WO2014098378A1

WO2014098378A1 - Method and device for transmitting and receiving epdcch in common search area

Info

Publication number: WO2014098378A1
Application number: PCT/KR2013/010471
Authority: WO
Inventors: 김종남
Original assignee: 주식회사 팬택
Priority date: 2012-12-20
Filing date: 2013-11-18
Publication date: 2014-06-26
Also published as: KR20140079967A

Abstract

The present invention relates to a method and a device for transmitting and receiving an Enhanced Physical Downlink Control Channel (EPDCCH) in a common search area. According to one embodiment, the method for transmitting an EPDCCH comprises: a step of transmitting, to a terminal, a Physical Broadcast Channel (PBCH) including a bitmap, which indicates a common search area for the EPDCCH in a resource block group, or combination index information; and a step of transmitting the EPDCCH to the terminal through the common search area.

Description

Method and apparatus for transmitting and receiving EPDCCH in common search space

The present invention relates to a method apparatus for transmitting and receiving an EPDCCH in a common search space.

According to the 3GPP LTE-Advanced standardization trend, various discussions on carriers are underway, and one of them is a new carrier type (NCT).

NCT is divided into Standalone NCT (S-NCT) and Non-standalone NCT (NS-NCT) types.In NCT, PDCCH (Physical Downlink Control Channel), PHICH (Physical HARQ Indicator Channel), PCFICH Control signals such as a physical control format indicator channel (CRS) and a cell-specific reference signal (CRS) may not be transmitted.

However, the UE transmits a MIB (Master Information Block), which is system information, through a PBCH (Physical Broadcast Channel) among control signals after the cell discovery process, and also through the data channel indicated through a common control channel, the system information SIB Information block). After the system information has been received and decoded, the UE can access the cell through a random-access process.

However, in the NCT, there is no PDCCH, and thus, a common search space (CSS) that can search for a PDCCH cannot be defined, and a common control channel can not be received through such a common search space. A problem may occur in the process of the terminal receiving and decoding the system information.

In one aspect, the present invention is to provide a method for transmitting and receiving indication information for a common search space that can search the EPDCCH indicating a data channel for providing system information.

In another aspect, the present invention is to provide a method for a base station and a terminal to transmit and receive an EPDCCH as a common control channel through a common search space.

According to an aspect of the present invention, in a method for transmitting an Enhanced Physical Downlink Control Channel (EPDCCH) by a base station, a common search space for transmitting the EPDCCH is provided in units of resource block groups. The present invention provides a method of transmitting an EPDCCH including transmitting a physical broadcast channel (PBCH) including an indication bitmap or combination index information to a terminal, and transmitting the EPDCCH to the terminal through the common search space.

According to another aspect of the present invention, in a method for a terminal to receive an Enhanced Physical Downlink Control Channel (EPDCCH), the terminal indicates a common search space for the EPDCCH in units of a resource block group. A method of receiving an EPDCCH includes receiving a physical broadcast channel (PBCH) including bitmap or combination index information from a base station, and receiving the EPDCCH from the base station by searching the common search space.

According to another aspect of the present invention, in a base station transmitting an Enhanced Physical Downlink Control Channel (EPDCCH), a bit indicating a common search space for the EPDCCH in units of a resource block group A base station including a control unit for generating map or combination index information and a transmitter for transmitting a physical broadcast channel (PBCH) including the bitmap or combination index information to a terminal and transmitting the EPDCCH to the terminal through the common search space. To provide.

According to another aspect of the present invention, in a terminal for receiving an Enhanced Physical Downlink Control Channel (EPDCCH), a bit indicating a common search space for the EPDCCH in units of a resource block group A terminal includes a PBCH receiver that receives a physical broadcast channel (PBCH) including map or combination index information from a base station, and an EPDCCH receiver that receives the EPDCCH from the base station by searching the common search space.

According to the present invention, a base station and a terminal may transmit / receive an EPDCCH necessary for acquiring system information through a common search space in a wireless communication system using NCT.

1 is a diagram schematically illustrating a wireless communication system to which embodiments are applied.

2 is a flowchart illustrating a process in which a terminal acquires synchronization with a base station and obtains system information.

3 is a diagram for a physical resource on which a PBCH is transmitted.

4 illustrates an example of a common search space and a ue-specific search space for two terminals.

FIG. 5 illustrates one resource block pair in the case of a normal cyclic prefix (CP) as an example of a structure of a downlink resource in a Long Term Evolution (LTE) or LTE-Advanced (LTE-A) system.

FIG. 6 illustrates an example of resource element (RE) mapping of a PRB (Physical Resource Block) pair EREG indexed with a symbolic reference cyclic shift with respect to one transmit antenna port (Cell-specific Reference Signal (CRS) port 0) It is also.

7 is an example of a resource block and a resource block group.

8 is an example of a resource block group according to Equation (1).

9 is another example of a resource block group according to Equation (1).

10 is a flowchart of an EPDCCH transmission method of a base station according to an embodiment of the present invention.

11 is a flowchart illustrating an EPDCCH reception method of a terminal according to an embodiment of the present invention.

12 is a block diagram of a base station according to an embodiment of the present invention.

