JP6515491B2 - RADIO TERMINAL, RADIO STATION, AND METHODS THEREOF - Google Patents

Description

  The present application relates to wireless communication systems, and more particularly to detection of cell identifier conflicts.

  The following describes the radio frame structure used in the 3rd Generation Partnership Project (3GPP) Release 8 (called Long Term Evolution (LTE)) and later, and then the 3GPP Release 10 (LTE-Advanced and LTE-Advanced and LTE-Advanced). The carrier aggregation (CA) introduced in (4) will be described. In addition, Licensed Assisted Access (LAA) currently being discussed for 3GPP Release 13 and associated Licensed Shared Access (LSA) will be described.

  First, the radio frame structure of LTE will be described. In 3GPP Release 8 and later, two types of radio frame structures are provided. One is called frame structure type 1 and can be applied to frequency division duplex (FDD). The other is called frame structure type 2 and is applicable to Time division duplex (TDD). As shown in FIG. 11, in any type 1 and type 2 frame structure, the length of one radio frame is 10 milliseconds, and one radio frame is from 10 subframes. It is configured. In the case of TDD, five subframes (# 0 to # 4) in the first half and five subframes (# 5 to # 9) in the second half are respectively referred to as half frames. The half frame length is 5 milliseconds. The length of one subframe is one millisecond. Furthermore, one subframe is decomposed into two slots of 0.5 ms each. In the case of a normal cyclic prefix, one slot consists of 7 symbols in the time domain (single carrier frequency division multiple access (SC-FDMA) symbols in the uplink case, orthogonal frequency division multiplexing (OFDM) symbols in the downlink case )including. Thus, one subframe contains 14 symbols in the time domain.

  Furthermore, in 3GPP Release 10, the specification of Carrier Aggregation (CA) function is performed, in which a radio base station (eNode B: eNB) and a radio terminal (User Equipment: UE) communicate using multiple cells. It was In addition, the cell which UE can use by CA is limited to the several cell of one eNB (namely, several cell operated or managed by eNB). The cell used by the UE in the CA is a Primary cell (PCell) already used as a serving cell at the time of starting the CA and a secondary cell (Secondary cell: SCell) used additionally or subordinately are categorized. In PCell, at the time of (re) establishment of a radio connection (Radio Resource Control (RRC) Connection Establishment, RRC Connection Re-establishment), Non Access Stratum (NAS) mobility information (NAS mobility information) and security information (security input) Are transmitted and received (see Section 7.5 of Non-Patent Document 1).

  The introduction of CA has made it possible to realize functionally high-speed communication, but in actual operation, due to the limited frequency (shortage) assigned to each operator, there is concern about the future increase in mobile traffic The current situation is that Therefore, in 3GPP standardization, the discussion of Unlicensed LTE (also referred to as LTE-U or U-LTE; hereinafter referred to as LTE-U) that executes LTE using an Unlicensed Frequency Band (Unlicensed Spectrum) is It has been started (non-patent documents 2, 3).

  As an implementation method of LTE-U, Licensed Assisted Access (LAA) in which the eNB communicates with the UE on the non-licensed frequency in conjunction with the license frequency (for example, as a SCell of CA) and the UE communicates on the non-licensed frequency only There are two possible ways of doing standalone (SA). Here, for example, a 5 GHz band is assumed as a non-licensed frequency, and the 5 GHz band is a frequency used also for a radar system and a wireless LAN (WLAN, also referred to as WiFi). Therefore, the SA method that communicates only with non-licensed frequency is concerned with the feasibility of the fine control specified in LTE, and the LAA method (also called LA-LTE) with relatively high feasibility is considered It is considered central. The following description focuses on LTE-U based on the LAA scheme that performs CA on licensed and non-licensed frequencies. The license frequency refers to a dedicated frequency assigned to a specific operator. Also, the non-line sense frequency refers to a frequency not assigned to a specific operator or a shared frequency assigned to a plurality of operators. In the latter case, the frequency may be referred to as a license shared frequency instead of a non-licensed frequency, and communication using the frequency may also be referred to as a Licensed Shared Access (LSA). Hereinafter, these frequencies other than the license frequency licensed only to a specific operator will be collectively referred to as a non-licensed frequency.

  The LTE-U based on the LAA scheme is basically executed according to the sequence shown in FIG. Here, it is assumed that the eNB performs data transmission (or reception) with UE # 1 in Cell # 1 of the licensed frequency and Cell # 2 of the non-licensed frequency. First, a radio connection is established between eNB and UE # 1 in Cell # 1 (RRC Connection Establishment, 1201), and a bearer is further established between the core network (Evolved Packet Core: EPC) and UE # 1 (RRC Connection Establishment, 1201) Not shown). That is, Cell # 1 is the PCell of UE # 1. eNB has downlink (DL) user data (also referred to as User Plane (UP) data) to be transmitted to UE # 1 or uplink (UL) user data that UE # 1 wants to transmit , Transmit and receive the user data in Cell # 1 (DL (or UL) UP data transmission, 1202).

  Next, when the eNB determines that UE # 1 is enabled to transmit and receive user data in Cell # 2 at a certain time (Trigger LTE-U for UE # 1, 1203), Cell # 1 in Cell # 1 Control information on the radio resource configuration of No. 2 is sent to UE # 1 (Radio Resource Configuration for Cell # 2, 1204). The said control information is corresponded to RadioResourceConfigDedicated Information Element (IE) and RadioResourceConfigCommon IE transmitted by RRC Connection Reconfiguration message in LTE (nonpatent literature 4). At this time, Cell # 2 becomes SCell of UE # 1. When transmitting user data in downlink, the eNB performs sensing in Cell # 2 and determines whether the Cell # 2 is usable (Perform channel sensing, 1205). If the eNB determines that Cell # 2 is available, it transmits / receives user data to / from UE # 1 (DL (or UL) UP data transmission, 1206). Thus, further improvement in throughput or increase in cell capacity can be expected by using the non-licensed frequency.

  In addition, the above-mentioned sensing is also called Listen Before Talk (LBT) (non-patent document 2), and communication by LTE-U or other radio systems (eg WLAN) by other operators is performed at the target non-licensed frequency. It determines whether or not it is being performed in the vicinity, and corresponds to Channel Availability Check (CAC) for the radar system, and Clear Channel Assessment (CCA) performed in Access Point (AP) in WLAN (Patent Document 1) ).

3GPP TS 36.300 V12.2.0 (2014-06), “3rd Generation Partnership Project; Technical Specification Group Radio Access Network; Evolved Universal Terrestrial Radio Access (E-UTRA) and Evolved Universal Terrestrial Radio Access Network (E-UTRAN); Overall description Stage 2 (Release 12) ”, June 2014 3GPP RP-131635, “Introducing LTE in Unlicensed Spectrum”, Qualcomm, Ericsson, December 2013 3GPP workshop on LTE in unlicensed spectrum, RWS-140002, “LTE in Unlicensed Spectrum: European Regulation and Co-existence Considerations”, Nokia, June 2014 3GPP TS 36.331 V12.2.0 (2014-06), "3rd Generation Partnership Project; Technical Specification Group Radio Access Network; Evolved Universal Terrestrial Radio Access (E-UTRA); Radio Resource Control (RRC); Protocol specification (Release 12)" , June 2014 3GPP TR 36.842 V12.0.0 (2013-12), “3rd Generation Partnership Project; Technical Specification Group Radio Access Network; Study on Small Cell Enhancements for E-UTRA and E-UTRAN; Higher layer aspects (Release 12)”, 2013 December

  In LAA, Primary Synchronization Signal (PSS) and Secondary Synchronization Signal (SSS) need to be transmitted even in cells of unlicensed frequency. The UE can synchronize to the cell of the non-licensed frequency by detecting the PSS and SSS transmitted on the cell of the non-licensed frequency (ie can detect the position of the 10 ms radio frame boundary), Physical Cell Identity (PCI) of a cell of license frequency can be detected.

