JP6179742B2 - UE (User Equipment), base station, and communication method - Google Patents

Description

  The present invention generally relates to a wireless communication system, and more particularly to a technique for controlling a feedback operation of a user terminal in a coordinated multi-point (CoMP) transmission / reception scheme.

  As described in Section 4 of Non-Patent Document 1, cooperative multipoint transmission / reception is performed in LTE (Long Term Evolution) -Advanced Release 11 (Rel. 11), with high data rate coverage and improved cell edge throughput. At the same time, it is being studied as a tool for improving system throughput. As described in Section 5.1.3 of Non-Patent Document 1, CoMP method, joint transmission (JT), dynamic point selection (DPS), and cooperative scheduling / cooperative It has been agreed that beamforming (coordinated scheduling / coordinated beamforming, CS / CB) should be supported. For JT and DPS, data for user equipment (UE) is available at multiple points in a CoMP cooperating set. CoMP cooperating set is a set of points that are directly and / or indirectly involved in data transmission to UEs in time-frequency resources in Section 5.1.4 of Non-Patent Document 1. It is prescribed as In the case of CS / CB, the data for the UE is only available at one point (serving point) and transmitted from it, but the user scheduling / beamforming decision is between the points corresponding to the CoMP cooperating set. Done cooperatively. Note that in cooperative multipoint transmission / reception, the term “point” can be used as a base station, a Node B or eNB radio station, a transmission / reception unit, a remote radio equipment (RRE), or a distributed antenna. Should. Therefore, in this specification, a point, a radio station, a transmission / reception unit, and a cell may be used as synonyms.

  In the case of JT, a plurality of transmission points (TP) are selected for simultaneous data transmission, and interference comes from points other than the selected TP. In the case of DPS, only one TP is selected dynamically, and interference comes from points other than that only one selected TP. In the case of CB / CS, the serving point is the only TP that transmits data, but strong interference from neighboring cells is greatly reduced. Therefore, various types of interference occur due to the use of different CoMP schemes.

  As described in Section 5.2.2 of Non-Patent Document 1, it has been decided to standardize a common feedback framework that can support CoMP JT, DPS, and CB / CS. For channel dependent scheduling that supports all the above CoMP schemes, Section 5.1.4 of Non-Patent Document 1 describes that the CoMP measurement set includes channel state / statistical information (channel State / statistical information (CSI) is defined as a set of points that are measured and / or reported. Here, it is necessary to estimate channel quality information (CQI) in consideration of interference power with muting in different cells in the CoMP measurement set on the UE side and feed back from the UE to the network.

  Rel. In 8/9, a cell-specific reference signal (CRS) is used for CSI measurement. Interference measurements remain completely unspecified with respect to UE behavior. Rel. 10 introduces non-zero power CSI-RS and zero power CSI-RS for CSI measurement of single cell downlink transmission as described in Section 6.10.5.2 of Non-Patent Document 2. Has been. Rel. In 11 CoMP work items (WI), it is proposed to use multiple non-zero power CSI-RSs for orthogonal resources to measure signals from multiple points in a CoMP measurement set. ing.

  Further, in order to measure interference within a CoMP cluster and between CoMP clusters by setting a variable muting pattern for a point in the CoMP measurement set, zero power CSI-RS in Non-Patent Document 3 and Non-Patent Document 4 are used. It has also been proposed to specify an interference measurement resource such as a PDSCH muting resource element (RE).

  According to Section 6.3.2 of Non-Patent Document 5, the serving point is used as an information element of CSI-RS-Config by radio resource control (RRC) signaling as non-zero power CSI-RS and zero power. Only the resource location of CSI-RS, i.e., resource element (RE) index and subframe index, is semi-statically notified to UE. In the case of multipoint signal power measurement by using a plurality of non-zero power CSI-RS, the non-zero power CSI-RS is generated by using a cell-specific scrambling sequence as described in Non-Patent Document 6. When done, additional information such as cell identity (ID) of each cell in the CoMP measurement set may also be needed for UE detection. In this case, as specified in Section 6.8.2 of Non-Patent Document 2, the physical cell ID is used to generate the initialization value of the cell-specific scrambling sequence.