13 is a block diagram of a terminal according to an 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.

In addition, in describing the component of this invention, terms, such as 1st, 2nd, A, B, (a), (b), can be used. These terms are only for distinguishing the components from other components, and the nature, order or order of the components are not limited by the terms. If a component is described as being "connected", "coupled" or "connected" to another component, that component may be directly connected to or connected to that other component, but there may be another configuration between each component. It is to be understood that the elements may be "connected", "coupled" or "connected".

The wireless communication system 100 is widely deployed to provide various communication services such as voice and packet data.

Referring to FIG. 1, the wireless communication system 100 includes a user equipment (UE) 110 and a base station 120 (BS).

In the present specification, the terminal 110 is a comprehensive concept of a user terminal in wireless communication, and includes a user equipment (WCDMA), a long term evolution (LTE), a long term evolution (LTE), a high speed packet access (HSPA), and the like. Equipment, of course, should be interpreted as including a mobile station (MS), a user terminal (UT), a subscriber station (SS), a wireless device, and the like in a global system for mobile communications (GSM). .

The terminal 110 may perform feedback of channel information described below, and provide an apparatus thereof.

The base station 120 or cell generally refers to a fixed station communicating with the terminal 110 and includes a Node-B, an evolved Node-B, and a Base Transceiver. It may be called other terms such as a System, an Access Point, a Relay Node, and the like.

The base station 120 may transmit a reference signal to the terminal 110, receive feedback of channel information from the terminal 110, and transmit data or signals using the channel information.

That is, in the present specification, the base station 120 or the cell should be interpreted in a comprehensive sense to indicate some areas covered by the base station controller (BSC) in the code division multiple access (CDMA), the node-B of the WCDMA, and the like. It is meant to cover all the various coverage areas such as megacell, macrocell, microcell, picocell, femtocell and relay node communication range.

In the present specification, the terminal 110 and the base station 120 are two transmitting and receiving entities used to implement the technology or the technical idea described in the present specification and are used in a comprehensive sense and are not limited by the terms or words specifically referred to. .

There is no limitation on the multiple access scheme applied to the wireless communication system 100. 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.

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.

One embodiment is applied to asynchronous wireless communication that evolves into Long Term Evolution (LTE) and LTE-advanced through GSM, WCDMA, HSPA, and synchronous wireless communication that evolves into CDMA, CDMA-2000 and Ultra Mobile Broadband (UMB). Can be. 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 wireless communication system 100 to which the embodiments are applied may support uplink and / or downlink HARQ (HARID), and may use a channel quality indicator (CQI) for link adaptation. In addition, multiple access schemes for downlink and uplink transmission may be different from each other. For example, downlink uses Orthogonal Frequency Division Multiple Access (OFDMA), and uplink uses Single Carrier-Frequency Division Multiple Access (SC-FDMA). ) Is the same as can be used.

Recently, various discussions have been made on a new carrier type (NCT).

These NCTs are classified into standalone NCT (S-NCT) and non-standalone NCT (NS-NCT) types, and in NCT, physical downlink control channel (PDCCH), physical HARQ indicator channel (PHICH), Control signals such as a physical control format indicator channel (PCFICH) and a cell-specific reference signal (CRS) may not be transmitted.

The non-standalone NCT refers to MIB (Master Information Block, hereinafter referred to as 'MIB') information and information transmitted through a common control channel (reference carrier), where the non-standalone NCT is transmitted along with the reference carrier However, the self-contained NCT must receive MIB information and information transmitted through a common control channel through the NCT. A situation in which a signal is transmitted and received through a new carrier type carrier is transmitted or received through an NCT, or in the form of transmitting or receiving an NCT. First, the MIB transmission and the common control channel transmission in the legacy carrier type will be described. Techniques used in the legacy carrier type can also be applied in the NCT. Therefore, the steps or functions included in the description of the MIB transmission and the common control channel transmission in the legacy carrier type may be used in the wireless communication system in which the NCT is used.

In order to communicate with the base station, the terminal goes through a step of acquiring synchronization with a cell (synchronization step) and a step of acquiring system information about the cell (system information acquiring step).

Referring to FIG. 2, the terminal and the base station achieve cell synchronization through a primary synchronization signal (P-SS) and a secondary synchronization signal (S-SS) (S210).

The UE detects the P-SS of the cell to know the 5ms timing of the cell, and can also know the position of the S-SS ahead of the P-SS. The UE knows the frame timing through the S-SS. By knowing the frame timing through this information, the terminal and the base station are synchronized.

In addition, the UE knows the cell ID group through the S-SS, and the cell ID value belonging to the cell ID group through the P-SS.

When the terminal acquires the frame timing and the cell ID through the synchronization step (S210), the terminal can then obtain the system information.

System information may be transmitted through two different transport channels.

The master information block (MIB) may be transmitted through a broadcasting channel (BCH), and the system information block (SIB) may be transmitted through a downlink shared channel (DL-SCH).

Referring back to FIG. 2, the base station transmits the MIB to the terminal through a physical broadcasting channel (PBCH) (S220).

Table 1

Table 1 shows the structure and information of the MIB.

