal.

Description

Secondary cell operation control method and terminal thereof

The present invention relates to a method and apparatus for controlling a secondary cell operation of a terminal. More specifically, a method in which a terminal adding a cell supporting an on / off function as a secondary cell controls a secondary cell activation or deactivation operation of a terminal according to on / off indication information on a corresponding secondary cell received from a base station. And to an apparatus.

As communication systems have evolved, consumers, such as businesses and individuals, have used a wide variety of wireless terminals. Mobile communication systems such as LTE (Long Term Evolution) and LTE-Advanced of the current 3GPP series are high-speed and large-capacity communication systems that can transmit and receive various data such as video and wireless data beyond voice-oriented services. The development of technology capable of transferring large amounts of data is required. As a method for transmitting a large amount of data, data can be efficiently transmitted using a plurality of cells.

In this situation, in order to transmit a large amount of data at high speed and to reliably transmit and receive data in an environment in which a large number of terminals are concentrated in a specific base station, a technique of deploying a large number of small base stations having a relatively narrow coverage such as a small cell is discussed. There is a situation. In such an environment in which a small base station is deployed, the terminal may improve data processing speed by transmitting and receiving data and signals using a macro base station having a relatively wide coverage with the small base station.

However, in the small base station, since the coverage is relatively narrow, there may be a case in which the terminal does not exist in a small cell at a specific time or a specific location. Alternatively, a case in which a small cell is not used may occur according to a data processing need of the terminal. Even in this case, operating a small cell has a problem of causing a waste of power consumption as a whole of the system.

In addition, in an environment in which a large number of small cells are deployed, a problem may occur in that signal interference between the cells increases due to an increase in a reference signal.

In addition, when a small cell uses an unlicensed band, always operating a small cell using an unlicensed band violates the regulations of countries that restrict continuous transmission.

The present invention devised to solve the above-described problem proposes a specific operation method and apparatus for adding a cell supporting the on / off function as a secondary cell in a small cell deployment environment.

The present invention also provides a method and apparatus for controlling a secondary cell activation or deactivation operation of a terminal according to on / off indication information received from a base station when the terminal adds a cell supporting an on / off function. Suggest.

According to an aspect of the present invention, there is provided a method of controlling a secondary cell operation by a terminal, the method comprising receiving measurement configuration information for measuring a cell discovery signal, and measuring a cell based on the measurement configuration information and the cell discovery signal And transmitting the measurement information of the cell and additionally configuring the cell associated with the cell discovery signal as the secondary cell based on the higher layer signal.

In addition, the present invention provides a method for a base station to control the operation of the secondary cell of the terminal, the measurement configuration information for measuring the cell discovery signal and the measurement information of the cell associated with the cell discovery signal measured based on the cell discovery signal And transmitting a higher layer signal including information for controlling the terminal to further configure a cell associated with the cell discovery signal as a secondary cell.

In addition, the present invention provides a terminal for controlling the operation of the secondary cell, the receiving unit for receiving the measurement configuration information for measuring the cell discovery signal and the transmission unit for transmitting the measurement information of the cell measured based on the measurement configuration information and the cell discovery signal And a controller configured to additionally configure a cell associated with the cell discovery signal as a secondary cell based on the higher layer signal.

In addition, the present invention provides a base station for controlling the operation of the secondary cell of the terminal,

Measurement configuration information for measuring a cell discovery signal and a receiver for receiving measurement information of a cell associated with a cell discovery signal measured based on the cell discovery signal, and information for controlling the terminal to additionally configure a cell associated with the cell discovery signal as a secondary cell. It provides a base station apparatus including a transmitter for transmitting a higher layer signal comprising a.

As described above, the present invention provides an effect of preventing signal interference between cells and wasting of power of the entire system by adding a cell supporting an on / off function as a secondary cell in an environment in which a plurality of small cells are deployed.

In addition, the present invention defines a method of operating the secondary cell of the terminal according to the on / off indication information of the base station when the terminal adds a cell supporting the on / off function to turn on / off of the cell supporting the on / off function It provides an effect of preventing ambiguity about the secondary cell activation operation of the terminal according to the indication information.

In addition, the present invention provides a specific method for transmitting and receiving data as needed in parallel with the on / off function and the activation operation provides an effect of processing a large amount of data at high speed.

In addition, when the unlicensed band cell is configured as a secondary cell, the present invention provides an effect of distinguishing and processing channel occupied time by an unlicensed band cell through a cell on / off function.

1 is a view for explaining a method of informing the on-off state of a secondary cell according to an embodiment of the present invention.

2 is a view for explaining a method of notifying the on-off state of a secondary cell according to another embodiment of the present invention.

3 is a view for explaining a method of notifying the on-off state of a secondary cell according to another embodiment of the present invention.

4 is a view for explaining the operation of the terminal and the base station according to another embodiment of the present invention.

5 is a flowchart illustrating a terminal operation according to another embodiment of the present invention.

6 is a flowchart illustrating an operation of a terminal receiving a physical layer signal according to another embodiment of the present invention.

7 is a flowchart illustrating the operation of another base station according to another embodiment of the present invention.

8 is a flowchart illustrating an operation of a base station for transmitting a physical layer signal according to another embodiment of the present invention.

9 is a diagram illustrating a terminal configuration according to another embodiment of the present invention.

10 is a diagram illustrating a configuration of a base station according to another embodiment of the present invention.

Hereinafter, some embodiments of the present invention will be described in detail through exemplary drawings. In adding reference numerals to the components of each drawing, it should be noted that the same reference numerals are assigned to the same components as much as possible even though they are shown in different drawings. In addition, in describing the present invention, when it is determined that the detailed description of the related well-known configuration or function may obscure the gist of the present invention, the detailed description thereof will be omitted.

The wireless communication system in the present invention is widely deployed to provide various communication services such as voice, packet data, and the like. The wireless communication system includes a user equipment (UE) and a base station (base station, BS, or eNB). In the present specification, a user terminal is a generic concept meaning a terminal in wireless communication. In addition, user equipment (UE) in WCDMA, LTE, and HSPA, as well as mobile station (MS) in GSM, user terminal (UT), and SS It should be interpreted as a concept that includes a subscriber station, a wireless device, and the like.

A base station or a cell generally refers to a station that communicates with a user terminal, and includes a Node-B, an evolved Node-B, an Sector, a Site, and a BTS. Other terms such as a base transceiver system, an access point, a relay node, a remote radio head (RRH), a radio unit (RU), and a small cell may be called.

In other words, in the present specification, a base station or a cell is a generic meaning indicating some areas or functions covered by a base station controller (BSC) in CDMA, a Node-B in WCDMA, an eNB or a sector (site) in LTE, and the like. It should be interpreted as, and it is meant to cover all the various coverage areas such as megacell, macrocell, microcell, picocell, femtocell and relay node, RRH, RU, small cell communication range.

Since the various cells listed above have a base station for controlling each cell, the base station may be interpreted in two senses. i) the device providing the megacell, the macrocell, the microcell, the picocell, the femtocell, the small cell in relation to the wireless area, or ii) the wireless area itself. In i) all devices which provide a given wireless area are controlled by the same entity or interact with each other to cooperatively configure the wireless area to direct the base station. The eNB, RRH, antenna, RU, LPN, point, transmit / receive point, transmit point, receive point, and the like, according to the configuration of the radio region, become an embodiment of the base station. In ii), the base station may indicate the radio area itself to receive or transmit a signal from the viewpoint of the user terminal or the position of a neighboring base station.

Therefore, megacells, macrocells, microcells, picocells, femtocells, small cells, RRHs, antennas, RUs, low power nodes (LPNs), points, eNBs, transmit / receive points, transmit points, and receive points are collectively referred to as base stations. do.

In the present specification, the user terminal and the base station are two transmitting and receiving entities used to implement the technology or technical idea described in this specification in a comprehensive sense and are not limited by the terms or words specifically referred to. The user terminal and the base station are two types of uplink or downlink transmitting / receiving subjects used to implement the technology or the technical idea described in the present invention, and are used in a generic sense and are not limited by the terms or words specifically referred to. Here, the uplink (Uplink, UL, or uplink) refers to a method for transmitting and receiving data to the base station by the user terminal, the downlink (Downlink, DL, or downlink) means to transmit and receive data to the user terminal by the base station It means the way.

There is no limitation on the multiple access scheme applied to the wireless communication system. Various multiple access techniques such as Code Division Multiple Access (CDMA), Time Division Multiple Access (TDMA), Frequency Division Multiple Access (FDMA), Orthogonal Frequency Division Multiple Access (OFDMA), OFDM-FDMA, OFDM-TDMA, OFDM-CDMA Can be used. One embodiment of the present invention can be applied to resource allocation in the fields of asynchronous wireless communication evolving to LTE and LTE-Advanced through GSM, WCDMA, HSPA, and synchronous wireless communication evolving to CDMA, CDMA-2000 and UMB. The present invention should not be construed as being limited or limited to a specific wireless communication field, but should be construed as including all technical fields to which the spirit of the present invention can be applied.

The uplink transmission and the downlink transmission may use a time division duplex (TDD) scheme that is transmitted using different times, or may use a frequency division duplex (FDD) scheme that is transmitted using different frequencies.

In addition, in systems such as LTE and LTE-Advanced, a standard is configured by configuring uplink and downlink based on one carrier or a pair of carriers. The uplink and the downlink include a Physical Downlink Control CHannel (PDCCH), a Physical Control Format Indicator CHannel (PCFICH), a Physical Hybrid ARQ Indicator CHannel (PHICH), a Physical Uplink Control CHannel (PUCCH), an Enhanced Physical Downlink Control CHannel (EPDCCH), and the like. Control information is transmitted through the same control channel, and data is configured by a data channel such as a physical downlink shared channel (PDSCH) and a physical uplink shared channel (PUSCH).

On the other hand, control information may also be transmitted using an enhanced PDCCH (EPDCCH or extended PDCCH).

In the present specification, a cell means a component carrier having a coverage of a signal transmitted from a transmission / reception point or a signal transmitted from a transmission point or a transmission / reception point, and the transmission / reception point itself. Can be.

A wireless communication system to which embodiments are applied may be a coordinated multi-point transmission / reception system (CoMP system) or a coordinated multi-antenna transmission scheme in which two or more transmission / reception points cooperate to transmit a signal. antenna transmission system), a cooperative multi-cell communication system. The CoMP system may include at least two multiple transmission / reception points and terminals.

The multiple transmit / receive point is at least one having a base station or a macro cell (hereinafter referred to as an eNB) and a high transmission power or a low transmission power in a macro cell region, which is wired controlled by an optical cable or an optical fiber to the eNB. May be RRH.

In the following, downlink refers to a communication or communication path from a multiple transmission / reception point to a terminal, and uplink refers to a communication or communication path from a terminal to multiple transmission / reception points. In downlink, a transmitter may be part of multiple transmission / reception points, and a receiver may be part of a terminal. In uplink, a transmitter may be part of a terminal, and a receiver may be part of multiple transmission / reception points.

Hereinafter, a situation in which a signal is transmitted and received through a channel such as a PUCCH, a PUSCH, a PDCCH, an EPDCCH, and a PDSCH may be expressed in the form of 'sending and receiving a PUCCH, a PUSCH, a PDCCH, an EPDCCH, and a PDSCH.'

In addition, hereinafter, a description of transmitting or receiving a PDCCH or transmitting or receiving a signal through the PDCCH may be used as a meaning including transmitting or receiving an EPDCCH or transmitting or receiving a signal through the EPDCCH.

That is, the physical downlink control channel described below may mean PDCCH or EPDCCH, and may also be used to include both PDCCH and EPDCCH.

In addition, for convenience of description, the EPDCCH, which is an embodiment of the present invention, may be applied to the portion described as the PDCCH, and the EPDCCH may be applied to the portion described as the EPDCCH as an embodiment of the present invention.

Meanwhile, high layer signaling described below includes RRC signaling for transmitting RRC information including an RRC parameter.