  In order to explain the problems to be solved by the present invention, a simple example of a system using CoMP is shown in FIG. In FIG. 1, it is assumed that the UE is served by cell 1 and the CoMP measurement set consists of a serving cell (cell 1) and cooperating cells (cell 2 and cell 3). Cell 1, cell 2 and cell 3 are managed by a central control unit (CCU) through backhaul links BL1, BL2 and BL3, respectively.

  As shown in FIG. 2A, the CCU sets orthogonal non-zero power CSI reference signals CSI-RS1, CSI-RS2, and CSI-RS3 for cell 1, cell 2, and cell 3, respectively. In addition, zero power CSI reference signals ZP-CSI-RSa, ZP-CSI-RSb, ZP-CSI-RSc and ZP-CSI-RSd are also set to measure interference with muting in different cells. Here, the muting patterns for different zero power CSI-RS resources are denoted by Ma, Mb, Mc and Md, respectively. In the muting pattern Ma, the signal powers of the cells 1 and 2 are muted. In the muting pattern Mb, the signal powers of the cells 1 and 3 are muted. In the muting pattern Mc, the signal powers of the cells 2 and 3 are muted. In the muting pattern Md, the signal power of the cells 1 to 3 is muted. When the signal power of a cell is muted, interference from that cell can be removed from consideration for interference at the UE. Therefore, in the muting pattern Md, all interference in the CoMP measurement set is eliminated.

As shown in FIG. 2B, the UE is notified of the setting information of CSI-RS1, CSI-RS2, and CSI-RS3 including the resource position defined by the RE index and the subframe index together with the corresponding cell ID. Based on the configuration information, the UE can measure the signal power S1, S2 and S3 for each cell. Further, using the knowledge of the zero-power (ZP) -CSI-RSa, ZP-CSI-RSb, ZP-CSI-RSc and ZP-CSI-RSd resource locations, the UE -Interference powers Ia, Ib, Ic, Id can be calculated according to the muting patterns Ma, Mb, Mc and Md by measuring and averaging the received power at the notified position of the CSI-RS.
Muting pattern Ma: Ia = average (0 + 0 + S3 + N)
Muting pattern Mb: Ib = average (0 + S2 + 0 + N)
Muting pattern Mc: Ic = average (S1 + 0 + 0 + N)
Muting pattern Md: Ia = average (0 + 0 + 0 + N)
N represents the sum of interference from outside the CoMP measurement set and additive white Gaussian noise (AWGN).

  Then, the CQI for each CSI-RS resource considering the muted interference for CoMP can be calculated at the UE as shown in FIG. 2C.

  Since the network only informs the UE of the CSI-RS RE location, the UE cannot know which cell's signal is included for the CQI calculation, and therefore CQI as shown in FIG. 2C. Use all interferences to calculate For example, the signal power S1 for cell 1 measured by the UE is not muted in the muting pattern Mc, so the calculation Ic = aver (S1 + N) does not reflect the actual interference in the CSI-RS1 resource.

  However, since only the RE position of CSI-RS is notified to the UE, it is assumed that the calculation Ic = aver (S1 + N) is included, and as a result, an erroneous CQI such as S1 / Ic is obtained. A similar case also occurs when S2 / Ib = S2 / average (S2 + N) and S3 / Ia = S2 / average (S3 + N) are measured and reported, as shown in FIG. 2C. Incorrect CQI calculation and feedback can result in wasted power consumption and unnecessary feedback overhead.

3GPP TR 36.819 v11.0.0, Coordinated multi-point operation for LTE physical layer aspects (Release 11) 3GPP TS 36.211 v10.3.0, Physical Channels and Modulation of Evolved Universal Terrestrial Radio Access (E-UTRA) (Release 10) R1-114260, Ericsson, ST-Ericsson R1-114228, Samsung 3GPP TS 36.331 v10.3.0, Radio resource control (RRC) and Protocol specification of Evolved Universal Terrestrial Radio Access (E-UTRA) (Release 10) R1-114318, Nokia Siemens Networks, Nokia

An object of the present invention is to provide a UE (User Equipment), a base station, and a communication method that enable efficient measurement and feedback of CQI for CoMP scheduling.