Referring to Table 1, the MIB includes information indicating downlink bandwidth and includes PHICH (Physical HARQ Indicator Channel) configuration information. In order to receive the SIB through the Physical Downlink Shared Channel (PDSCH), the PDCCH, which is control information, must be received. And, in order to receive such a PDCCH, it is necessary to know the PHICH configuration. In addition, the MIB may include information related to the system frame number.

With continued reference to Table 1, the MIB has 10 spare bits that do not contain other information.

3 is a diagram for a physical resource on which a PBCH is transmitted.

The 24-bit MIB forms a 40-bit information body with the addition of 16-bit cyclic redundancy check (CRC). The information body thus configured is allocated to the PBCH transmitted in a 40 ms period through coding and rate-matching. The MIB allocated to the PBCH is transmitted using 6RB (Resource Block) around the center frequency of the carrier as shown in FIG. 3 so that detection can be performed regardless of the system band allocated to the UE.

After the transmission and reception for the MIB, the base station and the terminal transmits and receives the SIB.

SIB can be classified into eight or more different information according to the type, SIB1 (System Information Block 1, hereinafter referred to as 'SIB1') includes information related to whether the terminal can be located in the cell. The SIB2 (System Information Block 2, hereinafter referred to as 'SIB2') includes information required for the UE to access the cell. In addition, SIB3 (System Information Block 3, hereinafter referred to as 'SIB3') includes information related to cell reselection, and SIB4 to SIB8 include information related to neighboring cells on the same carrier.

The main parts of the system information included in the SIBs are transmitted through the PDSCH. The presence or absence of system information on the PDSCH in the subframe is known by transmission of the PDCCH indicated by the System Information-Radio Network Temporary Identifier (SI-RNTI). The PDCCH includes information on a transmission format and physical resources used for transmitting system information.

The PDCCH related to dynamic scheduling for such system information should be transmitted to a certain group of terminals or all terminals of the base station. A common search space may be defined for this PDCCH. All terminals in the cell search for control information (PDCCH) by examining control channel elements (CCEs) in the common search space.

Referring to FIG. 4, a common search space is defined in common between two terminals, and a terminal-specific search space of a different area is defined for each terminal. As shown in FIG. 4, the common search space is limited to a space having a predetermined size according to an aggregation level from the control channel element 0 (CCE) 0.

The UE may receive control information for SIB reception through the PDCCH transmitted through the common search space.

MIB transmission in the legacy carrier type and PDCCH transmission through a common search space have been described. However, such a PDCCH may not be used in a new carrier type (NCT). Therefore, it should be provided in a separate method that can transmit and receive control information for SIB reception.

The present invention provides a method for transmitting and receiving an Enhanced Physical Downlink Control Channel (EPDCCH) through a common search space so that control information for SIB reception in the NCT can be transmitted and received.

As the control region disappears from the NCT, an EPDCCH for transmitting control information in the data region has been introduced.

Referring to FIG. 5, in the case of a normal CP, one resource block pair includes 14 OFDM symbols (l = 0 to 13) and 12 subcarriers (k = 0 to 11). In the example of FIG. 5, a region (l = 0 to 2) consisting of three OFDM symbols in front of fourteen OFDM symbols belonging to one resource block pair is represented by a physical control format information channel (PCFICH) and a physical hybrid ARQ indicator (PHICH). A control region 510 allocated for a control channel such as CHannel), a physical downlink control channel (PDCCH), etc., and the remaining regions (l = 3 to 13) are allocated for a data channel such as a physical downlink shared channel (PDSCH). It may be a data area 520. Although three OFDM symbols are shown in FIG. 5 for the control region 510, it is possible to allocate one, two, three, four OFDM symbols for the control region 510. The size information of the OFDM symbol of the control region 510 may be transmitted through the PCFICH.

The resources of the control area 510 reduce the resources of the data area 520 used for data transmission as overhead of the system. In an OFDM-based LTE system, one resource block pair consists of 14 or 12 OFDM symbols, of which up to three OFDM symbols are used for the control region 510 and the remaining OFDM symbols are used for the data region 520. I use it. Meanwhile, in the LTE-A system capable of transmitting data to more users, system capacity increase may be limited due to the resources of the conventional limited control region 510. Therefore, an increase in control channel resources is inevitable, and thus a control channel transmission / reception method for multiple users using a spatial division multiplexing technique in the data region 520 may be considered. This method is to transmit and receive a control channel in the data area 520. For example, the control channel transmitted in the data region 520 may be called EPDCCH (Extended PDCCH or Enhanced PDCCH), but is not limited thereto.

In a wireless communication system such as an existing 3GPP LTE / LTE-A rel-8 / 9/10 system, all terminals are used to receive downlink downlink control information (DCI). It depends on the Physical Downlink Control Channel (PDCCH) transmitted through 1 to 3 OFDM symbols (system band> 10 PRBs) or 2 to 4 OFDM symbols (system band ≤ 10 PRBs) in front of the frame. The basic unit of PDCCH transmission for any terminal is a control channel element (CCE), and one CCE is composed of nine resource element groups (REGs). One REG is included in REs except for PCFICH, which is another physical channel present in the PDCCH region of the corresponding downlink subframe, and resource elements (REs) to which a PHICH and a cell-specific reference signal (CRS) are transmitted. 4 consecutive REs on the frequency axis.