  However, in LAA, PCI conflicts may occur due to cells of two unlicensed frequencies operated by different operators using the same PCI. PCI conflicts include PCI collision and PCI confusion. PCI collision means that two cells in close proximity (for example, adjacent to each other) use the same PCI, and PCI confusion is that there are two cells with the same PCI in the periphery of a certain cell (for example, each of the cells) It means that it has an adjacent cell).

  For example, as shown in FIG. 13, the UE 93 has another operator (Operator B) having the same PCI (PCI # 5) as the cell (Cell # 2) provided by the eNB 91 of the operator (Operator A) to which the UE 93 belongs. False detection of the cell (Cell # 3), terminal measurement (ie, measurement of Reference Signal Received Power (RSRP) and Reference Signal Received Quality (RSRQ)) for Cell # 3 of operator B, and Cell # The measurement result of No. 3 may be erroneously reported to the eNB 91 in the serving cell (cell # 1) as a terminal measurement result on Cell # 2. And eNB91 may set Cell # 2 to the said UE93, in order to start CA based on the said terminal measurement result. Then, the UE 93 may not be able to obtain sufficient communication quality in Cell # 2.

  In addition, even if a PCI conflict (conflict) occurs among a plurality of cells, the UE detects these cells by detecting an Evolved Universal Terrestrial Radio Access Network (E-UTRAN) Cell Global ID (ECGI). It may be distinguishable (distinguish, differentiate or discriminate). The ECGI is an identifier for uniquely identifying an E-UTRAN cell globally. However, in a cell of an unlicensed frequency used as a secondary cell of carrier aggregation in LAA, System Information Block type 1 (SIB1) including ECGI may not be transmitted. Therefore, if a cell of a non-licensed frequency (or a shared license frequency) is used as a secondary cell (SCell) of carrier aggregation in LAA (or LSA), the UE should distinguish that cell from other cells based on ECGI. May be difficult.

  It should be noted that PCI conflicts are not only in situations where multiple LTE operators as described above use non-licensed frequencies (or licensed shared frequencies) for LAA (or LSA), but also in various situations It can occur. PCI conflicts, or PCI collisions or PCI confusions, can occur when any of unlicensed frequency, licensed shared frequency, and licensed frequency are used, and between multiple operators and within one operator Can occur either. Furthermore, PCI confusion can also occur when multiple cells use different frequencies, but they use the same PCI. Furthermore, PCI is an example of a cell identifier (physical identifier). In wireless communication systems other than LTE, although other cell identifiers different from PCI are used (for example, the Primary Scrambling Code (PSC) used in 3GPP Universal Mobile Telecommunications System (UMTS)), PCI conflicts Similarly, conflicts with these other cell identifiers may also occur.

  Accordingly, one of the goals that the embodiments disclosed herein seek to achieve is to provide an apparatus, method, and program for assisting in detection of cell identifier conflicts by a network. .

  In a first aspect, a method performed by a wireless terminal comprises: (a) communicating with a wireless station in a serving cell using a first frequency; (b) detecting at least one cell using a second frequency And (c) transmitting, to the wireless station in the serving cell, timing information regarding frame timing of the at least one detected cell or detection timing of the cell and a cell identifier of the detected at least one cell. including.

  In a second aspect, a method performed by a wireless station comprises: (a) communicating with a wireless terminal in a serving cell of the wireless terminal using a first frequency; and (b) a second frequency by the wireless terminal Receiving, from the wireless terminal at the serving cell, timing information related to frame timing of at least one cell detected at a cell or detection timing of the cell and a cell identifier of the detected at least one cell.

  In a third aspect, a wireless terminal includes at least one processor. The at least one processor communicates with a wireless station in a serving cell using a first frequency, detects at least one cell using a second frequency, and detects frame timing or cells of the detected at least one cell. Timing information related to the detection timing of and the cell identifier of the detected at least one cell are configured to be transmitted to the wireless station in the serving cell.

  In a fourth aspect, a wireless station includes at least one processor. The at least one processor communicates with a wireless terminal in a serving cell of the wireless terminal using a first frequency, and detection of frame timing or cells of at least one cell detected at a second frequency by the wireless terminal Timing information related to timing and a cell identifier of the detected at least one cell are configured to be received from the wireless terminal at the serving cell.

  In a fifth aspect, a program includes instructions (software code) for causing a computer to perform the method according to the above-mentioned first aspect when read by a computer.

  In a sixth aspect, a program includes instructions (software code) for causing a computer to perform the method according to the above-mentioned second aspect when read by a computer.

  According to the above aspects, it is possible to provide an apparatus, method, and program for assisting in detection of cell identifier conflict by a network.

BRIEF DESCRIPTION OF DRAWINGS FIG. 1 is a diagram illustrating an example of a configuration of a wireless communication system according to some embodiments. BRIEF DESCRIPTION OF DRAWINGS FIG. 1 is a diagram illustrating an example of a configuration of a wireless communication system according to some embodiments. BRIEF DESCRIPTION OF DRAWINGS FIG. 1 is a diagram illustrating an example of a configuration of a wireless communication system according to some embodiments. It is a flowchart which shows an example of operation | movement of the radio | wireless terminal which concerns on 1st Embodiment. FIG. 7 is a timing diagram illustrating an example of frame timing relationships between a serving cell and other cells. It is a flowchart which shows an example of operation | movement of the wireless base station which concerns on 1st Embodiment. It is a flowchart which shows an example of operation | movement of the radio | wireless terminal which concerns on 1st Embodiment. BRIEF DESCRIPTION OF DRAWINGS FIG. 1 is a diagram illustrating an example of a configuration of a wireless communication system according to some embodiments. BRIEF DESCRIPTION OF DRAWINGS FIG. 1 is a diagram illustrating an example of a configuration of a wireless communication system according to some embodiments. It is a block diagram which shows the structural example of the radio | wireless terminal which concerns on some embodiment. It is a block diagram which shows the structural example of the wireless base station which concerns on some embodiment. It is a figure which shows the radio frame structure and sub-frame structure of LTE. It is a sequence diagram which shows an example of operation | movement of the wireless base station and radio | wireless terminal in LTE-U. It is a figure for demonstrating an example of operation | movement of UE in the condition where several cells use PCI.

  Hereinafter, specific embodiments will be described in detail with reference to the drawings. In the drawings, the same or corresponding elements are denoted by the same reference numerals, and for the sake of clarity of the description, redundant description will be omitted as necessary.

  The embodiments shown below are described mainly for Evolved Packet System (EPS) accommodating LTE and System Architecture Evolution (SAE). However, these embodiments are not limited to EPS, and other mobile communication networks or systems, such as 3GPP UMTS, 3GPP2 CDMA2000 system (1xRTT, High Rate Packet Data (HRPD), global system for mobile communications (1xRTT). The present invention may be applied to GSM) / General packet radio service (GPRS) system, WiMAX system, etc.

First Embodiment
First, some examples of Unlicensed LTE that use Unlicensed frequency bands (Unlicensed spectrum) targeted by a plurality of embodiments including this embodiment will be described. Here, Unlicensed LTE is also referred to as LTE-U or U-LTE, and will be described as LTE-U hereinafter. In addition, the non-licensed frequency is, for example, a frequency used also for a radar system and a wireless LAN (WLAN, also called WiFi), and a frequency other than the license frequency assigned only to a specific operator (that is, a service provider). Point to. For example, a 5 GHz band is assumed as a non-licensed frequency, but it is not limited to this. Furthermore, it goes without saying that the embodiments described below are also applicable to a shared frequency (Shared frequency band, Shared spectrum) commonly assigned to a plurality of operators. Hereinafter, these frequencies other than the license frequency are generically referred to as non-license frequency.

  FIGS. 1A and 1B are diagrams showing configuration examples of LTE-U wireless communication systems and other systems targeted by a plurality of embodiments including this embodiment. In the example of FIG. 1A, the wireless communication system includes an LTE wireless base station (eNB) 11 and a wireless terminal (UE) 3. The eNB 11 and the UE 3 are configured to perform normal LTE communication at the license frequency (F1), and configured to perform LTE-U communication at the non-license frequency (F2). In the example of FIG. 1B, in addition to the example of FIG. 1A, the LTE eNB 11 manages the remote base station 12 (RRH or RRE), and the remote base station 12 communicates by LTE-U at the non-licensed frequency (F2) .