The eNB performs downlink transmission to the terminals. The eNB includes downlink control information and an uplink data channel (eg, a physical downlink shared channel (PDSCH), which is a primary physical channel for unicast transmission, and scheduling required to receive the PDSCH. For example, a physical downlink control channel (PDCCH) for transmitting scheduling grant information for transmission on a physical uplink shared channel (PUSCH) may be transmitted. Hereinafter, the transmission and reception of signals through each channel will be described in the form of transmission and reception of the corresponding channel.

In the present specification, a small cell means a cell having a narrower coverage than a macro cell, and the small cell may be provided by any communication device that provides communication coverage, such as a base station or a wireless router. In addition, hereinafter, the small cell may refer to a communication device itself that provides coverage such as a base station or a wireless router.

셀 활성화/비활성화(activation/deactivation)Cell activation / deactivation

In a single base station-based carrier aggregation (CA) technology or multiple base station-based dual connectivity technology, the small cell may be configured as an additional serving cell or a secondary cell. When the small cell is configured as an additional serving cell or secondary cell in the terminal, an RRC connection reconfiguration procedure may be used. When the small cell is configured by the base station as an additional serving cell or secondary cell in the terminal, the terminal configures the additional serving cell or secondary cell in the lower layer to be considered inactive (UE configure lower layers to consider the SCell to be in deactivated state). In the case of dual connectivity, the small cell may be configured as a secondary cell rather than a primary secondary cell. In the following description, the secondary cell is described as meaning that the small cell includes all of the secondary cells other than the primary secondary cell in the case of an additional serving cell, secondary cell, or dual connectivity.

Therefore, in order to use the DL Component Carrier and / or UL Component Carrier of the secondary cell, the additionally configured secondary cell must be activated. That is, for efficient battery management of the terminal, the terminal requires an operation of an activation step that is different from the secondary cell addition or secondary base station addition step for additionally configuring the secondary cell.

Activation and deactivation of the secondary cell is performed through a medium access control (MAC) signal. The UE may perform only Reference Signal Received Power (RSRP) or Reference Signal Received Quality (RSRQ) measurement on the deactivated secondary cell without performing Channel State Information (CSI) measurement. Through this, by blocking the CSI measurement that requires a lot of power consumption, it is possible to efficiently manage the power consumption of the terminal. For the secondary cell in an inactive state, transmission for an uplink component carrier is also disabled. Since the base station does not schedule the PUSCH for the deactivated secondary cell, it does not transmit a SRS (Sounding Reference Signal) to the cell.

As such, when the secondary cell is deactivated, the UE does not transmit the SRS to the secondary cell (not transmit SRS on the SCell) and does not transmit to the secondary cell UL-SCH (not transmit on UL-SCH on the SCell). Not transmit on RACH on the SCell, not CQI (channel quality indicator) / Precoding Matrix Indicator (PMI) / Rank Indicator (RI) / Progress Transaction Identifier (PTI) report for the secondary cell Do not perform (not report CQI / PMI / RI / PTI for the SCell), do not monitor the secondary cell (not monitor the PDCCH on the SCell), and do not perform PDCCH monitoring for the secondary cell (not monitor the PDCCH for the SCell).

When the secondary cell is activated, normal secondary cell operations (SRS transmissions on the SCell, CQI / PMI / RI / PTI reporting for the SCell, PDCCH monitoring on the SCell, PDCCH monitoring for the SCell) are performed. For example, when the secondary cell is activated, the UE transmits the SRS to the secondary cell, transmits the CQI / PMI / RI / PTI to the secondary cell, monitors the PDCCH in the secondary cell, and performs PDCCH monitoring for the secondary cell. can do.

스몰 셀 온/오프(On/Off)Small Cell On / Off

When multiple small cells are introduced overlapping with macro cell coverage, overall system throughput is increased through cell splitting gain, but inter-cell interference and power consumption are also increased. On the other hand, even when there is no terminal connected within the small cell coverage, the small cell must continuously transmit a downlink signal including PSS / SSS, PBCH or CRS, unnecessary power consumption and interference may occur.

In order to prevent such a situation, the state of the small cell can be changed dynamically. That is, the state of the small cell can be changed to the on state or the off state.

Small cell on / off may be performed for coordination and avoidance between cells, load balancing, energy saving, and the like. In particular, it is necessary to perform small cell on / off in a dense small cell deployment.

When the small cell is turned on, the small cell may transmit signals necessary for the terminal to receive data. For example, the small cell in the on state may transmit signals (eg, CRS, SI, etc.) transmitted from the existing cell in the same manner.

When the small cell is turned off, the small cell may not transmit signals necessary for the terminal to receive data. For example, the small cell in the off state does not transmit some or all of the signals (eg, CRS, SI, etc.) transmitted from the existing cell. However, even when the small cell is off, a discovery signal (for example, discovery reference signals (DRS)) signal for detecting the small cell may be transmitted. The discovery signal may be used to detect the presence of an off state cell, and the discovery signal may be used to measure the radio quality of the off state cell. The discovery signal may be referred to as a cell discovery signal. The cell discovery signal indicated in the present invention is not limited to 3GPP Rel-12 DRS. For example, it may include a signal for detecting a cell that supports any on / off function.

비면허 대역 셀(unlicensed band cell)Unlicensed band cell

In 3GPP, as a way to cope with the explosion of mobile data traffic, the necessity of a technical discussion to add and use an unlicensed frequency band cell as a secondary cell with the support of a licensed band cell is proposed. Unlicensed bands are regulated for fair use by heterogeneous networks or heterogeneous carriers, such as wireless local area networks (WLANs). For example, in Europe and Japan, continuous transmission is prohibited and the maximum duration of transmission burst is limited. For example, according to European regulations, the maximum channel occupancy should not exceed 13 ms. According to Japanese regulations, the maximum channel occupancy should not exceed 4ms.

As such, the unlicensed band cell has a limit on the maximum channel occupancy period, and should not occupy the channel for a predetermined time thereafter. It may be desirable to use the cell in an off state during periods that the channel cannot occupy. In addition, the cell may be used in an on state during the period in which the channel may be occupied. That is, for the unlicensed band cell, the base station may operate in a period in which the base station can occupy the channel of the unlicensed band cell in an off state.

The small cell on / off state described above may be determined according to information such as traffic load, user arrival / departure, packet arrival / completion, and maximum channel occupancy period regulation of an unlicensed band cell.

In order to determine a small cell on / off state, a UE in an RRC connected state may perform RRM measurement based on a cell discovery signal and report it to a base station.

However, unlike cell-specific reference signals (CRS) transmitted every subframe, the DRS transmitted through the small cell in the off state may be transmitted only within a limited subframe. Therefore, when the terminal uses the existing CRS-based RRM measurement method as it is, there is a problem in the terminal performs the RRM measurement based on the DRS and reporting it. That is, since the conventional RRM measurement is performed based on the CRS transmitted every subframe, there is a problem that the RRM measurement cannot be performed based on the DRS of the off state small cell transmitted only within the limited subframe.

On the other hand, according to the 3GPP TR 36.872 document, when the small cell on / off transition time is short, the user throughput gain can be obtained from the small cell on / off operation.

One way to reduce the transition time between on and off states is to define a new L1 procedure. The new L1 procedure can reduce interference in the network by allowing some subframes without downlink data transmission to be dynamically turned off in cells that support the on / off function.

However, the specific method of the new L1 procedure for reducing the small cell on / off transition time is not currently determined. Therefore, a small cell capable of providing an on / off function through the L1 procedure may not be added as a secondary cell, or the secondary cell may be activated to transmit data. In particular, in a state in which the secondary cell supporting the small cell on / off is activated, there is a problem that the terminal may perform an operation in an activated state even when the small cell is in the off state. In addition, even when the secondary cell is deactivated, even when the small cell is changed to the on state, there is a problem in that data cannot be transmitted quickly due to the deactivated terminal operation.

The present invention devised to solve this problem is to provide a method for the UE to efficiently perform the RRM measurement and report it to the base station based on the DRS of the off-state small cell transmitted only within a limited subframe. . In addition, when a UE and a base station transmit data by adding or activating a small cell supporting the on / off function as a secondary cell, the UE can effectively transmit and receive data through an L1 procedure that reduces the small cell on / off transition time. The purpose is to provide a way.

Specifically, operations of the small cell and the UE will be described as follows.

When the small cell is turned off, the small cell may transmit a cell discovery signal. The cell discovery signal may include a plurality of signals for coarse synchronization, cell identification, RRM measurement, and the like.

The UE may perform cell discovery signal based RRM measurement for intra-freq / inter-freq for small cell discovery (or small cell on / off determination, etc.) for transmitting the cell discovery signal.

One or more signals of PSS, SSS, CRS, CSI-RS, and PRS may be used for cell discovery in the cell discovery signal. In addition, one or more signals of PSS / SSS, CRS, CSI-RS, and PRS may be transmitted for small cell RSRP measurement. Alternatively, information necessary to perform small cell discovery may be provided to the terminal. This information may include at least timing related information of the discovery signal.

For small cell RRM measurement, DRS-based RSRP needs to provide RSRP measurement performance comparable to conventional CRS-based RSRP. Accordingly, the UE may receive a signal including at least one of a period, an offset, and potentially a duration of the cell discovery signal.

As an example of a procedure for small cell on / off state transition, a handover procedure, a secondary cell activation / deactivation procedure in a single base station based carrier aggregation (CA) technology, a secondary base station addition procedure or a secondary base station in a dual connectivity technology One or more of the secondary cell activation / deactivation procedures may be used.

As another example of a procedure for small cell on / off state transition, a new L1 procedure may be used that reduces the on / off transition time. The new L1 procedure is described in detail with reference to the drawings below.

Referring to FIG. 1, information indicating a secondary cell on / off state may be provided at a predetermined radio frame (or subframe) interval for a secondary cell through a primary cell (PCell). The UE can know the on / off state of the small cell through this.

For example, FIG. 1 illustrates the transmission of information explicitly indicating a secondary cell on / off state in a PCell in a fourth subframe before a start subframe of a radio frame at a radio frame interval. That is, the secondary cell SCell may perform the transition between the on state and the off state in units of radio frames. To this end, the terminal may receive the indication information 100 indicating the off state in the PCell. When the UE receives the subframe 100 including the indication information indicating the off state in the PCell, the SCell after 4 subframes may know that the OFF state. Similarly, the terminal may receive the indication information indicating the on state in the subframe 110 before the fourth, and may know that the next radio frame is in the on state. Thereafter, when the state of the secondary cell changes again, the terminal may receive indication information indicating an off state through the fourth subframe 120.

In FIG. 1, a state in which a small cell configured as a secondary cell is changed in units of radio frames is described as an example, but is not limited thereto. In addition, although FIG. 1 illustrates an example of receiving the state information of the small cell through the fourth subframe of the subframe in which the radio frame starts, this is for understanding and is not limited to the fourth. The subframe in which the state information of the small cell is received may be configured in the terminal through the base station or may be a value previously set in the terminal.

Referring to FIG. 2, when the state of the small cell is changed on a subframe basis as another example of the above-described L1 procedure, information indicating the change may be received. That is, the terminal may receive on / off state information of the secondary cell changed in units of subframes through the PCell. In this case, the terminal may also receive information on the number of subframes maintaining the state.

For example, the terminal may receive the corresponding state change information through the subframe of the second previous PCell of the subframe in which the state of the secondary cell changes. In detail, when the small cell configured as the secondary cell is changed from the off state to the on state, corresponding change information may be received through the

subframes

200 and 210 before the second subframe of the secondary cell which is changed to the terminal on state. .

Alternatively, state information may be received in units of subframes in the next radio frame through the second previous subframe 220 of the subframe in which each radio frame starts. That is, the terminal may receive information on the number of subframes (0) in the on state through the subframe 220 even if there is no subframe in the on-air frame.

The above state change information may include information about the number of subframes in the on state. That is, the state change information received in the 200 subframe may include information indicating that five subframes are on. Similarly, the state change information received in the 210 subframe may include information indicating that six subframes are on. Meanwhile, even when there is no subframe in the on state, information indicating that 0 subframes are in the on state may be included, such as state change information received in the 220 subframe.