EPDCCH, which is newly introduced in 3GPP LTE / LTE-A release 11 and subsequent systems, is transmitted through a PDSCH region unlike the legacy PDCCH, and is configured to receive a UE configured to receive DCI (Downlink Control Information) through the EPDCCH. For this purpose, it is defined to assign up to K (K = 1 or 2) EPDCCH sets composed of M group of M PRBs (M = 2, 4 or 8). . In addition, each EPDCCH set configured for a certain UE may have a different K value.

According to the EPDCCH transmission type, the EPDCCH set may be a localized type or a distributed type. The aforementioned M may be 1 or 2n (n = 1, 2, 3, 4, 5), but is not limited thereto. Meanwhile, M may be 2, 4, 8, or 16 in a distributed form, but is not limited thereto.

On the other hand, K (K ≥ 1) EPDCCH sets may be allocated to one UE. Since each EPDCCH set is distributed type or centralized type, KL centralized type EPDCCH and KD distributed for one UE. EPDCCH of type can be allocated. In other words, KL + KD = K. For example, when K is 2, KL may be one of 0,1,2 and KD may be one of 2,1,0.

In order to map an EPDCCH transmission resource for an arbitrary UE, EREG (Enhanced REG) / ECCE (Enhanced CCE) may be introduced into the EPDCCH corresponding to the concept of REG and CCE of the conventional PDCCH.

According to the newly introduced EREG / ECCE, not only the frame structure type, subframe configuration, and cyclic prefix length, but also the legacy PDCCH control for one PRB pair constituting each EPDCCH set In the PRB pair, regardless of the existence of the reference signal (for example, CRS, CSI-RS, PRS, etc.) except for the region size and DM-RS (Demodulation Reference Signals, hereinafter referred to as 'DM-RS') A total of 16 EREGs can be configured from EREG # 0 to EREG # 15.

Specifically, in case of normal CP for one PRB pair constituting any EPDCCH set, 16 numbers for 144 REs except for 24 REs for DM-RS among 12 x 14 = 168 REs in total EREG indexing from 0 to 15 can be performed in a frequency first and then time manner. In the case of the extended CP, a frequency first method likewise for 16 REs except for 16 REs for DM-RS among 12 x 12 = 144 REs constituting one PRB pair is frequency first. and then time manner) can be indexed EREG from 0 to 15.

FIG. 6 illustrates an example of resource element (RE) mapping of an EREG indexed physical resource block (PRB) pair with respect to one transmit antenna port (Cell-specific reference signal (CRS) port 0). In FIG. 6, portions indicated by hatches and not indicated by the numbers indicate REs used for DM-RS, and portions indicated by numbers indicated by grids and hatched indicate the REs to which the CRS is transmitted. 6 illustrates that the DM-RS and the CRS are allocated to the PRB and transmitted, but the DM-RS and / or the CRS may not be transmitted.

Referring to FIG. 6, the EREG is indexed in a frequency-prioritized manner to numbers from 0 to 15. In FIG. 6, REs having the same index are grouped into one EREG. Therefore, a total of 16 EREGs from EREG # 0 to EREG # 15 are allocated to one PRB pair. 6 illustrates an example of a PRB pair of a normal CP, but in the same manner, 16 EREGs are allocated to EREG # 0 to EREG # 15 for the PRB pair of the extended CP.

According to Fig. 6, each of the EREG # 0, EREG # 1,... Set in one PRB pair. , EREG # 15 may consist of 9 REs each.

ECCE, which is a basic unit of EPDCCH transmission, may be composed of N EREGs according to subframe type and CP length, respectively. Specifically, the N value may be determined as follows.

First, N = 4 may be set for 3, 4, and 8 of a normal subframe corresponding to a normal CP and a special subframe corresponding to a normal CP. That is, in this case, four ECCEs may be configured with four EREGs for each of 16 EREGs constituting one PRB pair.

In another case, the normal subframe corresponding to the extended CP, the

special subframes

1, 2, 6, 7 and 9 corresponding to the normal CP, and the

special subframes

1, 2, 3, corresponding to the extended CP, N and 8 can be set for 5 and 6. In this case, two ECCEs may be configured with eight EREGs for each of 16 EREGs constituting one PRB pair.

In the PRB pair of any EPDCCH set, the 1st ECCE consists of EREG # 0, EREG # 4, EREG # 8, and EREG # 12, and the 2nd ECCE consists of EREG # 1, EREG # 5, EREG # 9, and EREG # 13. The 3rd ECCE may consist of EREG # 2, EREG # 6, EREG # 10, and EREG # 14, and the 4th ECCE may include EREG # 3, EREG # 7, EREG # 11, and EREG # 15. The EREGs constituting the ECCE may be in the same subframe or different subframes according to the transmission type of the EPDCCH.

The present invention provides a method for transmitting and receiving an Enhanced Physical Downlink Control Channel (EPDCCH) through a common search space so that control information for SIB reception can be transmitted and received in the NCT, the PDCCH in the legacy carrier type is removed. A method of allocating a common search space for an EPDCCH is provided.