  The configurations of FIGS. 1A and 1B may co-exist in the same system. Furthermore, FIG. 1A and FIG. 1B show only a part of the wireless communication system assumed, and in fact, a plurality of eNBs and RRHs / RREs and a plurality of UEs exist around eNB11, RRH / RRE12, and UE3. , Cells of a plurality of license frequencies are managed by the plurality of eNBs and the RRH / RRE. Furthermore, a plurality of wireless LAN access points (WLAN APs) and a plurality of wireless LAN terminals (WLAN terminals) may be present around eNB11, RRH / RRE 12, and UE3. In the following description, eNBs having an LTE-U function are collectively referred to as a radio base station 1 or an LTE-U eNB1. That is, the radio base station 1 or the LTE-U eNB 1 corresponds to the eNB 11 in the configuration of FIG. 1A, and corresponds to the eNB 11 and the RRH / RRE 12 in the configuration of FIG. 1B. For convenience of explanation, the node corresponding to only the RRH / RRE 12 in the configuration of FIG. 1B may be referred to as the radio base station 1 or the LTE-U eNB 1.

  In the above and the following description, it is assumed that LTE-U is implemented in LAA (also called LA-LTE). As described above, in the LAA, the radio base station (LTE-U eNB) 1 and the radio terminal (UE) 3 carry-aggregate (CA) the cell of the license frequency and the cell of the non-license frequency, and the cell of the license frequency Is used as a primary cell (PCell), and a cell of a non-licensed frequency is used as a secondary cell (SCell). As already mentioned, LTE-U may be performed on a shared frequency (Shared frequency band) assigned to a plurality of operators (service providers) instead of being performed on non-licensed frequencies. In this case, LTE-U may be implemented by the above-described LAA or a similar scheme. Alternatively, LTE-U eNB1 and UE3 perform CA using a plurality of (for example, two of F3 and F4) shared frequencies and execute normal LTE with one shared frequency (F3) as a PCell. The LTE-U may be performed with one shared frequency (F4) as the SCell. As already mentioned, LTE-U in shared frequency is also called Licensed Shared Access (LSA) in particular. Furthermore, LTE-U eNB1 and UE3 use a shared frequency (for example, F3) assigned to a plurality of operators and a narrow non-licensed frequency (for example, F2, for example, 5 GHz band) that is not assigned to any operator Then, CA may be performed, and the common LTE may be executed with the shared frequency (F3) as the PCell, and the LTE-U may be executed with the non-licensed frequency (F2) in the narrow sense as the SCell.

  FIG. 2 shows an example of a situation where multiple cells provided by different LTE operators use the same PCI. In the example of FIG. 2, the LTE-U eNB1 is managed by the operator A, operates Cell # 1 (PCell for UE3) at the license frequency F1, and operates Cell # 2 at the non-license frequency F2. Cell # 2 has PCI # 5. On the other hand, the LTE-U eNB2 is managed by another operator B different from the operator A, and operates Cell # 3 at the non-licensed frequency F2. In the example of FIG. 2, since Cell # 2 and Cell # 3 are adjacent to each other and have the same PCI # 5, PCI collision may occur in UE3. Although Cell # 2 and Cell # 3 having the same PCI # 5 are not adjacent to each other, they may be arranged to be adjacent to Cell # 1, and in this case, PCI confusion in LTE-U eNB1. May occur.

  The UE 3 shown in FIG. 2 operates to communicate with the LTE-U eNB1 in the serving cell (Cell # 1) of the license frequency (F1). The UE 3 further operates to detect at least one cell at the unlicensed frequency (F2). In the example of FIG. 2, UE3 can detect Cell # 2 or Cell # 3 or both at the unlicensed frequency (F2). UE 3 also operates to transmit at least one cell's timing information and cell identifier (eg, PCI) detected at the non-licensed frequency (F2) to LTE-U eNB 1 at serving cell (Cell # 1). Here, the timing information is information on frame timing of at least one cell detected at the non-licensed frequency (F2) or information on detection timing of the cell. The serving cell may be PCell, a cell similar to PCell (for example, PSCell of Dual Connectivity), a serving cell of a predetermined cell group, or all serving cells of the wireless terminal. Note that the term “frame timing” in this embodiment and other embodiments refers to the timing at which the wireless terminal (eg, UE3) receives the beginning (frame boundary) of a wireless frame or subframe, or a wireless base station (eg, eNB1) ) May mean the timing of transmitting the beginning (frame boundary) of the radio frame or subframe. Alternatively, the term frame timing may mean the timing at which a wireless terminal receives a synchronization signal (eg, PSS, SSS), or the timing at which a wireless base station transmits a synchronization signal (eg, PSS, SSS) . here,

  FIG. 3 is a flowchart illustrating an example (process 300) of the process performed by the UE 3. At block 301, UE3 attempts to detect a cell at unlicensed frequency (F2). In block 302, UE3 reports the PCI and timing information of the cell (E.G., Cell # 3) detected in block 301 to LTE-U eNB1 in the serving cell (Cell # 1) of the license frequency (F1).

  Hereinafter, some examples of timing information transmitted from UE3 to LTE-U eNB1 will be shown. In some implementations, the timing information may indicate information about frame timing of a detected cell at a non-licensed frequency (F2). For example, the timing information may indicate the relationship between the frame timing of the cell (eg, Cell # 2 or Cell # 3) detected at the non-licensed frequency (F2) and the frame timing of the serving cell (Cell # 1). . The frame timing relationship is, in one example, the frame timing difference between the radio frame of the non-licensed frequency cell (eg, Cell # 2 or Cell # 3) and the serving cell (eg, Cell # 1) received at UE3. (Frame timing difference) may be used. In this case, a plurality of cells (eg, Cell # 2 and Cell # 3) configured to use the same PCI (eg, PCI # 5) and the same frequency (eg, F2) communicate with the serving cell. It is distinguished by having mutually different frame timing differences.

  The frame timing difference may be defined as the difference between the start position of the radio frame of the cell of the non-licensed frequency received at UE 3 (ie, the radio frame boundary) and that of the serving cell. More specifically, the frame timing difference is the time difference (eg, N nanoseconds) between the start position of the radio frame of the non-licensed frequency cell received at UE 3 (ie, the radio frame boundary) and that of the serving cell. , M microseconds, or X subframes). Alternatively, the frame timing difference may be defined as the difference (eg, Y subframes) between the subframe number of the non-licensed frequency cell received at UE 3 at the same observation time and that of the serving cell. Alternatively, the frame timing difference may be defined as the time difference between the subframe in which the cell synchronization signal (eg, PS, SSS) of the non-licensed frequency received at UE 3 is transmitted and that of the serving cell.

If the frame structure (that is, duplex mode (FDD or TDD)) is different between the serving cell and the non-licensed frequency cell, the difference may be taken into consideration. That is, both the first synchronization signal (PSS) and the second synchronization signal (SSS) are transmitted in the first subframe (subframe # 1) and the sixth subframe (subframe # 6). Although it is the same regardless of the frame structure, the radio resources to which PSS and SSS are actually transmitted are slightly different between the frame structures. For example, in the case of frame structure type 1 (FDD), the first synchronization signal (PSS) is transmitted in the last OFDM symbol of slot # 0 and slot # 10 respectively, but in the case of frame structure type 2 (TDD) , The first synchronization signal (PSS) is transmitted in the third OFDM symbol of subframe # 1 and subframe # 6 respectively. On the other hand, in the case of frame structure type 1 (FDD), the second synchronization signal (SSS) is transmitted in slot # 0 and slot # 10, but in the case of frame structure type 2 (TDD), the second The synchronization signal (SSS) of is transmitted in slot # 1 and slot # 11. Therefore, when the timing information (e.g., the above-mentioned difference in frame timing) is derived with a precision (e.g., microseconds) finer than that of the sub-frame (1 ms), the difference between the frame structures may be taken into consideration.