FIG. 2 illustrates conveying information explicitly indicating a secondary cell on / off state through a PCell in a second subframe before an on state subframe. However, the subframe position including information explicitly indicating the cell on / off state may have a value different from that shown in FIG. 2. The value may be configured through the base station or may be set in advance in the terminal.

Referring to FIG. 3, the terminal may receive a signal for recognizing an on / off state for a specific radio frame (subframe) for the secondary cell through the secondary cell. For example, the signal capable of recognizing the on / off state may be a reference signal or a PDCCH or EPDCCH. The UE may know the small cell on / off state through this.

For example, the UE may check the on / off state of the small cell composed of the secondary cell by using the state change information received in the specific subframe 300 of the secondary cell. Similarly, the UE can check the on / off state of the small cell composed of the secondary cell by using the state change information received in the 310 subframe. The state change information may include the number of subframes to which the state change is applied or the subframe information at which the state change starts. Alternatively, as shown in FIGS. 1 and 2, the position of the subframe including the state change information may be predetermined.

FIG. 3 illustrates the transfer of information explicitly indicating a secondary cell on / off state through an SCell to an on state start subframe, but includes a subframe including information explicitly indicating a cell on / off state. The location may have a different value than that shown in FIG. 3. For example, it may be a subframe immediately before the on state start subframe. Alternatively, the value may be configured through the base station or may be set in advance in the terminal.

The L1 procedure for the small cell on / off transition described above is exemplarily illustrated. The L1 procedure described below may be the above-described L1 procedure or may be a different L1 procedure. For example, one of the explicitly on state or the off state may be implicitly recognized by the terminal without indicating through physical layer signaling, or a pattern for this may be preconfigured through the RRC configuration information. That is, the on state may be indicated through the PCell or the SCell, but the off state may not be set and indicated in advance. In another example, the on state may be indicated through the PCell, but the off state may be indicated through the corresponding SCell. In another example, a subframe pattern indicating an on state or an off state of the SCell through the SCell, but capable of receiving a physical layer signal indicating the on state or the off state of the SCell may be preset in the off state, It may be configured in advance through the RRC configuration information. For another example, the duration pattern for the on state and the duration pattern for the off state may be preset or preconfigured through the RRC configuration information.

Meanwhile, the terminal may transmit and receive data by configuring a small cell in an on state as a secondary cell. For example, the terminal may transmit and receive data by performing a handover to a small cell in an on state. As another example, the UE may add a small cell in an ON state as an RRC connection with the first base station cell as a PCell as a secondary cell, and activate the secondary cell to transmit and receive data. As another example, the terminal may transmit and receive data by adding a small cell, which is a secondary base station cell in an on state in an RRC connection state, through a first base station cell (or a cell associated with the first base station). When the small cell in the on state is not the primary secondary cell of the secondary base station, the secondary cell may be activated to transmit and receive data.

Hereinafter, specific operations of a terminal and a base station for carrying out the present invention will be described with reference to the drawings.

Referring to FIG. 4, the first cell 402 refers to a macro cell, and the second cell 403 refers to a small cell. The first cell and the second cell are cells associated with one base station. The terminal 401 receives measurement configuration information for measuring the cell discovery signal through the first cell 402 (S410). The measurement configuration information may include information necessary for the UE to receive the cell discovery signal and measure radio signal quality of the corresponding cell, such as a cell discovery signal transmission cycle, a transmission method, and offset information.

The terminal 401 receives a cell discovery signal from the second cell 403 (S420). As described above, the cell discovery signal is transmitted when the small cell is in the off state and may be transmitted when the second cell 403 is in the off state.

The terminal 401 may measure the radio signal quality of the cell transmitting the corresponding cell discovery signal based on the received measurement configuration information and the cell discovery signal (S430). Wireless signal quality measurement for the small cell can be made by the RRM measurement method as described above.

Meanwhile, the terminal 401 may transmit measurement information (eg, a measurement report) generated according to the radio quality measurement of the small cell to the base station through the first cell 402 (S440). The base station determines whether to further configure the small cell as a secondary cell in the terminal 401 in consideration of the received measurement information and the load of the macro cell.

The base station transmits the secondary cell additional configuration information to the terminal 401 through the first cell 402 (S450). The secondary cell additional configuration information includes information necessary for adding a small cell supporting the on / off function measured by the terminal 401 to the secondary cell, and may be transmitted through higher layer signaling. For example, the secondary cell additional configuration information may be included in the RRC connection reconfiguration message and transmitted.

Thereafter, the terminal 401 may perform communication by using the small cell added as the secondary cell.

Meanwhile, as described above, the small cell may support the on / off function. In addition, the secondary cell may perform data transmission and reception through an activation or deactivation operation. Therefore, when the small cell additionally configured as a secondary cell in the terminal supports the on / off function, it is necessary to define a secondary cell operation of the terminal according to the on / off indication information of the corresponding cell.

In a method of controlling a secondary cell operation, a terminal according to another embodiment of the present invention comprises the steps of: receiving measurement configuration information for measuring a cell discovery signal and measuring a cell based on the measurement configuration information and the cell discovery signal; The method may include transmitting the measurement information and additionally configuring a cell associated with the cell discovery signal as a secondary cell based on the higher layer signal.

Referring to FIG. 5, the terminal of the present invention may include receiving measurement configuration information for measuring a cell discovery signal (S510). The measurement configuration information necessary for measuring the cell discovery signal transmitted by the small cell in the off state may be received. For example, the measurement configuration information may include information necessary for detecting the small cell or measuring the radio signal quality of the small cell using the cell discovery signal. Alternatively, the measurement configuration information may include a type of cell discovery signal, a transmission period of the cell discovery signal, a transmission method and offset information.

The terminal may include transmitting wireless signal quality measurement information of the cell measured based on the measurement configuration information and the cell discovery signal (S520). For example, the terminal may measure the radio signal quality of the small cell transmitting the cell discovery signal by using the measurement configuration information and the received cell discovery signal. That is, RSRP, RSRQ, etc. of the cell discovery signal of the small cell can be measured. The terminal may transmit the measured channel state measurement information to the base station. The radio signal quality measurement information (for example, measurement report) is transmitted to the base station having an RRC connection with the terminal.

The terminal may further include configuring a cell associated with the cell discovery signal as a secondary cell based on the higher layer signal (S530). For example, the terminal may additionally configure a cell transmitting the cell discovery signal as a secondary cell based on the higher layer signal. The higher layer signal may be an RRC message including information related to the additional configuration when the base station additionally configures the small cell as a secondary cell in the terminal based on the channel state measurement information transmitted in step S520. For example, the higher layer signal may be an RRC connection reconfiguration message, and the additional configuration of the secondary cell may be indicated in a form in which an identifier of the corresponding small cell is added to the SCellToAddMod field of the RRC connection reconfiguration message. For another example, the additional configuration of the secondary cell may be indicated in a form including configuration information for additional configuration of the unlicensed band cell in the RRC connection reconfiguration message.

Meanwhile, as described below in detail with respect to each embodiment, the added secondary cell may be a cell associated with the master base station or a cell associated with the secondary base station. In addition, the secondary cell may be added in the off state or may be added in the on state.

Referring to FIG. 6, a terminal of the present invention receives a physical layer signal including information indicating an on state or an off state of a secondary cell, and activates or deactivates the terminal for the secondary cell based on the physical layer signal. The method may further include controlling an operation.

For example, as shown in FIG. 5, the terminal may include receiving measurement configuration information for measuring a cell discovery signal (S610). That is, the measurement configuration information necessary for measuring the cell discovery signal transmitted by the small cell in the off state can be received. In addition, the terminal may include transmitting the measurement information of the cell measured based on the measurement configuration information and the cell discovery signal (S620). For example, the terminal may measure the radio signal quality of the small cell transmitting the cell discovery signal by using the measurement configuration information and the received cell discovery signal. The terminal may further include configuring a cell associated with the cell discovery signal as a secondary cell based on the higher layer signal (S630). For example, the terminal may additionally configure a cell transmitting the cell discovery signal as a secondary cell based on the higher layer signal.

Meanwhile, the terminal may further include receiving a physical layer signal including information indicating an on state or an off state of the secondary cell (S640). For example, when the small cell is additionally configured as the secondary cell in the on state or the off state as in the following embodiments, the terminal may be configured to consider the secondary cell as an inactive state. Thereafter, information indicating the on state of the secondary cell can be received from the base station through a physical layer signal (for example, L1 signaling). (Or, after receiving the MAC signal indicating activation, information indicating the on state of the secondary cell may be received through the physical layer signal.) For example, the unlicensed band small cell is in an on state or When additionally configured as a secondary cell in the off state, the terminal may configure the secondary cell as an unlicensed band cell. Thereafter, information indicating an on state or an off state of the corresponding secondary cell may be received from the base station through a physical layer signal (eg, L1 signaling).

Thereafter, the terminal may include controlling the secondary cell activation operation or the secondary cell deactivation operation of the terminal based on the physical layer signal (S650). For example, when the physical layer signal includes information indicating the on state of the secondary cell, the terminal may control to perform a part of the secondary cell activation or the secondary cell activation of the terminal for the secondary cell. The secondary cell activation operation includes transmitting an uplink reference signal (SRS) on the secondary cell, transmitting channel state information (CSI) reporting for the secondary cell, monitoring the control channel on the secondary cell, and the secondary. One or more of the control channel monitoring operations for the cell. That is, the terminal may control to perform all of the above-described activation operations, or may control to perform some of the above-described activation operations.

As another example, when the physical layer signal includes information indicating the off state of the secondary cell,

The terminal may be controlled to perform a deactivation operation of the terminal or a part of the secondary deactivation operation with respect to the secondary cell. Secondary cell deactivation operation does not transmit an uplink reference signal (SRS) on the secondary cell, does not transmit an uplink shared channel on the secondary cell, does not transmit a random access channel on the secondary cell, secondary Means an operation of controlling one or more of not performing channel state information reporting for a cell, not performing control channel monitoring on the secondary cell, and not performing control channel monitoring on the secondary cell. That is, the terminal may control to perform all of the aforementioned cell deactivation operations, or may control some of them.

The present invention provides a method for controlling a secondary cell operation of a mobile station by a base station, comprising: measuring configuration information for measuring a cell discovery signal and wireless signal quality measurement information of a cell associated with a cell discovery signal measured based on the cell discovery signal And transmitting a higher layer signal including information for controlling the terminal to additionally configure the cell associated with the cell discovery signal as the secondary cell.

Referring to FIG. 7, the base station includes receiving measurement configuration information for measuring a cell discovery signal and measurement information of a cell associated with the measured cell discovery signal based on the cell discovery signal (S710). For example, the base station may receive radio signal quality measurement information of the small cell measured by the terminal based on the cell discovery signal. If necessary, the base station may transmit measurement configuration information including information necessary for the terminal to measure the cell discovery signal. The cell discovery signal is transmitted by the small cell in the off state, and the terminal may measure the small signal or the radio signal quality of the small cell by using the cell discovery signal. Thereafter, the terminal may transmit channel state measurement information to the base station. Here, the small cell may be a cell associated with the base station, or may be a cell associated with another base station (eg, a secondary base station) connected to the base station through an X2 interface.

The base station may include transmitting a higher layer signal including information for controlling the terminal to additionally configure a cell associated with the cell discovery signal as a secondary cell (S720). For example, the base station may control to configure the small cell as a secondary cell of the terminal in consideration of the channel state measurement information received from the terminal and the number or traffic load of the terminal located in the small cell. To this end, the base station may transmit information for controlling to configure the secondary cell to the terminal through the higher layer signal. For example, the higher layer signal may be an RRC message and may be transmitted by including identifier information of the corresponding small cell in the SCellToAddMod field in the RRC connection reconfiguration message. As another example, when the unlicensed band cell is added as the secondary cell, the RRC connection reconfiguration message may be transmitted including configuration information for additionally configuring the unlicensed band cell.

On the other hand, the base station may determine and control the on / off state change of the small cell. In addition, the secondary cell added to the terminal may be added in the off state or on state, it may be added in an inactive or activated state. Alternatively, when the unlicensed band cell is added as the secondary cell, the secondary cell added to the terminal may be added in the off state or the on state and may be added as the unlicensed band cell.