For example, in the standalone NCT, since the NCT may be used as a primary cell (hereinafter, referred to as a 'PCell'), transmission of a PBCH may be required to acquire MIB information about the NCT. In addition, since the NCT cannot transmit the common control channel through the PDCCH, transmission of the common control channel through the EPDCCH is required, and a method of indicating a common search space through which the EPDCCH is transmitted is required.

The present invention provides a method of transmitting and receiving common search space allocation (directive) information for transmission of MIB information and EPDCCH through the PBCH transmitted in the NCT.

As described above in Table 1, Rel-8 PBCH is used to transmit information on system bandwidth, PHICH setting, and system frame number. And a 10-bit spare bit transmission is used together which is not used here. Prior to Rel-12, the unused 10-bit spare bit is not included in the information transmitted on the PBCH and is ignored.

The present invention provides a common search space resource allocation (directive) method for EPDCCH transmission including a common control channel using these 10-bit spare bits.

First, common search space allocation information may be transmitted and received through the bitmap method.

One bit may indicate a resource block group index (RBG Index) for a resource block group composed of P (P is a natural number) resource blocks.

At this time, the size of the resource block according to the system bandwidth may be as shown in Table 2.

TABLE 2

In Table 2

Means the number of downlink resource blocks available in the system. In this case, the downlink resource block may be a downlink physical resource block (PRB) or a downlink virtual resource block (VRB).

7 is an example of a resource block and a resource block group.

Referring to FIG. 7, system bandwidth

Is 30 (4.5 MHz), and in this case, three resource blocks form one resource block group according to Table 2.

If the base station allocates resource block group 1 to the common search space, the base station may transmit '0100000000' as a bitmap value to the terminal using 10 bits of the MIB.

However, when the common search space is allocated to the resource block groups according to Table 2 by a bitmap method, more than 10 bits may be required according to the system bandwidth. E.g,

Is 50, according to Table 2, the size of the RBG is 3, so a total of 17 bits must be used to allocate resources.

On the other hand, since the spare bits of the MIB are 10 bits in total, there may be a problem in resource allocation through the bitmap for the resource block group according to Table 2. Therefore, according to an embodiment of the present invention, a new RBG size according to system bandwidth is specified for allocating a bitmap resource using 10 bits. Equation 1 shows a method of obtaining the size of the RBG according to the system bandwidth. Of course, bitmap resource allocation using M bits (M is a natural number less than 10) is possible. In this case, the size of RBG replaces 10 with M in Equation (1).

[Equation 1]

(Equation 1

Is the nearest integer greater than or equal to X)

Table 3 shows the RBG size according to Equation 1 below.

TABLE 3

Using the resource block grouping method according to Table 3, a common search space can be allocated by a bitmap method using 10 bits or less for all system bandwidths.

E.g,

Is 50, one resource block group is formed by five resource blocks, and thus, ten resource block groups are formed as a whole, and the index of the resource block group that the base station intends to allocate to the common search space is 10-bit bitmap method. Will be allocated.

8 is an example of a resource block group according to Equation (1).

Referring to FIG. 8, the system bandwidth

Is 50, and one resource block group is formed by five resource blocks, and a total of 10 resource block groups are formed. In the example of FIG. 8, resource blocks having consecutive indexes form one resource block group.

Resource allocation in the common search space EPDCCH set (the common search space can also be seen as one EPDCCH set in the sense that the EPDCCH is searched in the common search space) may allow one bit to indicate an RBG index using a bitmap. .

In FIG. 8, if a common search space is to be allocated to resource blocks corresponding to RBG 5, it may be represented as '0000100000' as a bitmap and transmitted to the terminal using the spare bits of the MIB. Several resource block groups may be allocated together. For example, in FIG. 8, if a common search space is to be allocated to resource blocks corresponding to RBG 0 and RBG 5, the bitmap may be represented as '1000100000'. It can be transmitted to the terminal.

here,

Is a bitmap index if the number of RBs in the system band is not divided by 10, such as 6, 15, 25, 75

(In bitmap

The second bit. For example, for the bitmap 1000100000, the bitmap indices for the first and fifth bits, each of which has a bit value of 1, are

ego,

Im),

For

Indicates the number of RBs by the size of the RBG,

Is

RB can be indicated as much as. Where P is the size of RBG,

Is the nearest integer less than or equal to X.

And,

The corresponding bitmap index

The values of are filled with zeros. For example, system bandwidth

In the case of 6, since only 6 bits need to be used, the lower 4 bits may always be filled with zeros.

The common search space is a section to be searched in common to all terminals in the cell. Therefore, rather than allocating an optimized resource region to a specific terminal, it is possible to utilize a space that can be detected by all terminals in a cell. In consideration of the independent channel environment of each terminal in the cell, the resource allocation region may be evenly distributed in the frequency domain to utilize frequency diversity characteristics.

Provided is a method for configuring a resource block group as a combination of RBs evenly distributed in the frequency domain.

9 is another example of a resource block group according to Equation (1).