  FIG. 4 shows an example of the frame timing relationship between the serving cell and other cells. In the example of FIG. 4, the start position of the radio frame of Cell # 2 received at UE3 is substantially aligned with that of the serving cell (Cell # 1). Thus, the frame timing difference between Cell # 2 and Cell # 1 can be substantially zero subframes, and can be several microseconds. On the other hand, the start position of the radio frame of Cell # 3 is not aligned with that of the serving cell (Cell # 1) and deviates from that of the serving cell (Cell # 1) by about 4 subframe times. In other words, the difference in subframe number between Cell # 3 and Cell # 1 received within a certain observation period (eg, 1 subframe period = 1 ms) is 6. Therefore, the frame timing difference between Cell # 3 and Cell # 1 can be said to be 4 subframes (or 6 subframes) and can also be said to be approximately 4 milliseconds. In addition, UE3 expresses the said frame timing difference with positive and negative in the early (advancing) and late (delaying) with reference to a serving cell (Cell # 1), and also those information to LTE-U eNB1. You may report it.

  In another example, in the frame timing relationship, the start position (radio frame boundary) of the radio frame of the cell (eg, Cell # 2 or Cell # 3) of the non-licensed frequency received at UE3 is the serving cell (eg, Cell #) It may indicate whether or not it is substantially aligned with that of 1). The fact that the start positions of the radio frames of the two cells are "substantially aligned" can be reworded as the radio frames of the two cells being substantially synchronized. The fact that the start positions of the radio frames of the two cells are “substantially aligned” means that the time difference between the start positions of the radio frames of these two cells received at the UE 3 is a predetermined threshold (eg, several tens of micro-numbers) It may be determined by being within one hundred microseconds. Alternatively, "substantially aligned" means that the subframe numbers of two cells received at UE3 within a certain observation period (eg, 1 subframe period = 1 ms) are identical. It may be determined by

  The frame timing relationship notified from the UE 3 to the LTE-U eNB 1 as timing information is in addition to the fact that the non-licensed frequency and the start position of the radio frame of the serving cell are substantially aligned (the radio frames are synchronized). It may indicate whether the System Frame Number (SFN) of these two cells is the same. The SFN is a number between 0 and 1023 sequentially assigned to the radio frame. The SFN can be obtained at UE 3 by decoding the Physical Broadcast Channel (PBCH) including the Master Information Block (MIB) in the upper 8 bits. Furthermore, the lower 4 bits can be obtained at UE 3 by receiving the MIB (that is, PBCH) that is repeatedly transmitted every 10 ms and recognizing the repetition timing. In this case, a plurality of cells (eg, Cell # 2 and Cell # 3) configured to use the same PCI (eg, PCI # 5) and the same frequency (eg, F2) have different SFNs. It is distinguished by.

  In some implementations, the timing information reported from UE3 to LTE-U eNB1 may indicate information regarding detection timing of non-licensed frequency cells detected at UE3. The information on the detection timing of the cell indicates, for example, the ON period of the cell detected by UE3, that is, the information on the time or period in which the cell detected in the non-licensed frequency (F2) is operated (or operated). May be That is, the timing information may indicate the time or period in which at least one cell detected at the non-licensed frequency (F2) is operated (or operated). When UE3 detects the cell of the same PCI multiple times, the timing information reported to UE1 from UE3 may include a list of multiple ON periods. The list of ON periods may be reported for each PCI. Alternatively, the ON period and PCI may be associated and reported in chronological order in the order of detection. In this example, where the timing information indicates the ON period of the cell, the operation of the cells (Cell # 2 and Cell # 3) of the non-licensed frequency is dynamically switched, that is, the ON / OFF of the cell is periodically or aperiodically. It is particularly effective in switching situations.

  In one example, the ON period included in the timing information may indicate a detection time or a detection period when a cell of a non-licensed frequency is detected at UE3. Specifically, the ON period may indicate an absolute time when a cell of a non-licensed frequency is detected. Alternatively, the ON period may indicate the radio frame number (SFN) or subframe number or both of the serving cell when a cell of the non-licensed frequency is detected. Alternatively, the ON period may relatively express the detection time or detection period of the cell of the non-licensed frequency based on a predetermined reference time (for example, the reporting time of timing information). The ON period may indicate, for example, the relative number of radio frames viewed from the reference time point (how many frames ago was detected), or the relative subframe number (how many subframes earlier detected).

  Subsequently, an example of the operation of the LTE-U eNB 1 or other control node will be described below. In some implementations, the LTE-U eNB 1 may use the PCI and timing information received from UE 3 to detect PCI conflicts, ie, PCI collisions or PCI confusions. In some implementations, this process may be performed on another control node (eg, Self-Organizing Network (SON) controller, Software-Defined Network (SDN) controller, Operations Support System (OSS), or different) than LTE-U eNB1. It may be performed by an Element Management System (EMS).

  FIG. 5 is a flowchart showing an example (500) of the process of the LTE-U eNB1. In block 501, the LTE-U eNB1 receives PCI and timing information on the cell (eg, Cell # 3) of the non-licensed frequency (F2) detected by the UE 3 from the UE 3 in the serving cell (Cell # 1). In block 502, the LTE-U eNB 1 detects a cell of the non-licensed frequency detected by the UE 3 (eg, Cell # 3) and a cell of the non-licensed frequency operated by the operator A based on the received PCI and timing information. eg, detects a PCI conflict between Cell # 2).

  In some implementations, if the timing information indicates information on the frame timing of the non-licensed frequency cell, the LTE-U eNB1 can manage the timing information and PCI received from the UE3 with the LTE-U eNB1 or an operator A that manages this. The frame timing and PCI of a cell (eg, Cell # 2) of a non-licensed frequency being operated in the vicinity of the serving cell (Cell # 1) may be compared. Then, the LTE-U eNB1 is the cell of the detected cell (eg, Cell # 3) of the cell (eg, Cell # 2) provided at the non-licensed frequency by the LTE-U eNB1 or the operator A that manages this. If it matches, but the frame timing of these two cells is not aligned, the detected cell (eg, Cell # 3) and the LTE-U eNB1 or the cell of operator A (eg, Cell # 2) It may detect that a PCI conflict has occurred.

  In some implementations, if the timing information indicates information on the frame timing of the non-licensed frequency cell, then LTE-U eNB1 first detects the non-licensed frequency detected by UE3 based on the timing information received from UE3. It may be determined whether the frame timing relationship between the cell (eg, Cell # 3) and the serving cell (Cell # 1) is appropriate. For example, LTE-U eNB1 determines whether the start position (radio frame boundary) of the radio frame of the cell (eg, Cell # 3) of the non-licensed frequency detected by UE3 and that of the serving cell (Cell # 1) are aligned You may judge. Instead of this, in the LTE-U eNB1, the start position of the radio frame of the non-licensed frequency cell (eg, Cell # 3) detected by the UE 3 is a predetermined offset with respect to that of the serving cell (eg, Cell # 1) It may be determined whether or not it is deviated or whether it is within a predetermined offset. Next, when the relationship between the cell timing of the non-licensed frequency detected by UE3 (eg, Cell # 3) and the frame timing of the serving cell (Cell # 1) is not appropriate, LTE-U eNB1 detects the cell detected by UE3 ( eg, Cell # 3) may be assumed to be a cell operated by another operator (eg, operator B)). Then, LTE-U eNB 1 is a cell (eg, Cell in which a non-licensed frequency cell (eg, Cell # 2) operated by operator A in the vicinity of the serving cell (Cell # 1) is estimated to be that of another operator (eg, When using the same PCI as Cell # 3), a PCI conflict may be detected.

  In some implementations, if the timing information indicates information on the ON period of the non-licensed frequency cell, the LTE-U eNB1 can manage the timing information and PCI received from the UE3 with the LTE-U eNB1 or an operator A that manages this. And the ON period and PCI of a cell (eg, Cell # 2) of a non-licensed frequency operated in the vicinity of the serving cell (Cell # 1). Then, the LTE-U eNB1 is the cell of the detected cell (eg, Cell # 3) of the cell (eg, Cell # 2) provided at the non-licensed frequency by the LTE-U eNB1 or the operator A that manages this. If it matches, but the ON periods of these two cells do not match (not aligned), the detected cell (eg, Cell # 3) and the LTE-U eNB1 or the cell of operator A (eg, It may be detected that a PCI conflict has occurred between Cell # 2).