The base station of the present invention may further include transmitting a physical layer signal including information indicating an on state or an off state of the secondary cell.

Referring to FIG. 8, the base station includes receiving measurement configuration information for measuring a cell discovery signal and measurement information of a cell associated with the measured cell discovery signal based on the cell discovery signal (S810). For example, the base station may receive radio signal quality measurement information of the small cell measured by the terminal based on the cell discovery signal.

The base station may include transmitting a higher layer signal including information for controlling the terminal to further configure a cell associated with the cell discovery signal as a secondary cell (S820). For example, the base station may control to configure the small cell as a secondary cell of the terminal in consideration of the measurement information received from the terminal and the number or traffic load of the terminal located in the small cell.

In addition, the base station may include transmitting a physical layer signal including information indicating an on state or an off state of the secondary cell (S830). The base station may transmit a physical layer signal including information indicating whether the secondary cell additionally configured to the on state or off state. As described above, the secondary cell may change the state to the on state or the off state, and the terminal may configure the corresponding secondary cell into an activated or deactivated state. Alternatively, when the unlicensed band cell is added as the secondary cell, the secondary cell may change the state to an on state or an off state, and the terminal may configure the secondary cell as an unlicensed band cell state.

Accordingly, the base station may transmit information indicating on / off of the secondary cell to the terminal. In this case, the indication information indicating the on state or the off state transmitted from the base station to the terminal may be transmitted through a physical layer signal. The physical layer signal is a signal distinct from the conventional MAC control element, and may be, for example, a physical layer control channel.

For example, the terminal that receives the physical layer signal including information indicating the on state of the secondary cell is performed by the secondary cell activation operation or a part of the secondary cell activation operation of the terminal for the secondary cell additionally configured according to the corresponding physical layer signal. Can be controlled. For example, at least one of an uplink reference signal transmission operation on the secondary cell, a channel state information reporting transmission operation for the secondary cell, a control channel monitoring operation on the secondary cell, and a control channel monitoring operation for the secondary cell may be performed. have.

.

As another example, the terminal receiving the physical layer signal including information for controlling the secondary cell to be deactivated may control the deactivation operation of the terminal or the part of the secondary deactivation operation to be performed. For example, do not transmit an uplink reference signal on the secondary cell, do not transmit an uplink shared channel on the secondary cell, do not transmit a random access channel on the secondary cell, do not report channel state information for the secondary cell. One or more of not performing control channel monitoring on the secondary cell and not performing control channel monitoring on the secondary cell may be controlled.

Hereinafter, a method for additionally configuring the above-described small cell as a secondary cell and a specific method for instructing activation of the additionally configured secondary cell will be described with reference to each embodiment.

오프 상태 스몰 셀의 온 상태 전환Toggle the off state of the off state small cell

The terminal or the base station may transmit and receive data by configuring the small cell in the off state as a secondary cell according to the following embodiments.

Embodiment 1: Performing a cell add / config procedure after switching from off state to on state.

After the small cell is turned on, the terminal may additionally configure the small cell as a secondary cell to perform communication.

For example, when the small cell is in an off state, the small cell may transmit a cell discovery signal. The terminal may detect the small cell in the off state based on the cell discovery signal. Alternatively, the terminal may measure the radio signal quality of the off state small cell based on the cell discovery signal.

The terminal measures the small cell radio signal quality and reports radio signal quality measurement information to the base station. In measuring the radio signal quality of the small cell, the terminal may measure the radio signal quality using measurement configuration information for measuring the cell discovery signal and the cell discovery signal.

The base station performs on-state transitions of the small cell based on traffic load, serving cell load, user arrival / departure, number of users, packet arrival / completion, radio quality or channel state measurement information, and maximum channel occupancy period of the unlicensed band cell. You can decide.

If the base station determines to switch the state of the small cell to the on state, the base station switches the small cell to the on state when the small cell which determines the on state switching is a cell provided by the same base station. On the other hand, when the small cell which determines the on state transition is a cell provided by another base station connected through the X2 interface, the base station transfers the indication information for switching the small cell on to the base station to switch the small cell on. can do.

Thereafter, the terminal and the base station may transmit and receive data by configuring a small cell in an on state as a secondary cell. For example, the terminal may transmit and receive data by performing a handover to a small cell in an on state. As another example, the terminal may add a small cell in an on state of RRC connection using the master base station cell as the PCell as a secondary cell, and activate the secondary cell to transmit and receive data. As another example, the terminal adds a small cell in an on state, which is a secondary base station cell (or a cell associated with a secondary base station) in an on state in which an RRC connection is established through a master base station cell (or a cell associated with the master base station) to the secondary base station cell. To send and receive data. When the small cell in the on state is not the primary secondary cell of the secondary base station, the secondary cell may be activated to transmit and receive data.

To reduce the on-state transition time, if the small cell where the base station determines the on state transition is a cell provided by another base station connected through an X2 interface, the base station turns on the small cell to another base station (eg, the second base station). The indication information for switching to the state may be transmitted in a handover request message or a secondary base station addition request message.

As described above, in the first embodiment, the base station may be configured to be configured in the terminal by turning on the small cell for additional configuration as a secondary cell in the terminal.

Second Embodiment: Allow Small Cell Addition / Configuration in the Off State.

The UE may perform communication by additionally configuring the small cell as the secondary cell when the small cell is in the off state.

The terminal measures the small cell radio signal quality and reports radio signal quality measurement information to the base station. In measuring the radio signal quality of the small cell, the terminal may measure the cell discovery signal using measurement configuration information and the cell discovery signal for measuring the cell discovery signal.

The base station may configure the small cell in the off state as a secondary cell based on the radio quality measurement information. As described above, the configuration of the secondary cell includes both cases of configuring the corresponding small cell as a serving cell, an additional serving cell, or a secondary base station serving cell.

For example, a base station may transmit a higher layer signal for adding a small cell in an off state to a secondary cell to a terminal for a terminal having an RRC connection using the master base station cell as a PCell. For example, the higher layer signal may be an RRC connection reconfiguration message including cell add configuration information (SCellToAddMod). The cell additional configuration information (or RRC connection reconfiguration message or measurement configuration information or signaling transmitted by the base station to the terminal) includes information indicating that the small cell additionally configured as the secondary cell and / or cell discovery signal measurement of the off state small cell Information may be included. Alternatively, the cell additional configuration information may not include information indicating that the small cell additionally configured as the secondary cell is off. For another example, when adding an unlicensed band cell as a secondary cell, the RRC connection reconfiguration message may be indicated by including configuration information for additional configuration of the unlicensed band cell.

The terminal may perform radio signal quality measurement on the small cell in the off state configured as the secondary cell based on the cell discovery signal. The cell discovery signal may be transmitted to the small cell in the off state composed of the secondary cell at a frequency distinguished from the small cell in the off state not composed of the secondary cell. For example, the cell discovery signal of the small cell in the off state configured as the secondary cell may be transmitted more frequently or rarely than the cell discovery signal of the small cell in the off state not configured as the secondary cell. Alternatively, the transmission frequency of the cell discovery signal may be set to be the same.

The terminal may be configured to add the small cell included in the cell additional configuration information as the secondary cell and to consider the secondary cell as an inactive state in the lower layer.

The terminal may perform off state small cell detection and / or off state small cell radio signal quality measurement based on the cell discovery signal and report radio signal quality measurement information to the base station. Alternatively, the terminal may not perform off state small cell detection and / or off state small cell radio signal quality measurement based on the cell discovery signal.

The base station performs on-state transitions of the small cell based on traffic load, serving cell load, user arrival / departure, number of users, packet arrival / completion, radio signal quality or channel state measurement information, and maximum channel occupancy period of the unlicensed band cell. You can decide. According to the result of the above-described on-state switching decision, the base station may switch the small cell on.

Thereafter, the base station may transmit an activation / deactivation MAC control element for activating the secondary cell through the PCell.

The base station may transmit and receive data through the activated small cell.

As another example, the ON state transition of the small cell and the activation / deactivation MAC control element transmission of the secondary cell may be performed at the same time.

As another example, the activation / deactivation MAC control element transmission of the secondary cell may occur before the on state transition of the small cell. The UE performs an action related to activation / deactivation within a minimum requirement (for delay) specified in 3GPP TS36.133 after the subframe receiving the activation / deactivation MAC control element of the secondary cell from the base station. Considering the delay time until the UE performs the operation related to the actual activation / deactivation when the UE receives the activation / deactivation MAC control element of the secondary cell, the MAC control element transmission occurs before the on / off indication of the small cell. Can be.

In the above, the case where the small cell is added as the secondary cell has been described as an example. However, in a similar manner small cells may be added to the secondary base station cell. Hereinafter, a case in which the small cell is added to the secondary base station cell will be described in detail.

For a terminal that has established an RRC connection through the master base station cell, the master base station may transmit a higher layer signal for adding the small cell to the secondary base station cell through the secondary base station addition procedure.

The secondary base station cell in the off state may not be configured as a secondary base station primary secondary cell (SeNB PSCell) that is always in an activated state. Alternatively, when there is a cell in an on state among the secondary base station cells, one of the cells in the on state among the secondary base station cells may be configured as a secondary base station primary secondary cell for the terminal. Alternatively, the secondary base station cell in the off state may include information for requesting on-state switching in the secondary base station addition request message, and configure the secondary base station cell in the on state as a secondary base station primary secondary cell which is always in an activated state.

Information for additionally configuring the small cell in the off state as the secondary base station cell (or RRC reconfiguration message or measurement configuration information or signaling transmitted by the base station to the terminal) includes information indicating that the small cell additionally configured as the secondary base station cell is in the off state and / or Information for measuring a cell discovery signal of an off state small cell may be included. Alternatively, the information for additionally configuring the small cell in the off state as the secondary base station secondary cell may not include information indicating that the small cell additionally configured as the secondary base station cell is in the off state.

The terminal may perform measurement based on the cell discovery signal for the small cell in the off state composed of the secondary base station cell. For the small cell in the off state configured as the secondary base station cell, the cell discovery signal may be transmitted at a frequency distinguished from the small cell in the off state not configured as the secondary base station cell. For example, the cell discovery signal of the small cell in the off state configured as the secondary base station cell may be transmitted more frequently or rarely than the cell discovery signal of the small cell in the off state not configured as the secondary base station cell. Alternatively, the transmission frequency of the cell discovery signal may be set to be the same.

The terminal may add the small cell of the secondary base station included in the higher layer signal (eg, an RRC message) as the secondary base station cell, and configure the corresponding secondary cell in an inactive state in the lower layer.

Based on the cell discovery signal, off-state small cell detection and / or off-state small cell measurement may be performed and radio signal quality measurement information may be reported to the base station. Or, the terminal may not perform off state small cell detection and / or off state small cell measurement based on the cell discovery signal.

The secondary base station determines the on-state transition of the small cell based on traffic load, serving cell load, user arrival / leave, number of users, packet arrival / completion, channel state measurement information, and maximum channel occupancy period of the unlicensed band cell.

The secondary base station turns the small cell on.

The secondary base station may transmit an activation / deactivation MAC control element for activating the small cell in the off state through the secondary base station primary secondary cell.

The secondary base station may transmit and receive data through the activated small cell.

Third Embodiment: Turning Off State Small Cell On Through the L1 Procedure.

The base station of the present invention may further configure the small cell in the off state as a secondary cell, and switch to the on state through the L1 procedure. Alternatively, the base station may additionally configure the small cell in the off state as the secondary cell, and allow the terminal to perform the secondary cell activation operation through the L1 procedure.

In the small cell off state, the small cell may transmit a cell discovery signal.

The terminal may perform off state small cell detection and / or off state small cell radio signal quality measurement based on the cell discovery signal.

The terminal reports radio signal quality measurement information to the base station.

The base station may configure the small cell in the off state as a secondary cell based on the radio signal quality measurement information. Here, the secondary cell is meant to include all of the above-described serving cell or additional serving cell or secondary base station cell.