9, RB 7, RB 17, RB 27, RB 37 and RB 47 constitute one RBG 8. In addition, RB 8, RB 18, RB 28, RB 38, and RB 48 constitute one RBG 9, and RB 9, RB 19, RB 29, RB 39, and RB 49 constitute one RBG 10.

Resource block grouping as shown in FIG. 9 is the same method as the method of configuring a resource block group having the same resource block divided by 10 for the RB index.

For example, when expressed as a bitmap, '0010000000' indicates that RB 2, RB 12, RB 22, RB 32, and RB 42 are allocated to a common search space in the system band as shown in FIG. 9.

here,

about,

For

Indicates the number of RBs by the size of the RBG,

Is

RB can be indicated as much as. Where P is the size of RBG,

Means an integer less than or equal to X.

And,

The corresponding bitmap index

The values of are filled with zeros. For example, system bandwidth

In case of 6, only 6 bits need to be used, so the lower 4 bits can always be filled with 0.

According to another embodiment of the present invention, a common search space allocation method is provided.

Rel-11 decides to use a combination index r as a method for indicating resources of the EPDCCH. The contents are as follows.

N represents the size of the common search space, and N (= 2, 4, 8) PRB (Physical Resource Block) pairs constitute each EPDCCH set. And two bits are used to indicate the N value.

PRB index

The combination index r is used to indicate

).

The combination index r is defined as in Equation 2 below.

[Equation 2]

here,

ego

Is the same as the number of combinations for selecting y from x.

When r is calculated as in Equation 2, r is

It will have the same value as

To represent this r

Bit is required.

Similar methods can be used to allocate common search space.

In this method, the allocation unit of the common search space is a resource block group unit. Resource block groups may be grouped in the manner described with reference to Table 2, or may be grouped in the manner described with reference to

Equations

1 and 3 below.

Here, exemplary embodiments grouped by the method described with reference to Table 2 will be described.

Groups of resource block groups grouped in the system band are given an index.

Suppose that a common search space consists of eight RBs. Since the common search space is a space that all terminals should search in common, the number of RBs may be set to a constant value (N).

A combination index is used to indicate the resource block group allocated to the common search space.

Combination index indicating common search space

Follows the formula:

[Equation 3]

To direct

about(

Is the number of RBGs constituting the common search space, for example, when the size of the common search space is 8RB and the RBG is configured with 4RB,

Becomes 2),

(

Is the number of RBGs)

For example, if the RBG size is 4RB and the system band is 100RB,

Becomes 25,

Becomes 2. Here, in the case of allocating an RBG corresponding to the index of {1, 2} as a common search space

The value is calculated as follows.

When the base station intends to allocate RBGs having an index of {1, 2} as a common search space, the base station may include a value '0100101011' representing 299 as 10 bits in 10 bits of the MIB and transmit it through the PBCH. The UE may also receive this value and confirm that the common search space is allocated to the RBG having the indexes of the RBG {1, 2} according to Equation 3 below.

Combination index like this

In case of using, the required bit L is as follows.

[Equation 4]

(N is the size of the common search space, P is the number of resource blocks constituting the resource block group)

The necessary bits when resource block grouping is performed by the method of Table 2 are summarized as follows.

Table 4

In the case of the system bandwidth of 50RB, N = 9 was calculated.

here,

= 15, 25, 50, 75RB

If is not divided by P , then for RBG index RBG _i ,

silver

Has the size of,

Is

It has the size of mod P.

therefore,

If is

The size of resource allocation becomes smaller than

Also,

When = 50, since one RBG is composed of 3RBs, the size of a common search space may be configured of 9RBs.

Even when such a combination index is used, resource block groups may be distributed at equal intervals in frequency.

Referring to FIG. 10, the EPDCCH transmission method 1000 of the base station may include transmitting a PBCH (S1010), transmitting an EPDCCH (S1020), and the like.

The base station may use the EPDCCH to transmit control information common to the terminals in the cell. The base station may allocate a common search space as a search space where the EPDCCH can be found.

According to an embodiment of the present invention, the common search space for EPDCCH may be indicated in units of resource block groups. Since the number of resource blocks included in the system band can go up to 110, a lot of radio resources are required to indicate a common search space in units of resource blocks, which may be an overhead in communication between the base station and the terminal.

The resource block group may have a different size according to the system bandwidth. For example, when the system bandwidth is 25RB, the size of the resource block group may be 2RB, and when the system bandwidth is 100RB, the size of the resource block group may be 4RB. One example of the size of the resource block group according to this system bandwidth is shown in Table 2.

The size of the resource block group is shown in Equation 1

(Equation 1

May be determined as the nearest integer greater than or equal to X). In other words, the resource block group is composed of N (N is the nearest integer greater than or equal to the value of the system bandwidth in units of resource blocks divided by 10). If the M bit (M is a natural number less than or equal to 10) indicates resource allocation, the size of the RBG is

This can be

Table 3 describes the size of the resource block group for each system bandwidth for determining the size of the resource block group in this manner.

The resource block group may be composed of resource blocks having consecutive indexes. An example of the resource block group described with reference to FIG. 8 corresponds to this.