  If the LTE-U eNB 1 detects a PCI conflict in block 502, it may perform the processing shown in blocks 503 and 504. In block 503, the LTE-U eNB1 changes the setting (eg, PCI, or ON period) of the cell of the operator A to resolve or avoid the PCI contention. As an example, LTE-U eNB1 changes the PCI of the cell of operator A (eg, Cell # 2) from the same PCI as the cell (eg, Cell # 3) detected by UE 3 to another PCI You may resolve the competition. In another example, LTE-U eNB1 does not overlap the frame timing or ON period of the non-licensed frequency cell (eg, Cell # 2) of operator A with that of the cell (eg, Cell # 3) detected by UE3. By adjusting in such a manner, two cells (eg, Cell # 2 and Cell # 3) using the same PCI and the same frequency may be distinguishable in UE3. If the frame timing or ON period of the cell of operator A (eg, cell # 2) is already different from that of the cell of the non-licensed frequency detected by UE 3 (eg, cell # 3), the processing of block 503 is omitted. May be

  In block 504, the LTE-U eNB 1 serving cell identification information for identifying a cell (eg, Cell # 2 or Cell # 3) of a non-licensed frequency (F2) to be subjected to predetermined processing by UE3. Transmit to UE3 in (Cell # 1).

In one example, the cell identification information specifies at least one of the parameters listed below to identify a cell provided on a non-licensed frequency by LTE-U eNB1 or its operator A as a processing target by UE3. Also good:
・ Non-licensed frequency used by operator A (eg, F2),
・ Cell identifier of operator A's cell (eg, Cell # 2),
The frame timing of the cell of the operator A (eg, Cell # 2), and the ON period of the cell of the operator A (eg, Cell # 2).
Here, the cell identifier may be PCI, another cell identifier different from PCI, or a combination thereof.

In another example, the cell identification information includes at least one of the parameters listed below to identify cells (eg, Cell # 3) of other operators (eg, operator B) as targets for processing by UE3. May be specified:
Cell identifier different from that of operator A,
Frame timing different from the cell of operator A, and ON period different from the cell of operator A.
The cell of the operator A referred to here may be a cell as long as each eNB (LTE-U eNB1) of the operator A is aware of (for example, the cell of the own cell and the adjacent cell list); It does not have to be all the cells of.

  In yet another example, the cell identification information may include the PCI of the cell of the operator A (eg, Cell # 2), the frame timing, etc., in order to specify the cell of the other operator B (Cell # 3) as the processing target by the UE 3. Alternatively, the ON period may be designated. In this case, the UE 3 may perform predetermined processing in PCI, frame timing, or ON period that is not explicitly designated in the cell identification information.

  The cell identification information may specify a plurality of PCIs, a plurality of frame timings, or a plurality of ON periods. The cell specific information may specify a PCI range (eg, 100 to 200) in order to specify a plurality of PCIs.

  Cell specification information may be transmitted to UE3 as individual control information by RRC signaling (message) in a serving cell (Cell # 1), for example. The RRC signaling (message) may be an RRC Connection Reconfiguration message, and the eNB 1 may transmit cell identification information as configuration information (Measurement configuration: MeasConfig) necessary for terminal measurement. Instead of this, the cell identification information may be transmitted in broadcast information (System Information: SI, System Information Block: SIB) of the serving cell (Cell # 1).

  When the cell identification information includes PCI, a list of PCI, or designation of a range of PCI, the cell identification information can be referred to as PCI information (PCI information).

The predetermined process performed by the UE 3 may include at least one of the processes listed below.
・ Cell search processing (cell search)
・ Cell selection processing (cell selection)
・ Cell reselection process (cell reselection)
・ Proximity estimation
・ Proximity indication
・ Terminal measurement (RRM measurement)
・ Report of terminal measurement result (RRM measurement report)
・ Radio quality measurement (CQI measurement)
・ Report of radio quality measurement result (CQI report)
-Channel state measurement (CSI measurement)
・ Report of channel state measurement result (CSI report)
・ Sensing (CCA, energy detection)

Targeting a cell to cell search processing means selecting a sequence of PSS and SSS of the cell as a search candidate in the cell search function. The cell search process may be to search (search) whether or not the cell exists for at least one of the following purposes:
(A) using as a serving cell (eg SCell),
(B) check whether cells of other operators exist or not;
(C) performing interference measurement from cells of other operators (inter-operator measurement, inter-operator cell interference measurement, inter-network measurement, or inter-network interference measurement), and (d) sensing (eg CCA, Do energy detection).

  The detection of the proximity to the cell is, for example, at least one of the above-mentioned (a) to (d), and the UE 3 autonomously confirms (estimates) whether or not the target cell exists in the periphery (nearby). It may be to do. The detection of proximity to a cell can also be referred to as proximity estimation to a cell, detection of cell availability, or simply cell discovery. Detection of proximity to a non-serving cell (non-serving cell) in a non-licensed frequency by UE 3 may be, for example, a cell specific signal transmitted from the radio base station (LTE-U eNB) 1 in the non-serving cell. Including detecting. The cell specific signal includes known symbols or known sequences. The cell specific signal may be, for example, a synchronization signal (Synchronization Signal, in LTE, PSS and SSS) or a reference signal (Reference Signal: RS), or basic information (Master Information Block: MIB) or system broadcast in the cell. It may be information (System Information Block: SIB, for example, SIB1 or SIB2, or SIBx defined for LTE-U). In this case, UE3 determines whether the reception quality (eg, RSRP, RSRQ, RSSI, SINR, or CQI) of the cell specific signal (eg, RS) is equal to or higher than a predetermined threshold (or is higher than the threshold), for example. The proximity to the non-attribution cell may be detected based on Alternatively, the UE 3 may detect proximity to the non-attributable cell based on whether or not the basic information (MIB) or system information (SIB) broadcasted in the non-attributable cell is correctly received. Good. The reference signal may be, for example, a cell specific reference signal (CRS), a reference signal (CSI RS) for measurement report of channel state information (CSI), and a reference signal for cell detection (CRS). Discovery RS: DRS) may be included. The DRS may be, for example, a combination of two or more of PSS, SSS, CRS, and CSI RS, or may be a newly defined reference signal for cell detection.

  The report of the proximity to the cell includes reporting the result of the detection of the proximity to the above-mentioned cell to the LTE-U eNB1 on the serving cell (eg, PCell) of the license frequency. The report may be transmitted from the UE 3 to the LTE-U eNB 1 as a Radio Resource Control (RRC) message. The report may include timing information in addition to the cell identifier (eg, PCI) to identify cells of the detected non-licensed frequency. The timing information relates to the reception of the downlink signal at the wireless terminal, and indicates the relationship between the frame timing of the detected cell and that of the serving cell. The timing information may indicate the difference (eg, time difference, or subframe number difference) between the frame timing of the detected cell and that of the serving cell.

  FIG. 6 is a flowchart illustrating an example (process 600) of the process performed by the UE 3. Process 600 illustrates the operation of UE 3 upon receiving the cell identification information described in block 504 of FIG. In block 601, the UE 3 receives cell identification information for identifying a cell of a non-licensed frequency (F2) in the serving cell (Cell # 1) from the LTE-U eNB1. In block 602, the UE 3 performs predetermined processing on a cell of a non-licensed frequency (F2) identified according to cell identification information. The cell identification information and the predetermined processing performed by the UE 3 are as described above. According to the procedures of FIGS. 5 and 6, it is possible to resolve or avoid PCI contention and appropriately identify a cell to be subjected to processing performed by UE 3 among a plurality of cells using non-licensed frequencies. it can.