For example, for a terminal having an RRC connection using the master base station cell as a PCell, the base station includes a higher layer signal (eg, RRC connection reconfiguration) including cell additional configuration information (SCellToAddMod) for adding a small cell in an off state to a secondary cell. Message) to the terminal. The terminal adds the small cell included in the cell additional configuration information as the secondary cell and configures the secondary cell to be considered in an inactive state in the lower layer.

As another example, in a state where the small cell is previously turned on, the UE may configure the small cell as a secondary cell and consider the corresponding secondary cell to be in an inactive state.

As another example, when the unlicensed band cell is added as the secondary cell, the base station may transmit configuration information for additionally configuring the unlicensed band cell in the RRC connection reconfiguration message to the terminal. When the terminal adds the unlicensed band small cell to the secondary cell, the unlicensed band cell may be in an on state (period in which the unlicensed band cell channel can occupy or a period in which the unlicensed band cell is available), or the terminal adds the unlicensed band small cell to the secondary cell When added to a cell, the unlicensed band cell may be in an off state (period when the channel is not occupied by the unlicensed band cell or during which the unlicensed band cell is unavailable). The terminal may be configured to consider the unlicensed band secondary cell in an inactive state, or the terminal may configure the unlicensed band secondary cell to a specific state for the unlicensed band. In the specific state for the unlicensed band described above, a terminal according to the present invention may perform a portion of a normal secondary cell operation (for example, PDCCH monitoring for a corresponding secondary cell, or another example, for an SRS transmission operation or a secondary cell). One or more of a CQI / PMI / RI / PTI reporting operation, a PDCCH monitoring operation on a secondary cell, and a PDCCH monitoring operation on a secondary cell).

The base station determines the off-state switching of the small cell based on traffic load, serving cell load, user arrival / departure, number of users, packet arrival / completion, radio signal quality measurement information, and maximum channel occupancy period of the unlicensed band cell. The UE may perform off-state small cell detection and / or radio signal quality measurement of the off-state small cell based on the cell discovery signal, and report radio signal quality measurement information to the base station. Or, the terminal may not perform off state small cell detection and / or off state small cell measurement based on the cell discovery signal.

Or, the base station determines the on state transition of the small cell based on traffic load, serving cell load, user arrival / leaving, number of users, packet arrival / completion, measurement report, maximum channel occupancy period of the unlicensed band cell, and the like. The base station turns the small cell on.

In this case, information indicating the on state of the corresponding secondary cell may be transmitted through a physical layer signal (L1 procedure).

For example, the base station may activate a secondary cell of the terminal by performing a new L1 procedure for reducing the small cell on / off transition time with the terminal through the PCell. That is, when the terminal receives a physical layer signal indicating the on state of the secondary cell with respect to the secondary cell, the terminal may perform a normal secondary cell operation or a part of the normal secondary cell operation for the secondary cell.

As another example, the base station may perform a new L1 procedure to reduce the small cell on / off transition time with the terminal through the PCell to switch the small cell in the off state to the on state and activate the secondary cell operation of the terminal. That is, when the terminal receives a physical layer signal indicating the on state of the secondary cell with respect to the secondary cell, the terminal may perform a normal secondary cell operation or a part of the normal secondary cell operation for the secondary cell.

As another example, the base station performs a new L1 procedure for reducing the small cell on / off transition time with the terminal through the PCell to switch the small cell in the off state to the on state, and the terminal performs one or more of the normal secondary cell operations. It can be controlled to perform.

As another example, the base station may perform a new L1 procedure for reducing the small cell on / off transition time with the terminal through the PCell to allow the terminal to perform one or more of the normal secondary cell operations.

As another example, the base station performs a new L1 procedure to reduce the terminal and the small cell on / off transition time through the PCell to control the terminal in the inactive state to perform at least one operation of the base station in the on state and the normal secondary cell operation can do.

As another example, the base station performs a new L1 procedure that reduces the UE and small cell on / off transition time through the SCell to switch the small cell in the off state to the on state, and the terminal operates at least one of the normal secondary cell operations. It can be controlled to perform.

As another example, the base station performs a new L1 procedure to reduce the UE and the small cell on / off transition time through the serving cell to switch the small cell in the off state to the on state, and the terminal performs one or more of the normal secondary cell operations. Control to perform an operation.

The normal secondary cell operation is the SRS transmissions on the SCell, the CQI / PMI / RI / PTI reporting operation for the secondary cell (CQI / PMI / RI / PTI reporting for the SCell). May include one or more of PDCCH monitoring on the SCell and PDCCH monitoring for the SCell on the secondary cell.

Thereafter, the base station can transmit and receive data with the terminal through the small cell.

The on state transition and the L1 procedure of the small cell described above may be simultaneously performed. Alternatively, the L1 procedure may occur earlier than the on state transition of the small cell. For example, after the UE receives the physical layer signal (L1 procedure) and performs the L1 procedure in consideration of the delay time until the on-state operation or the activation related operation is performed in the corresponding secondary cell. The on state transition can be performed (for example after a certain subframe, for example after a predefined subframe).

Hereinafter, when the small cell described above is a cell associated with the secondary base station, the operation of the terminal and the base station will be described once again. That is, the case where the small cell described above is added to the secondary base station cell will be described.

In this case, the master base station may transmit an RRC connection reconfiguration message for adding the small cell in the off state to the secondary base station cell through the secondary base station addition procedure for the terminal that has made the RRC connection through the master base station cell.

For example, the secondary base station cell in the off state may be controlled not to be configured as the secondary base station primary secondary cell which is always in an activated state.

As another example, when there is a cell in an on state among the secondary base station cells, one of the cells in the on state among the secondary base station cells may be configured as a secondary base station primary secondary cell.

As another example, the secondary base station cell in the off state may include information for requesting on-state transition in the secondary base station addition request message, such that the secondary base station cell in the on state may be configured as a secondary base station primary secondary cell which is always in an activated state. have.

As another example, the secondary base station cell in the off state may be configured as a secondary base station primary secondary cell, and in this case, the secondary base station may perform the aforementioned L1 procedure through the secondary base station primary secondary cell. That is, the secondary base station primary secondary cell is activated or switched on or switched on through the L1 procedure so that the terminal can perform one or more operations of the normal secondary cell operation to transmit and receive data. The UE may monitor the PDCCH during the cell discovery signal measurement cycle so that the secondary base station can perform the above-described L1 procedure through the secondary base station primary secondary cell. Alternatively, the terminal may be configured to monitor the PDCCH at a specific time.

As another example, the UE may add a small cell of the secondary base station included in the RRC message as the secondary base station secondary cell and configure the corresponding secondary cell in a lower layer in an inactive state.

Thereafter, the terminal may perform off state small cell detection and / or off state small cell channel state measurement based on the cell discovery signal, and report the channel state measurement information to the base station. Or, the terminal may not perform off state small cell detection and / or off state small cell channel state measurement based on the cell discovery signal.

The secondary base station may determine the on-state transition of the small cell based on traffic load, serving cell load, user arrival / leaving, number of users, packet arrival / completion, measurement report, maximum channel occupancy period of the unlicensed band cell, and the like.

The secondary base station turns the small cell on.

For example, the secondary base station may activate a small cell operation of the terminal by performing a new L1 procedure for reducing a small cell on / off transition time with the terminal through the secondary base station primary secondary cell. That is, when the terminal receives a physical layer signal indicating the on state of the secondary cell with respect to the secondary cell, the terminal may perform a normal secondary cell operation or a part of the normal secondary cell operation for the secondary cell.

As another example, the secondary base station performs a new L1 procedure to reduce the UE and small cell on / off transition time through the secondary base station primary secondary cell to switch the small cell in the off state to the on state, and the secondary cell operation of the terminal is performed. Can be activated. That is, when the terminal receives a physical layer signal indicating the on state of the secondary cell with respect to the secondary cell, the terminal may perform a normal secondary cell operation or a part of the normal secondary cell operation for the secondary cell.

As another example, the secondary base station performs a new L1 procedure that reduces the UE and the small cell on-off transition time through the secondary base station primary secondary cell to switch the small cell in the off state to the on state, and the terminal is a secondary cell It may be controlled to perform one or more of the operations.

As another example, the secondary base station may control to perform at least one of normal secondary cell operations by performing a new L1 procedure that reduces the UE and small cell on / off transition time through the secondary base station primary secondary cell.

The normal secondary cell operation above includes SRS transmissions on the SCell, CQI / PMI / RI / PTI reporting operation for the secondary cell (CQI / PMI / RI / PTI reporting for the SCell), The secondary cell may include at least one of a PDCCH monitoring operation on the SCell and a PDCCH monitoring operation for the secondary cell.

The secondary base station may transmit and receive data through the small cell.

Fourth Embodiment: Turning an On-State Cell from an Activated State to an Off State Through an L1 Procedure

When the small cell is in an on state, the terminal may transmit and receive data through the small cell. As an example, the UE may transmit and receive data by performing a handover to a small cell in an on state. As another example, the terminal may add a small cell in an on state of RRC connection using the master base station cell as the PCell as a secondary cell, and activate the secondary cell to transmit and receive data. As another example, the terminal adds a small cell in an on state, which is a secondary base station cell (or a cell associated with a secondary base station) in an on state in which an RRC connection is established through a master base station cell (or a cell associated with the master base station) to the secondary base station cell. To send and receive data. When the small cell in the on state is not the primary secondary cell of the secondary base station, the secondary cell may be activated to transmit and receive data. As another example, when the small cell in the on state or the off state is an unlicensed band cell, when the unlicensed band cell is configured, the terminal may transmit and receive data by performing a secondary cell activation operation in the on state.

The base station may determine the off-state transition of the small cell based on traffic load, serving cell load, user arrival / leaving, number of users, packet arrival / completion, measurement report, maximum channel occupancy period of the unlicensed band cell, and the like.

As an example, the base station maintains the small cell in the on state when there is a terminal having an RRC connection using the small cell in the on state as the PCell. This is because, when the UE having the RRC connection with the small cell as the PCell exists, the UE may generate a radio link failure (RFL) when the small cell is turned off. In this case, the terminal may be moved to another cell through handover and the off state of the cell may be determined.

As another example, the base station may determine to switch off the small cell when the number of terminals configured by adding the small cell in the on state as the secondary cell is within a certain number. Alternatively, the base station may determine the switching off state of the small cell when the amount of forwarded packets of the UEs configured by adding the small cell in the on state as the secondary cell is less than a predetermined level. Alternatively, the base station may add the small cell in the on state as a secondary cell to determine the off state transition of the small cell when the packet to be delivered to the configured terminal does not arrive.

As another example, if there is a legacy UE before Release 12 configured by adding a small cell in an on state as a secondary cell, if the corresponding small cell is in an inactive state, the base station preferentially transmits the legacy UE before Release 12. In response to the release of the corresponding small cell configured as a secondary cell and other factors (for example, when the number of Release 12 terminals is within a certain number or when the amount of forwarded packets of the terminals is below a certain level), the off state transition may be determined. . For example, when the number of terminals in the active state is within the reference number or when the amount of packets transmitted by the terminals is less than a predetermined level or when the packet to be delivered to the terminal is not reached, the secondary cell in the activated state may be determined to be switched off. . Legacy UEs prior to Release 12 perform only CRS-based measurements and cannot perform cell discovery signal-based measurements. When the small cell added as the secondary cell is switched to the off state, a legacy terminal before Rel-12 cannot perform CRS-based measurement and may not perform DRS-based measurement through the small cell in the off state. have. Accordingly, in determining the small cell on / off, the base station may consider the number of legacy terminals before Rel-12 or the configuration state of legacy terminals before Release 12. In addition, the base station may allow the secondary cell release to be performed first before switching the secondary cell to the off state.

As another example, the secondary base station may determine to switch off the small cell when the number of terminals configured by adding the small cell in the on state as the secondary base station secondary cell is within a certain number or when the amount of forwarded packets of the terminals is less than or equal to a certain level. have.