On the other hand, the resource block group may be composed of a combination of RBs evenly distributed in the frequency domain. For example, a resource block group may be formed of resource blocks having the same division of N (N is a natural number of 10 or less) for the RB index. If N is 10, 10 resource block groups are formed. As an example of a resource block group, referring to FIG. 9, RB 7, RB 17, RB 27, RB 37, and RB 47 constitute one RBG 8.

The base station allocates a common search space for EPDCCH reception in units of such resource block groups, and transmits information indicating the common search space to the terminal through the PBCH.

The PBCH may include MIB information. The MIB information includes 10-bit spare bits that are not used for other purposes, and the base station may transmit the above-described common search space indication information on the 10-bit spare bits.

The information indicating the common search space may be bitmap or combination index information. The base station allows each bit of the bitmap to indicate the index of the RBG, and can indicate indication information for the common search space through the value of each bit.

In addition, the base station is a combination index defined as in Equation 3r _RBG May indicate indication information about a common search space.

Such bitmap information or combination index information may be transmitted through the PBCH, and may be transmitted to the terminal through 10-bit spare bits included in the MIB information.

The base station transmits the indication information on the common search space to the terminal through the PBCH, and then transmits the EPDCCH to the terminal through some or all of the common search space. Since the UE knows the location of the common search space through the information received through the PBCH, it can find the EPDCCH by searching for the common search space and obtain control information from the EPDCCH.

Since the EPDCCH provides information on a data channel such as a PDSCH in which an SIB is provided, the UE may acquire SIB information while continuously receiving a data channel such as a PDSCH.

After acquiring such MIB and SIB information, the terminal may establish a connection with the base station and exchange other information.

Referring to FIG. 11, an EPDCCH receiving method 1100 of a UE may include receiving a PBCH (S1110), receiving an EPDCCH (S1120), and the like.

The terminal may receive MIB information from the base station through the PBCH and may receive SIB information through the data channel. In order to receive the data channel, the control channel including the control information for the data channel must be received, and in the NCT without the PDCCH, the control information can be received through the EPDCCH.

In order to receive the EPDCCH, it is necessary to receive information about a search space where the EPDCCH can be searched again. The base station may allocate a common search space for the EPDCCH in order to provide control information to all terminals to establish a connection with the base station.

According to an embodiment of the present invention, the terminal receives a PBCH including bitmap or combination index information indicating a common search space for the EPDCCH in units of resource block groups (S1110).

The size of the resource block group is shown in Equation 1

(Equation 1

This can be

In addition, the base station is a combination index defined as in Equation 3r _RBG May indicate indication information about a common search space. The terminal can identify the common search space location through this combination index.

After receiving the indication information on the common search space through the PBCH, the terminal receives the EPDCCH through blind decoding or search for the common search space.

The EPDCCH includes control information for the data channel, so that the UE may further receive the data channel, and may acquire SIB information through the data channel.

Referring to FIG. 12, the base station 120 may include a transmitter 122, a receiver 123, a controller 121, and the like.

The transmitter 122 may perform a function of transmitting a PBCH and an EPDCCH to a terminal according to an embodiment of the present invention, and the receiver 123 may perform a function of receiving information from a terminal according to an embodiment of the present invention. have. In addition, the controller 121 may control the transmitter 122 and the receiver 123 according to an exemplary embodiment of the present invention, and may perform a series of control operations for implementing the exemplary embodiment of the present invention.

The base station 120 and the terminal may transmit and receive control information through the EPDCCH, which is a control channel through the data region. In addition, the base station 120 and the terminal may communicate through a new type of carrier (NCT).

The controller 121 generates bitmap or combination index information indicating a common search space for an EPDCCH in units of a resource block group.

The transmitter 122 transmits a PBCH (Physical Broadcast Channel) including bitmap or combination index information to the terminal and transmits the EPDCCH to the terminal through a common search space.

Here, the resource block group may be composed of P (P is the nearest integer greater than or equal to the value of the system bandwidth in units of resource blocks divided by 10), the index of the resource block M (M is less than 10) Dividing by a natural number) may consist of the same resource blocks. The bitmap or combination index information may consist of 10 bits.

Referring to FIG. 13, the terminal 110 may include a receiver 111, a transmitter 112, a controller 113, and the like.

The receiver 111 may perform a function of receiving a PBCH and an EPDCCH from a base station according to an embodiment of the present invention, and the transmitter 112 may perform a function of transmitting information to a base station according to an embodiment of the present invention. have. In addition, the controller 113 may control the receiver 111 and the transmitter 112 according to an embodiment of the present invention and perform a series of control operations for implementing the embodiment of the present invention.

The receiver 111 may further include a PBCH receiver 118 and an EPDCCH receiver 119 as a lower block.

The base station and the terminal 110 may transmit and receive control information through the EPDCCH, which is a control channel through the data region. In addition, the base station and the terminal 110 may communicate through a new type of carrier (NCT).

The PBCH receiving unit 118 receives a physical broadcast channel (PBCH) including bitmap or combination index information indicating a common search space for an EPDCCH in units of a resource block group, and The EPDCCH receiver 119 searches the common search space and receives the EPDCCH from the base station.