A UE (User Equipment) according to the present invention indicates a first resource for interference measurement (hereinafter referred to as CSI-IM (Channel State Information-Interference Measurement) resource) associated with a CQI (Channel Quality Indicator) value . A receiver for receiving information and second information indicating a resource for channel measurement associated with the CQI value (hereinafter referred to as CSI-RS (Channel State Information-Reference Signal) resource ) ; A calculation unit that calculates the CQI value based on an interference measurement result corresponding to the CSI-IM resource and a channel measurement result corresponding to the CSI-RS resource.
The base station according to the present invention includes first information indicating a resource for interference measurement associated with a CQI (Channel Quality Indicator) value (hereinafter referred to as CSI-IM (Channel State Information-Interference Measurement) resource ) , A transmitter for transmitting second information indicating a resource for channel measurement associated with the CQI value (hereinafter referred to as CSI-RS (Channel State Information-Reference Signal) resource ) , and the CSI-IM A receiver that receives the CQI value calculated by a UE (User Equipment) based on an interference measurement result corresponding to the resource and a channel measurement result corresponding to the CSI-RS resource.
A UE (User Equipment) communication method according to the present invention indicates a resource for interference measurement associated with a CQI (Channel Quality Indicator) value (hereinafter referred to as CSI-IM (Channel State Information-Interference Measurement) resource ). Receiving first information and second information indicating a resource for channel measurement associated with the CQI value (hereinafter referred to as CSI-RS (Channel State Information-Reference Signal) resource ) , The CQI value is calculated based on the interference measurement result corresponding to the CSI-IM resource and the channel measurement result corresponding to the CSI-RS resource.
The base station communication method according to the present invention provides a first resource for interference measurement (hereinafter referred to as CSI-IM (Channel State Information-Interference Measurement) resource) associated with a CQI (Channel Quality Indicator) value . information and resources for the association is channel measurement to the CQI value (hereinafter, CSI-RS (channel State information -. Reference Signal) that resource) and sends the second information indicating, wherein the CSI-IM The CQI value calculated by a UE (User Equipment) based on an interference measurement result corresponding to a resource and a channel measurement result corresponding to the CSI-RS resource is received.

  According to the present invention, unnecessary calculation of unrequested CQI on the UE side can be avoided, and unnecessary feedback overhead can be reduced. Thus, power consumption corresponding to unnecessary calculations and feedback is avoided.

  For a more complete understanding of the present invention and its advantages, reference should be made to the following description taken in conjunction with the accompanying drawings. In the drawings, the same reference numerals represent the same parts.