As another example, if there is a legacy UE before Release 12 configured by adding a small cell in an on state as a secondary base station secondary cell, if the small cell is in an inactive state, the legacy base station prior to Rel-12 is preferentially. When the small cell consisting of the secondary base station secondary cell is released and other factors (for example, the number of Rel-12 terminals is within a certain number, or the amount of forwarding packets of the terminals is below a certain level, or the packet to be delivered to the terminal has not arrived Case), it is possible to determine the off state transition of the secondary cell. Legacy UEs before Rel-12 perform only CRS-based measurements and cannot perform cell discovery signal-based measurements. Therefore, when the small cell added as the secondary base station secondary cell is turned off, the legacy UE before Rel-12 cannot perform CRS based measurement through the small cell in the off state, and can also perform cell discovery signal based measurement. Missing problems can occur. Accordingly, the base station may consider the number of legacy terminals before Rel-12 or the configuration of legacy terminals before Rel-12 in determining the small cell on / off. In addition, the base station may allow the secondary cell release to be performed first before switching the secondary cell to the off state.

As another example, when using an unlicensed band cell, the base station may determine to switch off the small cell when the period in which the unlicensed band cell channel occupies or the period in which the unlicensed band cell is available expires.

Based on the off state determination method described above, the base station switches the small cell to the off state.

For example, when the corresponding small cell is a secondary cell (or a secondary cell when dual connectivity is applied or when it is a secondary cell instead of a primary secondary cell when dual connectivity is applied), the UE operates a normal secondary cell when the cell is activated. It can be controlled to perform. Here, the normal secondary cell operation is the SRS transmissions on the SCell, the CQI / PMI / RI / PTI reporting operation for the secondary cell (CQI / PMI / RI / PTI reporting for the SCell). The second cell may include one or more of PDCCH monitoring on the SCell and PDCCH monitoring for the SCell.

However, when the small cell is switched off in a situation in which the corresponding secondary cell is configured to be activated in the terminal, it may be inefficient for the terminal to perform all or part of the normal secondary cell operation in the activated state. In addition, when the small cell is in the off state, the secondary cell configured in the terminal may perform an error in the conventional secondary cell operation in the activated state. That is, when the small cell is switched to the off state and transmits only the cell discovery signal, the terminal cannot perform the operation of the conventional conventional secondary cell, and an error may occur when the normal secondary cell operation described above is performed. Therefore, when the secondary cell is in the activated state, when the small cell is switched to the off state, the terminal and the base station need to perform the following operation.

For example, the base station may deactivate the operation of the small cell of the terminal by performing a new L1 procedure for reducing the small cell on / off transition time with the terminal through the PCell (or PSCell cell or SCell). That is, when the UE receives a physical layer signal indicating the OFF state of the secondary cell with respect to the secondary cell, the UE may perform a part of an inactive secondary cell operation or an inactive secondary cell operation with respect to the secondary cell. Can be.

As another example, the base station performs a new L1 procedure for reducing the small cell on / off transition time with the terminal through the PCell (or PSCell cell or SCell) to switch the small cell in the on state to the off state, the secondary cell operation of the terminal Can be disabled. That is, when the UE receives a physical layer signal indicating the OFF state of the secondary cell with respect to the secondary cell, the UE may perform a part of an inactive secondary cell operation or an inactive secondary cell operation with respect to the secondary cell. Can be.

As another example, the base station performs a new L1 procedure to reduce the small cell on / off transition time with the terminal through the PCell (or PSCell cell or SCell) to instruct the on-state small cell to switch off, The corresponding operation can be made. For example, the terminal may confirm that the secondary cell configured in the activated state is changed from the on state to the off state through the aforementioned L1 procedure. In this case, the terminal recognizes that the secondary cell configured in the terminal is switched to the off state through the L1 procedure indicating the off state of the secondary cell, the terminal may perform one or more operations during the operation when the secondary cell is deactivated. . For example, the terminal does not perform transmission through the secondary cell (not transmit SRS on the SCell, not transmit on UL-SCH on the SCell, not transmit on RACH on the SCell not performed), the secondary cell Without performing a CQI / PMI / RI / PTI report (not report CQI / PMI / RI / PTI for the SCell), the second cell may not monitor (not monitor the PDCCH on the SCell). However, the UE may perform PDCCH monitoring for the secondary cell through the PCell. As another example, the UE does not perform transmission through the secondary cell (not transmit SRS on the SCell, not transmit on UL-SCH on the SCell, not transmit on RACH on the SCell), and on the secondary cell Only PDCCH monitoring for the secondary cell may be performed through monitoring and / or PCell. As another example, the random access procedure through the secondary cell may not be performed. Alternatively, a random access procedure may be performed through the primary cell. Alternatively, the random access procedure through the secondary cell may be suspended. As another example, the scheduling request (SR) procedure through the secondary cell may not be performed. Alternatively, the scheduling request procedure may be performed through the primary cell. Alternatively, the scheduling request (SR) procedure through the secondary cell may be suspended.

The activation operation of the secondary cell of the terminal by the MAC Control Element of the conventional 3GPP TS 36.321 follows the timing related standard of 3GPP TS 36.213. The TS 36.213 timing specifications are as follows.

When the UE receives an activation command for the secondary cell in subframe n, the corresponding actions are more than the minimum requirements defined in 3GPP TS 36.133 except for the following, which should be applied to subframe n + 8. It should be applied not later and not faster than subframe n + 8.

Actions related to CSI reporting

The action associated with the sCellDeactivationTimer associated with the secondary cell

The minimum requirements defined in 3GPP TS36.133 are as follows.

For the SCell activation delay requirement, if the UE sends a valid measurement report for a period such as max (5 measCycleSCell, 5 DRX cycles) before the receipt of the SCell activation command and it is later than subframe n + 24 if the SCell remains detectable Otherwise, the terminal should be able to apply the operation not later than subframe n + 34.

As such, there is a delay time until the terminal receives the activation MAC control element and performs operations for actual activation. Therefore, when the terminal instructs the cell on / off through the above-described physical layer signal, the terminal may perform the related operation according to the state in which the cell can perform the normal secondary cell operation in the activated state. For example, via the PCell (or through the SCell) to indicate the on or off state of the secondary cell, or, for example, via the PCell (or via the SCell) to indicate the duration of the secondary cell's on state and on state, or The duration pattern for the on state or the on-off state or the duration pattern for the off state or the duration pattern for the on-off state may be preset or preconfigured through the RRC configuration information. When recognizing a state, the UE recognizes the on / off state indication of the cell or the on / off state of the cell in a state in which the cell can perform a normal secondary cell operation or a part of the normal secondary cell operation in an activated state. In this case, some operations of the associated secondary cell terminal operation may be performed or changed.

For example, the terminal may configure the small cell in the off state as a secondary cell and configure the corresponding secondary cell to be considered in an inactive state.

The base station activates the corresponding secondary cell through the MAC control element.

The base station turns the corresponding secondary cell on through the above-described physical layer signaling (L1 procedure).

The activation of the corresponding secondary cell through the MAC control element and the on state transition of the secondary cell may be initiated either on-state transition first or at the same time, as shown in the present invention. If the terminal operation is defined, the secondary cell activation may be started first.

When the base station determines to switch off the secondary cell, the base station switches the secondary cell to the off state through the above-described physical layer signaling (L1 procedure). Or, the base station and the terminal recognizes the off state transition of the secondary cell.

The terminal performs a part of the secondary cell deactivation operation or the secondary cell deactivation operation.

Then, when the base station determines the on state transition of the secondary cell, the base station switches the secondary cell to the on state through the above-described physical layer signaling (L1 procedure). Or, the base station and the terminal recognizes the on state transition of the secondary cell.

The terminal performs a part of the secondary cell activation or the secondary activation.

As another example, when the unlicensed band cell is added as the secondary cell, the base station may transmit configuration information for additionally configuring the unlicensed band cell in the RRC connection reconfiguration message to the terminal. When the terminal adds the unlicensed band small cell to the secondary cell, the unlicensed band cell may be in an on state (period in which the unlicensed band cell channel can occupy or a period in which the unlicensed band cell is available), or the terminal adds the unlicensed band small cell to the secondary cell When added to a cell, the unlicensed band cell may be in an off state (period when the channel is not occupied by the unlicensed band cell or during which the unlicensed band cell is unavailable).

The terminal may be configured to consider the unlicensed band secondary cell in an inactive state. Alternatively, the terminal may configure the corresponding unlicensed band secondary cell in a specific state for the unlicensed band. (Or, the terminal may configure the corresponding unlicensed band secondary cell.) Alternatively, the terminal may configure the corresponding unlicensed band secondary cell in an off state.

As described above, the specific state for the unlicensed band may indicate a state in which the terminal according to the present invention may perform normal secondary cell operation or part of normal secondary cell operation.

As an example (when configuring an unlicensed band cell in the on state), when the base station determines to switch off the secondary cell, the base station switches the secondary cell to the off state through the aforementioned physical layer signaling (L1 procedure). do. Or, the base station and the terminal recognizes the off state transition of the secondary cell.

The terminal performs a part of the secondary cell activation operation or the secondary cell deactivation operation.

As another example (if configuring an unlicensed band cell in an off state), when the base station determines to switch on the secondary cell, the base station switches the secondary cell to the on state through the aforementioned physical layer signaling (L1 procedure). do. Or, the base station and the terminal recognizes the on state transition of the secondary cell.

Then, when the base station determines to switch off the secondary cell, the base station switches the secondary cell to the off state through the above-described physical layer signaling (L1 procedure). Or, the base station and the terminal recognizes the off state transition of the secondary cell.

The secondary cell activation operation or the secondary cell deactivation operation is as described above.

If the small cell is off, the small cell may transmit a cell discovery signal.

The terminal may perform off state small cell detection and / or off state small cell radio signal quality based on the cell discovery signal. Or, the terminal may not perform off state small cell detection and / or off state small cell measurement based on the cell discovery signal. Alternatively, the terminal may receive information indicating the small cell on state through the PCell. Alternatively, the terminal may perform an operation (for example, PCell monitoring) for receiving information indicating a small cell on state through the PCell.

The operation of the UE in the off-state of the above-described small cell may be performed only when the on-state cell is switched off through the L1 procedure or when the UE recognizes the off-state, or always in the off-cell. It may be.

Hereinafter, a method of measuring the cell discovery signal received from the small cell in the off state in the off state briefly described in each of the above embodiments will be described in detail.

단말의 셀 디스커버리 신호 측정Measurement of cell discovery signal of terminal

Small cell on / off may be provided in an dense mall cell deployment. When the small cell is off, the small cell may transmit a cell discovery signal. Unlike the CRS transmitted every subframe, the cell discovery signal transmitted when the small cell is turned off is transmitted in the limited subframe.

The base station may provide the terminal with information necessary for performing small cell discovery or for performing cell discovery signal based channel state measurement. For example, the base station may transmit measurement configuration information for measuring the cell discovery signal to the terminal. The measurement configuration information may include at least timing related information of the cell discovery signal (s). For example, the measurement configuration information may include information about a period of the cell discovery signal. As another example, the measurement configuration information may include cell discovery signal offset information indicating a first subframe in which each cell discovery signal occurs in one SFN (or radio frame or specific SFN number). As another example, the measurement configuration information may include duration information in which reception of the cell discovery signal is continued. As another example, the measurement configuration information may include timer information for terminating the cell discovery signal based measurement.

In order for the UE to detect / detect a cell or measure a channel state based on a cell discovery signal transmitted in a limited subframe, the UE acquires a downlink synchronization signal of the corresponding cell to obtain a first measurement sample and the cell discovery signal is The cell may be remeasured according to the pattern (or period) transmitted. The synchronization signal and the cell discovery signal of the small cell set to the off state may be transmitted in one subframe. Alternatively, the synchronization signal and the cell discovery signal of the small cell set to the off state may be transmitted at regular subframe intervals. Alternatively, the synchronization signal and the cell discovery signal may be transmitted through specific subframes in a specific radio frame of the small cell set to the off state.

Different small cells may have different cell discovery signal periods or patterns. When the small cells are densely constructed or when a plurality of small cells are constructed, the terminal may perform cell discovery signal measurement on different small cells in an off state. In order for the UE to perform cell discovery signal measurement for different small cells, when the UE performs measurement on all received cell discovery signals according to the cell discovery signal period or pattern of each small cell, power consumption of the UE is increased. Can cause problems.