  As understood from the above description, the UE 3 according to the present embodiment can use information useful for detecting PCI contention (that is, timing information regarding frame timing or ON period) to a network (eg, eNB 1 or other control node Can be provided). Therefore, according to this embodiment, the UE 3 can support detection of PCI contention by the network, that is, PCI collision or PCI confusion.

Second Embodiment
In the first embodiment described above, an example of the LTE-U according to the LAA scheme that performs CA on the license frequency and the non-license frequency has been described. In the present embodiment, a case will be described in which the LTE-U eNB and the UE have a dual connectivity (DC) function. FIG. 7 is a view showing an example of the configuration of a wireless communication system according to the present embodiment. The radio base stations (eNBs) 4 and 5 and the radio terminal (UE) 7 have a dual connectivity function. Dual Connectivity is provided by (that is, managed by) a main base station (master base station, Master eNB: MeNB) 4 and a sub base station (secondary base station, Secondary eNB: SeNB) 5 for respective radio resources (that is, , Or a cell or carrier) at the same time. In the example of FIG. 7, MeNB4 and SeNB5 are connected via the X2 interface, MeNB4 manages Cell # 1 of license frequency F1, and SeNB5 controls Cell # 2 of license frequency F2 and Cell # 3 of non-license frequency F3. to manage. MeNB4 and SeNB5 operate | move as a normal LTE eNB for UE which does not perform DC, and can communicate with UE independently in Cell # 1 and Cell # 2, respectively.

  The UE 7 supporting DC can perform carrier aggregation (CA) using at the same time a plurality of cells with different frequencies managed by the MeNB 4 and the SeNB 5 as serving cells. A set of serving cells managed by the MeNB 4 is called a master cell group (MCG), and a set of serving cells managed by the SeNB 5 is called a secondary cell group (SCG). The MCG includes at least a Primary Cell (PCell), and may further include one or more Secondary Cells (SCell). The SCG includes at least a Primary SCell (abbreviated as pSCell or PSCell), and may further include one or more SCells. The pSCell is a cell to which at least an uplink physical control channel (Physical Uplink Control CHannel: PUCCH) is assigned, and which has a role like PCell in the SCG.

The following briefly describes Dual Connectivity (DC). For details of Dual Connectivity, see, for example, Non-Patent Document 5. The MeNB 4 holds a connection (S1-MME) of a core network (Evolved Packet Core: EPC) with a mobility management apparatus (MME) of the UE 7 that executes DC. Therefore, MeNB4 can be called the mobility management point (or mobility anchor) of UE7. Therefore, control information of Control Plane (CP) is transmitted and received between MeNB 4 and UE 7 in the MCG. Control information of CP related to SCG of SeNB5 is transmitted and received between SeNB5 and MeNB4 (X2 interface), and further transmitted and received between MeNB4 and UE7 in MCG. For example, Radio Resource Configuration (eg, Radio Resource Profile Dedicated IE) of SCG is transmitted from SeNB 5 to MeNB 4 in an inter-node RRC message called SCG-Configuration, and transmitted from MeNB 4 to UE 7 in RRC Connection Reconfiguration message. On the other hand, UE7 terminal capability information (UE-EUTRA capabilities IE), SCG security information (eg SK _eNB ), MCG's Radio Resource Configuration (eg Radio Resource Config Dedicated IE), etc. are MeNB4 with inter-node RRC message called SCG-ConfigInfo To SeNB5.

  In DC, three configurations are supported from the viewpoint of User Plane (UP) bearer setting. The first is the MCG bearer. In order to use only resources (eg, MCG) of MeNB4, the MCG bearer is a bearer in which a radio protocol is allocated only to MeNB4, and a gateway apparatus (Serving Gateway (S The connection (S1-U) is maintained between the GW and the Packet Data Network Gateway (P-GW) and the MeNB 4. The second is the SCG bearer. The SCG bearer is a bearer in which the radio protocol is allocated only to SeNB5 in order to use only the resource (eg SCG) of SeNB5, and a connection is established between the gateway device (S-GW or P-GW) and SeNB5 ( S1-U) is held. The third is the Split bearer. Split bearer is a bearer in which a radio protocol is arranged in both MeNB 4 and SeNB 5 in order to use resources (e.g. MCG and SCG) of both MeNB 4 and SeNB 5. In the Split bearer, the connection (S1-U) is maintained between the gateway device (S-GW or P-GW) and the MeNB 4, and UP data (eg PDCP PDU) transmitted by SCG, for example, is MeNB4 via X2 Are transferred to SeNB5. When performing LAA in SeNB5 and UE7 which are performing DC, the cell of a non-licensed frequency is used as SCell with PSCell of SCG, for example. At this time, in the cell of the non-licensed frequency, a radio bearer (Radio Bearer) corresponding to the SCG bearer or the Split bearer is established.

  FIG. 8 shows an example of a situation where multiple cells provided by different LTE operators use the same PCI. In the example of FIG. 8, the MeNB 4 and the SeNB 5 supporting dual connectivity are managed by the operator A. Cell # 3 of the unlicensed frequency (F3) has PCI # 5. On the other hand, the LTE-U eNB 6 is managed by another operator B different from the operator A, and operates Cell # 4 at the non-licensed frequency F3. In the example of FIG. 8, PCI collision occurs because Cell # 3 and Cell # 4 are adjacent to each other and have the same PCI # 5. Although Cell # 3 and Cell # 4 having the same PCI # 5 are not adjacent to each other, they may be arranged to be adjacent to Cell # 2, and in this case, PCI confusion occurs.

  Information useful for detecting PCI contention (ie, frame timing or cell information) to support detection of PCI contention by the network (eg, eNB1 or other control node) described in the first embodiment The technique of transmitting timing information (for timing of detection) from the UE 3 to the network can also be applied to the case of Dual Connectivity shown in FIG. The above-mentioned serving cell may be a cell of MeNB 4 (MCG; E.g., PCell) or a cell of SeNB 5 (SCG: E.g., PSCell). However, SFN may be synchronized or may not be synchronized between the MCG of MeNB 4 and the SCG of SeNB 5. When the SFN is not synchronized and the serving cell on which the timing information is generated is the cell (eg, PCell) of MeNB4, the UE 7 generates timing information in consideration of the difference between the MCG and SCG SFN. The timing information may be generated for the SFN of the cell (eg, PCell) of the MeNB 4 serving as the reference. In the latter case, UE 7 may also report the difference in SFN to MeNB 4.

  Moreover, UE7 may transmit the timing information of the cell detected in the non-licensed frequency (F3) to SeNB5 in SCG, and may transmit to MeNB4 in MCG. In the latter case, the MeNB 4 may transfer the timing information to the SeNB 5 using, for example, SCG-ConfigInfo. Furthermore, the UE 7 may receive cell identification information for identifying a cell to be a target of predetermined processing in the cell (SCG) of the SeNB 5 or may receive in the cell (MCG) of the MeNB 4. Moreover, SeNB5 may produce | generate cell specification information and MeNB4 may produce | generate. In the former case, SeNB5 may transfer the generated cell identification information to MeNB4 in SCG-Configuration, for example, and MeNB4 may transmit to UE7.

  Finally, configuration examples of the radio terminals (UE3, UE7) and the radio base stations (LTE-U eNB1, MeNB4, SeNB5) according to the above-described embodiment will be described. Each of the radio terminals (UE3, UE7) described in the above embodiments may also include a transceiver for communicating with a radio base station (LTE-U eNB1, MeNB4, SeNB5), and a controller coupled to the transceiver. Good. The controller executes the process related to the wireless terminal (UE3, UE7) described in the above embodiment (for example, the process of discriminating the cell of the non-licensed frequency based on the relationship between the frame timing thereof and the frame timing of the serving cell) .

  Each of the radio base stations (LTE-U eNB1, MeNB4, SeNB5) described in the above embodiments may also include a transceiver for communicating with the radio terminals (UE3, UE7) and a controller coupled to the transceiver. Good. The controller performs the processing (for example, transmission of the set value of the predetermined offset to UE3 or UE7, the timing received from UE3 or UE7) regarding the radio base station (LTE-U eNB1, MeNB4, SeNB5) described in the above-mentioned embodiment Perform information based PCI conflict detection).