In the above description, all elements constituting the embodiments of the present invention are described as being combined or operating in combination, but the present invention is not necessarily limited to the embodiments. In other words, within the scope of the present invention, all of the components may be selectively operated in combination with one or more. In addition, although all of the components may be implemented in one independent hardware, each or all of the components may be selectively combined to perform some or all functions combined in one or a plurality of hardware. It may be implemented as a computer program having a. Codes and code segments constituting the computer program may be easily inferred by those skilled in the art. Such a computer program may be stored in a computer readable storage medium and read and executed by a computer, thereby implementing embodiments of the present invention. The storage medium of the computer program may include a magnetic recording medium, an optical recording medium, and the like.

In addition, the terms "comprise", "comprise" or "having" described above mean that the corresponding component may be included, unless otherwise stated, and thus excludes other components. It should be construed that it may further include other components instead. All terms, including technical and scientific terms, have the same meanings as commonly understood by one of ordinary skill in the art unless otherwise defined. Terms commonly used, such as terms defined in a dictionary, should be interpreted to coincide with the contextual meaning of the related art, and shall not be construed in an ideal or excessively formal sense unless explicitly defined in the present invention.

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 idea 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 APPLICATION

This patent application claims priority under No. 119 (a) (35 USC § 119 (a)) of the US Patent Act No. 10-2012-0149219, filed with Korea on 20 December 2012. All content is incorporated by reference in this patent 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 base station to transmit the Enhanced Physical Downlink Control Channel (EPDCCH),

Transmitting a physical broadcast channel (PBCH) including a bitmap or combination index information indicating a common search space for the EPDCCH in units of a resource block group; and

Transmitting the EPDCCH to the terminal through the common search space.
The method of claim 1,

The resource block group is composed of N (N is the nearest integer greater than or equal to the value of the system bandwidth in units of resource blocks divided by 10) EPDCCH transmission method, characterized in that.
The method of claim 1,

The resource block group is an EPDCCH transmission method, characterized in that the remainder divided by the index of the resource block by N (N is a natural number of 10 or less).
The method of claim 1,

The bitmap or combination index information is composed of 10 bits.
The method of claim 1,

In the combination index information, the combination index ( r RBG ) is

( RBG i is the index of the resource block group allocated to the common search space, N RBG is the number of resource block groups constituting the common search space,
Is the number of resource block groups in the system band,
,
)

EPDCCH transmission method characterized in that.
In the method for the terminal to receive the Enhanced Physical Downlink Control Channel (EPDCCH),

Receiving a physical broadcast channel (PBCH) including a bitmap or combination index information indicating a common search space for the EPDCCH in units of a resource block group; and

Searching for the common search space and receiving the EPDCCH from the base station.
The method of claim 6,

The resource block group is composed of N (N is the nearest integer greater than or equal to the value of the system bandwidth in units of resource blocks divided by 10) EPDCCH receiving method, characterized in that.
The method of claim 6,

The resource block group is an EPDCCH receiving method, characterized in that the remainder obtained by dividing the index of the resource block by N (N is a natural number of 10 or less).
The method of claim 6,

In the combination index information, the combination index ( r RBG ) is

( RBG i is the index of the resource block group allocated to the common search space, N RBG is the number of resource block groups constituting the common search space,
Is the number of resource block groups in the system band,
,
)

EPDCCH receiving method characterized in that.
In the base station for transmitting the EPDCCH (Enhanced Physical Downlink Control Channel),

A controller configured to generate bitmap or combination index information indicating a common search space for the EPDCCH in units of a resource block group; And

And a transmitter for transmitting a physical broadcast channel (PBCH) including the bitmap or combination index information to a terminal and transmitting the EPDCCH to the terminal through the common search space.
The method of claim 10,

The resource block group is a base station, characterized in that N (N is the nearest integer greater than or equal to the value of the system bandwidth in units of resource blocks divided by 10).
The method of claim 10,

The resource block group is a base station, characterized in that the remainder by dividing the index of the resource block by N (N is a natural number less than 10) is composed of the same resource blocks.
The method of claim 10,

And the bitmap or combination index information consists of 10 bits.
The method of claim 10,

In the combination index information, the combination index ( r RBG ) is

( RBG i is the index of the resource block group allocated to the common search space, N RBG is the number of resource block groups constituting the common search space,
Is the number of resource block groups in the system band,
,
)

And a base station.
In the terminal for receiving an Enhanced Physical Downlink Control Channel (EPDCCH),

A PBCH receiving unit for receiving a physical broadcast channel (PBCH) including a bitmap or combination index information indicating a common search space for the EPDCCH in units of a resource block group; and

And an EPDCCH receiver for searching the common search space and receiving the EPDCCH from the base station.
The method of claim 15,

The resource block group is a terminal, characterized in that N (N is the nearest integer greater than or equal to the value of the system bandwidth in units of resource blocks divided by 10) the number of resource blocks.
The method of claim 15,

The resource block group is a terminal, characterized in that the remainder divided by N (N is a natural number less than 10) of the resource block is composed of the same resource blocks.
The method of claim 15,

In the combination index information, the combination index ( r RBG ) is

( RBG i is the index of the resource block group allocated to the common search space, N RBG is the number of resource block groups constituting the common search space,
Is the number of resource block groups in the system band,
,
)

Terminal characterized in that the.