Accordingly, the following method may be used as a method for the UE to efficiently perform cell discovery signal measurement for different small cells.

1) Configure the cell discovery signal measurement end timer

When the small cell is set to the off state, the small cell may transmit a cell discovery signal.

The UE may perform measurement based on the cell discovery signal through the small cell in the off state.

The base station configures a small cell in the terminal (or configures a small cell supporting the on / off function in the terminal or configures a cell discovery signal measurement for the small cell supporting the on / off function in the terminal or When configuring small cell discovery and cell discovery signal based measurement at the terminal, when providing an indication indicating the small cell off state or when the small cell is turned off), based on the cell discovery signal at the terminal You can configure, set, or start a measurement takeover timer. The cell discovery signal based measurement execution end timer may have a different timer value for each cell. Alternatively, the cell discovery signal based measurement execution end timer may be a terminal specific timer value.

The cell discovery signal based measurement performing end timer may be configured or started or restarted by the RRC signal. Alternatively, the cell discovery signal based measurement execution end timer may be configured or started or restarted by MAC signaling. Alternatively, the cell discovery signal based measurement execution end timer may be configured or started or restarted by L1 signaling (eg, a physical layer control channel).

The terminal may maintain a cell discovery signal based measurement end timer for each small cell in the off state.

When the cell discovery signal based measurement end timer expires, the terminal does not perform the cell discovery signal based measurement.

If the cell discovery signal-based measurement is performed before the end of the cell discovery signal-based measurement execution timer expires (or, if the UE is provided with an indication indicating the small cell off state or if the small cell receives the information that is switched off) The UE may restart the cell discovery signal based measurement execution end timer.

If the small cell is turned on before the cell discovery signal based measurement end timer expires, the cell discovery signal based measurement end timer may be stopped, released, or expired.

2) Configure the same cell discovery signal period or pattern in the same base station

When the small cell is turned off, the small cell may transmit a cell discovery signal.

The base station configures a small cell in the terminal (or configures a small cell supporting the on / off function in the terminal or configures a cell discovery signal measurement for the small cell supporting the on / off function in the terminal or When configuring small cell discovery and cell discovery signal based measurement at the terminal, or when providing an indication indicating the small cell off state to the terminal or when the small cell is turned off), the small in the off state at the terminal Information necessary for performing cell discovery or for performing cell discovery signal based measurement may be provided.

In order to reduce the power consumption of the terminal, the base station uses a cell transmission signal or a cell discovery signal of cells included in a cell group associated with the base station, cells provided by one base station, or all or some cells controlled by the same base station scheduler. It can be controlled to transmit through.

For example, cell discovery signal transmission cycles or patterns of cells in a base station having different frequencies may be transmitted in the same manner, and the UE may perform cell discovery signal measurement for each cell in an OFF state in the same subframe.

As another example, the cell discovery signal transmission period or pattern of the cells in the base station having the same frequency is transmitted in the same manner, but the cell discovery signal transmission of each cell is given a constant offset value so that the UE is turned off with a subframe difference as much as the offset. The cell discovery signal measurement may be performed for each cell.

As another example, the cell discovery signal transmission cycle or pattern of the cells in the base station belonging to the same timing advance group is transmitted in the same manner, and the UE may perform cell discovery signal measurement for each cell in the OFF state in the same subframe. Can be.

As another example, the cell discovery signal transmission cycle or pattern of the cells in the base station belonging to the same timing advance group is transmitted in the same manner, but the terminal is provided with a sub offset difference as much as the offset by giving a constant offset value to the cell discovery signal transmission of each cell. For example, the cell discovery signal measurement may be performed for each cell in the off state.

As another example, the base station may configure a cell discovery signal transmission period or pattern of the same cell group or the same timing advance group in the terminal.

As another example, the base station configures the cell discovery signal transmission period or pattern for each cell group or another timing advance group in a cell group or timing advance group unit, wherein the cell discovery signal transmission period or pattern is different or the same cell discovery is performed. The terminal may be configured by different offset values in the signal transmission period or pattern.

3) Configure the cell discovery signal period or pattern differently according to the state of the cell or configure the cell discovery signal transmission period and the cell discovery signal measurement period differently

The base station configures a small cell in the terminal (or configures a small cell supporting the on / off function in the terminal or configures a cell discovery signal measurement for the small cell supporting the on / off function in the terminal or When configuring small cell discovery and cell discovery signal based measurement at the terminal, or when providing an indication indicating the small cell off state to the terminal or when the small cell is turned off), the small in the off state at the terminal Information necessary for performing cell discovery or for performing cell discovery signal based measurement may be provided to the terminal.

In order to reduce power consumption of the terminal, the base station may configure a cell discovery signal transmission period or pattern differently according to the cell state.

For example, the UE may perform the measurement based on the CRS transmitted every subframe in the on state. Accordingly, the base station may not transmit the cell discovery signal when the small cell is on or transmit the cell discovery signal with a longer transmission period or pattern than the off state.

As another example, the base station may transmit the cell discovery signal in a specific cell discovery signal transmission period or pattern regardless of the on / off state of the small cell (or for the off state small cell). When the base station is in the off state of the small cell, the base station may transmit information for performing measurement or reporting at a longer period than the on state to the terminal. The UE may perform measurement or reporting based on the cell discovery signal at a longer period.

As another example, even when the small cell is configured in the terminal even in the off state, it may be necessary for the terminal to perform a measurement in a longer period or a shorter period than in the case where the small cell is not configured in the terminal. For example, when the small cell frequency in the off state is different from the frequency of the serving cell (s) configured in the terminal, the base station measures the intra frequency measurement based on the cell discovery signal based on the off state small cell in the off state. The small cell may be performed in a shorter period or a longer period as compared to the unconfigured cell discovery signal based inter frequency measurement. Therefore, when the small cell in the off state is configured in one or more terminals, the base station may set the cell discovery signal transmission period or pattern to a shorter transmission period or pattern than when the small cell in the off state is not configured in any terminal. . The base station may transmit the indication information for this to the terminal, the terminal may perform the measurement based on the cell discovery signal using this.

As another example, even in the off state, when the small cell is configured in the terminal, the terminal may need to perform the measurement in a longer period or a shorter period than in the case where the small cell is not configured in the terminal. For example, when the small cell frequency in the off state is different from the frequency of the serving cell (s) configured in the current terminal, the base station makes the cell discovery signal based intra frequency measurement in the off state small cell configured in the off state small state. The cell may be controlled to be performed in a shorter period or a longer period than the cell discovery signal based inter frequency measurement. However, the base station may transmit the cell discovery signal in a specific cell discovery signal transmission period or pattern regardless of whether the small cell is configured in one or more terminals in the off state (or regardless of the state of the small cell). The base station may transmit configuration / indication information for performing measurement or reporting to a terminal in a shorter or longer period, depending on the off-state small cell configured in the terminal. The UE may perform the cell discovery signal based measurement in a shorter or longer period.

As another example, even when the small cell is in the off state, when the small cell is configured to be activated in the terminal, the terminal needs to perform measurement in a longer period or a shorter period than when the small cell is configured in the inactive state. There may be. Therefore, when the small cell is activated in one or more terminals in the off state, the base station may set the cell discovery signal transmission period or pattern to a shorter period or pattern than when the small cell in the off state is not activated in any terminal. Meanwhile, the base station may transmit configuration or indication information for a period or pattern of the cell discovery signal to the terminal and transmit the measurement, and the terminal may perform measurement based on the cell discovery signal using the configuration or indication information.

As another example, when the small cell is activated in the terminal even when the small cell is in the off state, the terminal needs to perform the cell discovery signal measurement in a longer period or a shorter period than when the small cell is not activated. Can be. However, the base station may transmit the cell discovery signal in a specific cell discovery signal transmission period or pattern regardless of whether the small cell is activated to one or more terminals in the off state or the state of the small cell. The base station may transmit configuration or indication information for performing longer period or shorter period measurement or reporting according to the state of the off-state small cell to the terminal, and the terminal may measure the cell discovery signal based measurement using the configuration or indication information Can be performed in shorter or longer periods.

As another example, when the small cell is in the off state, the UE may perform measurement or reporting with a period longer than a specific cell discovery signal transmission period or pattern transmitted through the off state small cell. In addition to the cell discovery signal transmission period or pattern of the off-state small cell, the base station may transmit information including information for performing measurement or reporting with a longer period for performing the cell discovery signal based measurement for each terminal. have. The UE may perform the cell discovery signal based measurement using a longer period than the cell discovery signal transmission period or pattern using the above information.

The base station may be configured by distributing the cell discovery signal-based measurement period performed for each terminal in the cell discovery signal transmission period.

For example, when the cell discovery signal transmission period is T_Period and the cell discovery signal measurement period configured in the terminal is M_Period, M_Period = n * T_Period, n may be a natural number. Specifically, when M = Period = 2 * T_Period, the measurement period is distributed to two terminal groups of odd T_Period (1, 3, 5, ... and even T_Period (2, 4, 6, ...). Therefore, when M_Period = n * T_Period, the measurement period can be distributed to up to n groups.

For example, the aforementioned cell discovery signal transmission period may be timing related information of discovery signal (s) required for performing small cell discovery or for performing cell discovery signal based measurement. For example, the cell discovery signal pattern described above may be a cell discovery signal offset and / or transmission of a cell discovery signal indicating a first subframe in which each cell discovery signal occurs in one SFN (or radio frame or a specific SFN number). It may include duration information.

As another example, the above-described cell discovery signal measurement period may be measurement gap information for inter-frequency measurement based on cell discovery signal when the frequency of the off state small cell is different from the frequency of the serving cell (s) currently configured in the terminal. In the prior art, the measurement gap is a terminal-specific value. In this case, for inter frequency or inter RAT measurement of the terminal, the base station does not schedule for uplink or downlink transmission to the terminal in the measurement gap. If the measurement gaps of all UEs in the specific cell are the same, a problem may occur in which resources in the corresponding measurement gap cannot be used. Therefore, the conventional measurement gap could be dispersed for each terminal through a gap offset value in the measurement gap period.

In the off-state small cell, the cell discovery signal transmission period or pattern may be fixed for each cell. When there are a plurality of off state small cells, the cell discovery signal transmission period or pattern between cells may be the same or may be different. If all UEs have the same measurement gap to measure the off-state small cell (s) based on the cell discovery signal, it may be inefficient because resources in the corresponding measurement gap cannot be used. In addition, measuring the cell discovery signal in every cell discovery signal transmission period or pattern may increase the power consumption of the terminal. This problem may occur more seriously if the DRX is configured and the terminal is in an inactive state. When the cell discovery signal measurement period and the cell discovery signal transmission period are divided and used for each terminal group, the measurement gap may be divided into n terminal groups.

For example, if the cell discovery signal transmission period is 10ms, when the period of the measurement gap is 40ms, select only within 4 values (for example, 0, 10, 20, 30) as the gap offset value. Can be. If the cell discovery signal transmission period is 40ms, it may be selected only within two values (eg, 0, 40) as a gap offset value when the period of the measurement gap is 80ms.

As another example, the aforementioned cell discovery signal measurement period may be measurement cycle information for measuring a secondary cell based on the cell discovery signal when the small cell in the off state is configured in the terminal and the small cell in the off state is the serving cell. For example, measurement cycle information for secondary cell measurement based on cell discovery signal may be included as a new information element (for example, MeasCycleOffSCell-r12 or MeasCycleDRS-r12) in the MeasObjectEUTRA field included in the measurement configuration or the measurement configuration. The measurement cycle information for the secondary cell measurement based on the cell discovery signal may have a value longer than the cell discovery signal transmission period (for example, n times the DRS transmission period and n is an integer). Alternatively, the measurement cycle information for the secondary cell measurement based on the cell discovery signal may have the same value as the measurement cycle information value for the secondary cell measurement in the inactive standard state. For example, if the cell discovery signal transmission period is 10 ms, the measurement cycle information for the secondary cell measurement based on the cell discovery signal may be selected from one or more of sf160, sf320, sf640, and sf1280. For another example, if the transmission period is 40 ms, the measurement cycle information for the secondary cell measurement based on the cell discovery signal may be selected from one or more of sf160, sf320, sf640, and sf1280.