  FIG. 9 is a block diagram showing a configuration example of the radio terminal (UE) 3 according to the first embodiment. The wireless terminal 7 according to the second embodiment may have the same configuration as that shown in FIG. Referring to FIG. 9, UE 3 includes a wireless transceiver 3001, a processor 3002, and a memory 3003. The wireless transceiver 3001 is configured to communicate with the LTE-U eNB1.

  The processor 3002 reads the software (computer program) from the memory 3003 and executes it to perform the processing of the UE 3 regarding the processing 300 or 600 described in the above embodiment. The processor 3002 may be, for example, a microprocessor, a micro processing unit (MPU), or a central processing unit (CPU). The processor 3002 may include multiple processors.

  The memory 3003 is configured by a combination of volatile memory and non-volatile memory. Volatile memory is, for example, static random access memory (SRAM) or dynamic RAM (DRAM) or a combination thereof. The non-volatile memory is, for example, a mask read only memory (MROM), a programmable ROM (PROM), a flash memory, or a hard disk drive, or a combination thereof. Also, the memory 3003 may include storage located remotely from the processor 3002. In this case, the processor 3002 may access the memory 3003 via an I / O interface not shown.

  The memory 3003 may be used to store one or more software modules including instructions and data for performing the processing of the UE 3 regarding the processing 300 or 600 described in the above embodiments. The processor 3002 can perform the processing of the UE 3 described in the above embodiments by reading out the one or more software modules from the memory 3003 and executing the software module.

  FIG. 10 is a block diagram showing a configuration example of the radio base station (LTE-U eNB) 1 according to the first embodiment. The radio base stations 4 and 5 according to the second embodiment may have the same configuration as that of FIG. Referring to FIG. 10, the LTE-U eNB 1 includes a wireless transceiver 1001, a network interface 1002, a processor 1003, and a memory 1004. The wireless transceiver 1001 is configured to communicate with the UE 3. Network interface 1002 is used to communicate with network nodes (eg, MME and S-GW). The network interface 1002 may include, for example, a network interface card (NIC) compliant with the IEEE 802.3 series.

  The processor 1003 reads the software (computer program) from the memory 1004 and executes it to perform the processing of the LTE-U eNB 1 regarding the processing 500 described in the above-described embodiment. The processor 1003 may be, for example, a microprocessor, an MPU, or a CPU. The processor 1003 may include multiple processors.

  The memory 1004 is configured by a combination of volatile memory and non-volatile memory. Volatile memory is, for example, SRAM or DRAM or a combination thereof. The non-volatile memory is, for example, an MROM, a PROM, a flash memory, or a hard disk drive, or a combination thereof. Memory 1004 may include storage located remotely from processor 1003. In this case, the processor 1003 may access the memory 1004 via the network interface 1002 or an I / O interface not shown.

  The memory 1004 may be used to store one or more software modules including instructions and data for performing the processing of the LTE-U eNB1 regarding the processing 500 described in the above embodiments. The processor 1003 can perform the processing of the LTE-U eNB 1 described in the above-described embodiment by reading and executing the one or more software modules from the memory 1004.

  As described with reference to FIG. 9 and FIG. 10, each of the processors possessed by the UEs 3 and 7 and the eNBs 1, 4 and 5 according to the above embodiments causes the computer to execute the algorithm described using the drawings. One or more programs including a group of instructions may be executed. These programs can be stored and supplied to a computer using various types of non-transitory computer readable media. Non-transitory computer readable media include tangible storage media of various types. Examples of non-transitory computer readable media include magnetic recording media (eg, flexible disks, magnetic tapes, hard disk drives), magneto-optical recording media (eg, magneto-optical disks), Compact Disc Read Only Memory (CD-ROM), CD- R, CD-R / W, semiconductor memory (for example, mask ROM, Programmable ROM (PROM), Erasable PROM (EPROM), flash ROM, Random Access Memory (RAM)). Also, the programs may be supplied to the computer by various types of transitory computer readable media. Examples of temporary computer readable media include electrical signals, light signals, and electromagnetic waves. The temporary computer readable medium can provide the program to the computer via a wired communication path such as electric wire and optical fiber, or a wireless communication path.

<Other Embodiments>
The plurality of embodiments described above may be implemented independently of one another or may be implemented in combination as appropriate.

  In the above embodiment, for convenience of explanation, the description has been made using the figures (FIG. 2, FIG. 7, etc.) in which only a plurality of cells using the same PCI as the cell of the non-licensed frequency are shown. These figures are only an example. That is, in the above-described embodiment, at least one cell in which no PCI contention occurs may be operated at the non-licensed frequency, and UEs 3 and 7 execute the process 300 or 600 described above for these at least one cell. Etc. may be performed. Furthermore, in the above embodiment, multiple frequencies (carriers or channels) may be available at non-licensed frequencies, and UEs 3 and 7 may use all of those multiple frequencies or frequencies specified by LTE-U eNB The processing 300 or 600 may be performed on the target.

  For example, in addition to Cell # 2 (PCI # 5) and Cell # 3 (PCI # 5) shown in FIG. 2, UE 3 when there is Cell # 4 (PCI # 6) having a PCI different from these. (I) PCI # 5 and its frame timing corresponding to Cell # 2, and (ii) PCI # 5 and its frame timing corresponding to Cell # 3, detected at a non-licensed frequency (F2), and (iii ) The PCI # 6 corresponding to the Cell # 4 and its frame timing may be detected, and these may be reported to the LTE-U eNB1. Instead, UE3 does not report (i) PCI # 5 corresponding to Cell # 2 and its frame timing and (ii) PCI # 5 corresponding to Cell # 3 and its frame timing to LTE-U eNB1. In (iii), PCI # 6 corresponding to Cell # 4 and its frame timing may be reported to LTE-U eNB1. In these examples, LTE-U eNB 1 receives the report from UE 3 and estimates Cell # 4 that PCI contention does not occur more than Cell # 2 that may have PCI contention. It may be selected as a secondary cell (SCel) of CA preferentially.

  The PCI described in the above embodiment is an example of a cell identifier (physical identifier). For example, in non-licensed frequency cells, contention for other cell identifiers different from PCI may occur. In some implementations, the identifier of the unlicensed frequency cell may be a Virtual Cell ID. The Virtual Cell ID may be, for example, a scrambling code identifier (eg, Scrambling Identity, or Scrambling Code ID) used for transmission of a reference signal in a cell of the non-licensed frequency. Also, in some implementations, the identifier of the cell of the non-licensed frequency may be an identifier different from the PCI defined by newly assigning a cell number or cell index to the cell of the non-licensed frequency. These identifiers may be used instead of or in combination with PCI.

  In the above embodiments, the case of the LAA has been described. That is, in the first embodiment, the radio base station (LTE-U eNB) 1 and the radio terminal (UE) 3 use the cell of the license frequency as a primary cell (PCell), and the cell of the non-license frequency is a secondary cell The carrier aggregation (CA) used as (SCell) has been mainly described. In 2nd Embodiment, MeNB4 and SeNB5 used the license frequency, and SeNB5 mainly demonstrated Dual Connectivity (DC) which uses a non-license frequency. However, in the first embodiment, the radio base station (LTE-U eNB) 1 uses a shared frequency (for example, F3) as a PCell, and a narrow sense non-licensed frequency (for example, F2) or another shared frequency (for example, Carry aggregation (CA) may be performed using F4) as a secondary cell (SCell). Here, the narrow sense non-licensed frequency means a frequency which is not assigned to any operator (ie, a frequency which is not a license frequency and is not a shared frequency). Similarly, in the second embodiment, for Dual Connectivity (DC), MeNB 4 may use a shared frequency and SeNB 5 may use a shared frequency or non-licensed frequency in a narrow sense.

  Furthermore, PCI conflicts may occur in various situations as well as situations where multiple LTE operators use non-licensed frequencies (or licensed shared frequencies) for LAA or LSA. PCI conflicts, or PCI collisions or PCI confusions, can occur when using any of unlicensed frequency, licensed shared frequency, and licensed frequency, and can occur among multiple operators and within one operator. Either can happen. The technique of transmitting timing information on frame timing or detection timing of a detected cell and PCI of the cell to the eNB described in the above embodiment applies to various cases where PCI contention occurs. be able to.

  Furthermore, as already mentioned, PCI confusion can also occur when multiple cells use different frequencies, but they use the same PCI. The technique for transmitting timing information related to frame timing or detection timing of a detected cell and the PCI of the cell to the eNB described in the above embodiment is a method for transmitting PCI between a plurality of cells using different frequencies. It can be applied to the case where confusion occurs.

  Moreover, in the above-mentioned embodiment, it mainly demonstrated regarding the LTE system. However, as already mentioned, these embodiments may be applied to wireless communication systems other than LTE systems, such as 3GPP UMTS, 3GPP2 CDMA2000 system (1xRTT, HRPD), GSM / GPRS system, or WiMAX system etc. Good. A radio base station (eNB) having a function of performing LTE communication on a non-licensed frequency and RRH / RRE are called radio base stations (LTE-U eNB). Similarly, in other systems, it is possible to introduce a network device capable of communicating on a plurality of frequencies (for example, license frequency and non-license frequency), and they can be generically called a radio station. That is, the radio station corresponds to the radio base station (eNB) and the RRH / RRE in LTE as described above, corresponds to the base station (NodeB: NB) and the base station controller (RNC) in UMTS, and further CDMA2000 The system corresponds to a base station (BTS) and a base station controller (BSC). Furthermore, particularly in the example of Dual Connectivity (DC), a base station system including a main base station (MeNB in LTE) and a sub base station (SeNB in LTE) can be referred to as a wireless station. Each of the main base station and the sub base station can be referred to as a wireless communication node.

  In wireless communication systems other than LTE, other cell identifiers different from PCI are used (e.g. PSC used in 3GPP UMTS), and contention of these cell identifiers may occur as well as PCI conflicts. . The technique of transmitting timing information on frame timing or detection timing of a detected cell and PCI of the cell to the eNB described in the above embodiment causes contention of other cell identifiers such as PSC. It can be applied to various cases.

  Also, in the above-described embodiment, a serving cell (eg, Cell # 1 in FIG. 2) and a plurality of cells configured to use the same cell identifier and the same frequency as each other (eg, Cell # 2 in FIG. 2 and Cell # 3) may use different Radio Access Technologies (RATs). For example, the serving cell may be an LTE (E-UTRAN) cell, and the plurality of cells different from the serving cell may be a UMTS (UTRAN) cell.

  Furthermore, the embodiment described above is only an example regarding application of the technical idea obtained by the present inventor. That is, the said technical thought is not limited only to embodiment mentioned above, Of course, various change is possible.

1, 4, 5 wireless base station 3, 7 wireless terminals 0011, 3001, wireless transceiver 1002 network interface 1003, 3002 processor 1004, 3003 memory

Claims (18)

A wireless terminal,
With at least one processor,
The at least one processor is
Communicate with the radio station in the serving cell using the first frequency,
Detect at least one cell using the second frequency;
A cell identifier of the detected at least one of the at least one cell timing being information and the detection of cells, and transmits at the serving cell to the radio station,
Is configured,
The timing information indicates a detection time or a detection period at which the at least one detected cell is detected by the wireless terminal.
Wireless terminal. The at least one processor is further configured to receive cell identification information transmitted in the serving cell from the wireless station in response to the timing information and the cell identifier transmitted by the wireless terminal.
The cell identification information may be (a) a cell of the detected at least one cell to identify a first cell provided at the second frequency by the wireless station or an operator managing the wireless station. At least one of a cell identifier different from the identifier, (b) a frame timing different from the frame timing of the detected at least one cell, and (c) an ON period different from the ON period of the detected at least one cell Show one ,
The wireless terminal according to claim 1 . The first frequency is a license frequency licensed to the radio station or an operator who manages the radio station,
The second frequency is a non-licensed frequency,
A wireless terminal according to claim 1 or 2 . An apparatus disposed in a network including a radio station,
With at least one processor,
The at least one processor is
Communicate with the wireless terminal in the serving cell of the wireless terminal using the first frequency,
A cell identifier of the at least one cell the second is at least one cell of the timing information and the detection is detected in the frequency by the wireless terminal, receiving from the wireless terminal in the serving cell,
Is configured,
The timing information indicates a detection time or a detection period at which the at least one detected cell is detected by the wireless terminal.
apparatus. The at least one processor is further provided by the radio station or an operator managing the radio station at the second frequency based on the cell identifier of the detected at least one cell and the timing information. Configured to detect a cell identifier conflict between a first cell and the at least one detected cell,
An apparatus according to claim 4 . The at least one processor may be configured such that the cell identifier of the detected at least one cell matches that of the first cell, but the detection time or detection period of the detected at least one cell is the Detecting that there is a cell identifier conflict between the at least one detected cell and the first cell, if not aligned with the ON period of one cell;
An apparatus according to claim 5 . The at least one processor is further configured to transmit cell specific information in the serving cell to the wireless terminal;
The cell identification information may be (a) a cell identifier different from the cell identifier of the detected at least one cell to identify the first cell, (b) a frame of the detected at least one cell indicating at least one of the different ON periods different frame timing, and (c) the ON period of at least one cell said are detected timing,
An apparatus according to claim 5 or 6 . The at least one processor is further configured to adjust a cell identifier, frame timing, or ON period of the first cell to be different than a corresponding one of the detected at least one cell.
An apparatus according to any one of claims 5 to 7 . The first frequency is a license frequency licensed to the radio station or an operator who manages the radio station,
The second frequency is a non-licensed frequency,
Apparatus according to any one of claims 4-8. A method performed by the wireless terminal,
Communicating with a wireless station in a serving cell using the first frequency;
Detecting at least one cell using a second frequency, and the cell identifier of the detected at least one of the at least one cell timing being information and the detection of the cell, to the radio station in the serving cell To send,
Equipped with
The timing information indicates a detection time or a detection period at which the at least one detected cell is detected by the wireless terminal.
Method. And receiving cell identification information transmitted in the serving cell from the wireless station in response to the timing information and the cell identifier transmitted by the wireless terminal.
The cell identification information may be (a) a cell of the detected at least one cell to identify a first cell provided at the second frequency by the wireless station or an operator managing the wireless station. At least one of a cell identifier different from the identifier, (b) a frame timing different from the frame timing of the detected at least one cell, and (c) an ON period different from the ON period of the detected at least one cell Show one ,
A method according to claim 10 . A method performed by a network including a radio station,
And a wireless terminal, to communicate in the serving cell of the wireless terminal using a first frequency, and said at least one cell are detected in the second frequency by the wireless terminal timing information and said detected at least one Receiving a cell identifier of a cell from the wireless terminal at the serving cell;
Equipped with
The timing information indicates a detection time or a detection period at which the at least one detected cell is detected by the wireless terminal.
Method. A first cell provided at the second frequency by the radio station or an operator managing the radio station based on the cell identifier of the at least one cell detected and the timing information; Further comprising detecting a cell identifier conflict with at least one cell,
A method according to claim 12 . In the detecting, the cell identifier of the detected at least one cell matches that of the first cell, but the detection time or the detection period of the detected at least one cell is the Detecting that there is a cell identifier conflict between the at least one detected cell and the first cell if not aligned with the ON period of the first cell,
The method of claim 13 . Further comprising transmitting cell identification information to the wireless terminal in the serving cell,
The cell identification information may be (a) a cell identifier different from the cell identifier of the detected at least one cell to identify the first cell, (b) a frame of the detected at least one cell indicating at least one of the different ON periods different frame timing, and (c) the ON period of at least one cell said are detected timing,
A method according to claim 13 or 14 . Adjusting the cell identifier, frame timing, or ON period of the first cell to be different than the corresponding one of the detected at least one cell.
The method according to any one of claims 13-15. A program for causing a computer to perform the method according to claim 10 or 11 . Program for causing a method according to the computer in any one of claims 12 to 16.

Images