As described above, for example, a method of distributing a cell discovery signal measurement period of an inter frequency measurement gap for each terminal or making an intra frequency measurement cycle an n times a transmission period is not limited to the described example.

The above-described methods described above in the present specification may be used independently or in combination of one or more methods.

셀 디스커버리 신호 측정과 CRS 측정 및 리포팅Cell Discovery Signal Measurement and CRS Measurement and Reporting

When the small cell is turned off, the small cell may transmit a cell discovery signal. When the small cell is turned on, the small cell may not transmit the cell discovery signal.

Alternatively, when the small cell is turned off, the small cell may transmit a cell discovery signal. When the small cell is turned on, the small cell may transmit a cell discovery signal.

As an example, if the small cell transmits a cell discovery signal and the terminal is configured for the cell discovery signal measurement configuration and the CRS measurement configuration, the terminal may perform both the cell discovery signal based measurement and the CRS based measurement. In addition, the UE may perform both cell discovery signal based measurement reporting and CRS based measurement reporting. Alternatively, the UE may perform only one measurement reporting of cell discovery signal based measurement reporting and CRS based measurement reporting. This may be determined by the terminal itself, or may configure reporting to take precedence when the base station is configured to measure.

As another example, if the cell discovery signal is transmitted while the small cell is on, and the UE is configured with the cell discovery signal measurement configuration and the CRS measurement configuration, the UE performs only one of the cell discovery signal based measurement and the CRS based measurement. can do. This may be determined by the terminal itself, or may configure a measurement to be prioritized when the base station configures the measurement.

As described above, the present invention provides an effect of reducing the power consumption of the terminal by allowing the terminal to efficiently perform the RRM measurement and report it to the base station based on the cell discovery signal transmitted only within a limited subframe. do. In addition, the present invention provides an effect of preventing a signal interference between the cells and waste of power consumption of the entire system by adding a cell supporting an on / off function as a secondary cell in an environment where a plurality of small cells are deployed. In addition, the present invention has an effect of preventing the ambiguity of the activation operation of the cell supporting the on / off function by defining a method for activating or deactivating the secondary cell when the terminal adds a cell supporting the on / off function. to provide. In addition, the present invention provides an effect of processing a large amount of data at high speed by providing a specific method capable of transmitting and receiving data as needed in parallel with the on / off operation and the activation operation.

The configuration of a terminal and a base station in which both of the present invention described above can be performed will be described once again with reference to the drawings.

9, a user terminal 900 according to another embodiment of the present invention includes a receiver 930, a controller 910, and a transmitter 920.

The terminal 900 of the present invention includes a receiver 930 for receiving measurement configuration information for measuring a cell discovery signal and a transmitter for transmitting radio signal quality measurement information of a cell measured based on the measurement configuration information and the cell discovery signal ( The controller 910 may further configure a cell associated with the cell discovery signal as a secondary cell based on the higher layer signal.

Also, the receiver 930 may receive a physical layer signal including information indicating whether the secondary cell is activated. In addition, the controller 910 may control the activation or deactivation operation of the terminal for the secondary cell based on the physical layer signal. For example, when the physical layer signal includes information indicating the on state of the secondary cell, the controller 910 may control a part of the secondary cell activation or the secondary cell activation to be performed for the secondary cell. have. In this case, the secondary cell activation operation may include at least one of an uplink reference signal transmission operation on the secondary cell, a channel state information reporting transmission operation for the secondary cell, a control channel monitoring operation on the secondary cell, and a control channel monitoring operation for the secondary cell. It includes.

In addition, when the physical layer signal includes information indicating the off state of the secondary cell, the controller 910 may control to perform a deactivation operation or a part of the secondary deactivation operation of the secondary cell. The secondary cell deactivation operation does not transmit an uplink reference signal on the secondary cell, does not transmit an uplink shared channel on the secondary cell, does not transmit a random access channel on the secondary cell, and reports channel state information for the secondary cell. This means that the control is performed such that at least one of not performing control channel monitoring on the secondary cell and not performing control channel monitoring on the secondary cell is performed. .

In addition, the controller 910 may control the operation of the terminal for operating each of the above-described embodiments of the present invention.

The receiver 930 receives downlink control information, data, and a message from a base station through a corresponding channel. The transmitter 920 transmits uplink control information, data, and a message to a base station through a corresponding channel.

Referring to FIG. 10, the base station 1000 according to another embodiment of the present invention includes a controller 1010, a transmitter 1020, and a receiver 1030.

The base station 1000 according to the present invention includes a receiver 1030 and a cell discovery signal for receiving radio signal quality measurement information of a cell associated with a cell discovery signal measured based on measurement configuration information for measuring a cell discovery signal and a cell discovery signal. The transmitter 1020 may transmit a higher layer signal including information for controlling the terminal to additionally configure the cell associated with the secondary cell.

In addition, the transmitter 1020 may transmit a physical layer signal including information indicating an on state or an off state of the secondary cell. For example, a physical layer signal including information indicating an on state of a secondary cell may be configured to allow a terminal receiving the physical layer signal to perform a secondary cell activation operation or a part of a secondary cell activation operation for the secondary cell. To control. Alternatively, the physical layer signal including information indicating an off state of the secondary cell may be controlled such that a terminal receiving the physical layer signal performs a part of a secondary cell deactivation operation or a secondary cell deactivation operation of the terminal with respect to the secondary cell. It is for.

The transmitter 1020 may transmit measurement configuration information including information necessary for measuring and searching for a cell discovery signal.

The controller 1010 controls the on / off state determination of the small cell required to carry out the above-described present invention, generation of a signal transmitted to the terminal, and overall operation of the base station required to perform each of the above-described embodiments. .

In addition, the transmitter 1020 and the receiver 1030 are used to transmit and receive signals, messages, and data necessary for carrying out the present invention described above.

The above description is merely illustrative of the technical idea of the present invention, and those skilled in the art to which the present invention pertains may make various modifications and changes without departing from the essential characteristics of the present invention. Therefore, the embodiments disclosed in the present invention are not intended to limit the technical spirit of the present invention but to describe the present invention, and the scope of the technical idea of the present invention is not limited by these embodiments. The protection scope of the present invention should be interpreted by the following claims, and all technical ideas within the equivalent scope should be interpreted as being included in the scope of the present invention.

CROSS-REFERENCE TO RELATED APPLICATIONCROSS-REFERENCE TO RELATED APPLICATION

This patent application is filed with Korea Patent Application No. 10-2014-0038471 filed on April 01, 2014 and Korea Patent Application No. 10-2014-0046510 filed on April 18, 2014, and March 2015 Patent Application No. 10-2015-0034719, filed with Korea on 13th, claims priority under US Patent Act 119 (a) (35 USC § 119 (a)), all of which are hereby incorporated by reference. Incorporated into the application. In addition, if this patent application claims priority for the same reason for countries other than the United States, all its contents are incorporated into this patent application by reference.

Claims

In the method for the terminal to control the secondary cell operation,

Receiving measurement configuration information for measuring a cell discovery signal;

Transmitting measurement information of a cell measured based on the measurement configuration information and the cell discovery signal; And

And configuring a cell associated with the cell discovery signal as a secondary cell based on a higher layer signal.
The method of claim 1,

Receiving a physical layer signal including information indicating an on state or an off state of the secondary cell; And

And controlling an activation operation or a deactivation operation of the terminal with respect to the secondary cell based on the physical layer signal.
The method of claim 2,

When the physical layer signal includes information indicating the on state of the secondary cell,

A method of controlling a secondary cell activation operation or a portion of a secondary cell activation operation of a terminal to the secondary cell is performed
The method of claim 3, wherein

The secondary cell activation operation,

Operation of transmitting an uplink reference signal (SRS) on the secondary cell, channel state information (CSI) reporting transmission operation for the secondary cell, control channel monitoring operation on the secondary cell, and control channel for the secondary cell A method comprising one or more of the monitoring operations.
The method of claim 2,

When the physical layer signal includes information indicating the off state of the secondary cell,

And controlling a part of a terminal deactivation operation or a secondary deactivation operation on the secondary cell.
The method of claim 5,

The secondary cell deactivation operation,

No uplink reference signal (SRS) on the secondary cell, no uplink shared channel on the secondary cell, no random access channel on the secondary cell, channel state information for the secondary cell (Channel State Information, And controlling at least one of CSI) non-reporting, control channel non-monitoring on the secondary cell, and control channel non-monitoring for the secondary cell.
In the method for the base station to control the operation of the secondary cell of the terminal,

Receiving measurement configuration information for measuring a cell discovery signal and measurement information of a cell associated with the cell discovery signal measured based on the cell discovery signal; And

And transmitting a higher layer signal including information for controlling the terminal to further configure a cell associated with the cell discovery signal as a secondary cell.
The method of claim 7, wherein

And transmitting a physical layer signal including information indicating whether the secondary cell is in an on state or an off state.
The method of claim 8,

The physical layer signal,

And information indicating an on state of the secondary cell for controlling the terminal receiving the physical layer signal to perform a part of a secondary cell activation or a secondary cell activation of the terminal with respect to the secondary cell.
The method of claim 8,

The physical layer signal,

And information indicating an off state of the secondary cell for controlling the terminal receiving the physical layer signal to perform a part of a secondary cell deactivation operation or a secondary deactivation operation of the terminal with respect to the secondary cell.
In the terminal for controlling the operation of the secondary cell,

A receiver configured to receive measurement configuration information for measuring a cell discovery signal;

A transmitter for transmitting measurement information of a cell measured based on the measurement configuration information and the cell discovery signal; And

And a control unit configured to further configure a cell associated with the cell discovery signal as a secondary cell based on an upper layer signal.
The method of claim 11,

The receiving unit,

Receiving a physical layer signal including information indicating an on state or an off state of the secondary cell;

The control unit,

A terminal for controlling the activation operation or deactivation operation of the terminal for the secondary cell based on the physical layer signal.
The method of claim 12,

The control unit,

When the physical layer signal includes information indicating the on state of the secondary cell,

A terminal for controlling a secondary cell activation operation or a portion of a secondary cell activation operation of the terminal for the secondary cell.
The method of claim 13,

The secondary cell activation operation,

Operation of transmitting a Sounding Reference Signal (SRS) on the secondary cell, Channel State Information CSI reporting transmission operation for the secondary cell, Control channel monitoring operation on the secondary cell, and Control channel monitoring for the secondary cell Terminal comprising one or more of the operations.
The method of claim 12,

The control unit,

When the physical layer signal includes information indicating the off state of the secondary cell,

A terminal for controlling a deactivation operation or a part of a secondary deactivation operation of the terminal with respect to the secondary cell.
The method of claim 15,

The secondary cell deactivation operation,

No uplink reference signal (SRS) on the secondary cell, no uplink shared channel on the secondary cell, no random access channel on the secondary cell, channel state information for the secondary cell (CSI: Channel State) Information) A terminal comprising an operation for controlling so that at least one of non-reporting, control channel non-monitoring on the secondary cell and control channel non-monitoring for the secondary cell is set.
In the base station for controlling the operation of the secondary cell of the terminal,

A receiver configured to receive measurement configuration information for measuring a cell discovery signal and measurement information of a cell associated with the cell discovery signal measured based on the cell discovery signal; And

And a transmitter configured to transmit an upper layer signal including information for controlling the terminal to additionally configure a cell associated with the cell discovery signal as a secondary cell.
The method of claim 17,

The transmitting unit,

And a base station further transmitting a physical layer signal including information indicating an on state or an off state of the secondary cell.
The method of claim 18,

The physical layer signal,

And a base station including information indicating an on state of the secondary cell for controlling the terminal receiving the physical layer signal to perform a part of a secondary cell activation or a secondary cell activation of the terminal with respect to the secondary cell.
The method of claim 18,

The physical layer signal,

And a base station including information indicating an off state of the secondary cell for controlling the terminal receiving the physical layer signal to perform a part of a secondary cell deactivation operation or a secondary deactivation operation of the terminal with respect to the secondary cell.