It is a schematic diagram which illustrates an example of the radio | wireless communications system containing UE with the CoMP measurement set. It is a schematic diagram which illustrates the setting of non-zero power CSI-RS and zero power CSI-RS with respect to each cell in a radio | wireless communications system as shown in FIG. It is a schematic diagram which illustrates the resource position notified of the non-zero power CSI-RS and zero power CSI-RS in UE in the radio | wireless communications system as shown in FIG. It is a figure which shows an example of CQI calculation for every CSI-RS. In order to demonstrate the outline | summary of this invention, it is a schematic diagram which illustrates CQI for every setting of non-zero power CSI-RS and ZP-CSI-RS in a network, and CSI-RS resource by which interference in UE was muted. 1 is a block diagram illustrating a wireless communication system according to a first exemplary embodiment. FIG. 5 is a sequence diagram illustrating a first example of operations of a network and a UE in the wireless communication system of FIG. 4. It is a figure which illustrates the RS pair list with respect to the request | requirement CQI contained in the information element in the information element in the CSI-RS setting and RRC signal in 1st Example of FIG. It is a schematic diagram which illustrates the correspondence between the non-zero power CSI-RS and the zero power CSI-RS for the cell 1 in the first embodiment of FIG. It is a figure which illustrates the combination information of RS pair list and CSI-RS setting as shown to FIG. 6A. FIG. 5 is a sequence diagram illustrating a second embodiment of the operation of the network and the UE in the wireless communication system of FIG. 4. It is a figure which illustrates the RS pair list with respect to the non-request | required CQI contained in the information element in the CSI-RS setting information and RRC signal in 1st Example of FIG. It is a schematic diagram which illustrates the correspondence between the non-zero power CSI-RS and the zero power CSI-RS for the cell 1 in the first embodiment of FIG. 2 is a block diagram illustrating a wireless communication system according to a second exemplary embodiment. FIG. FIG. 10 is a sequence diagram illustrating a third embodiment of the operation of the network and UE in the wireless communication system of FIG. 9. It is a figure which illustrates the mute cell ID contained in the information element in the information of the CSI-RS setting and RRC signal in 3rd Example of FIG. FIG. 10 is a diagram illustrating CSI-RS setting information and a correspondence relationship between a muting pattern and a non-muted cell ID in the fourth embodiment of the operation of the network and the UE in the wireless communication system of FIG. 9. FIG. 6 is a schematic diagram illustrating CoMP measurement set changes and corresponding updated CSI-RS and ZP-CSI-RS settings in a wireless communication system according to a third exemplary embodiment of the present invention. It is a table | surface which illustrates RS pair of request | requirement CQI in the case of the updated CoMP measurement set in the radio | wireless communications system by 1st Example. It is a table | surface which illustrates RS pair of non-requesting CQI in the case of the updated CoMP measurement set in the radio | wireless communications system by 2nd Example. 12 is a table illustrating an interference muting pattern having a mute cell index in the case of an updated CoMP measurement set in a wireless communication system according to a third embodiment. 10 is a table illustrating an interference muting pattern having a non-muted cell index in the case of an updated CoMP measurement set in a wireless communication system according to a fourth embodiment. 12 is a table illustrating CQI for each CSI-RS resource with interference muted for an updated CoMP measurement set in a wireless communication system according to a third exemplary embodiment. FIG. 6 is a schematic diagram illustrating a wireless communication system according to a fourth exemplary embodiment.

  Hereinafter, exemplary embodiments of the present invention will be described with reference to the accompanying drawings. The embodiments used to explain the principles of the invention are merely exemplary and should not be construed as limiting the scope of the disclosure in any way. As will be appreciated by those skilled in the art, the principles of the present invention may be implemented in any suitably configured wireless network. The principle of the present invention will be described below with reference to FIG.

  In FIG. 3, the network 10 has cell 1, cell 2 and cell 3, respectively managed by the CCU through backhaul links BL1-BL3, the UE 20 is served by cell 1, and the CoMP measurement set is shown in FIG. As described above, it is assumed that the serving cell 1 and the cooperating cell 2 and the cell 3 are configured. The CCU sets orthogonal non-zero power CSI reference signals CSI-RS1, CSI-RS2, and CSI-RS3 for cell 1, cell 2, and cell 3, respectively. As shown in FIG. 2, in order to measure interference with muting in different cells, zero power CSI reference signals ZP-CSI-RSa, ZP-CSI-RSb, ZP-CSI-RSc and ZP-CSI- RSd is also set.

  According to an exemplary embodiment described below, the network 10 as shown in FIG. 3 notifies the UE 20 of information that indicates the interference measurement resource implicitly or explicitly. That is, the signal indicating the interference measurement resource allows the UE 20 to select an effective pair of CSI-RS and ZP-CSI-RS as illustrated in FIG. Taking the muting pattern Ma as an example, since the signal power of the cell 1 and the cell 2 is muted, interference measurement resources defined by combinations of ZP-CSI-RSa and CSI-RS1 and CSI-RS2 respectively. The information about can be effectively used for CQI calculation. In other words, information on interference measurement resources defined by the combination of ZP-CSI-RSa and CSI-RS3 is not used for CQI calculation. Accordingly, since erroneous CQI calculation and feedback can be effectively avoided, unnecessary feedback overhead is reduced, and CQI for CoMP scheduling is efficiently calculated.

1. First Exemplary Embodiment According to the first exemplary embodiment, an explicit signaling method is used in which the network informs the UE about information about resource pairs enabling CQI calculation. A detailed configuration and operation will be described with reference to FIGS.

1.1) System Configuration As shown in FIG. 4, it is assumed that the wireless communication system according to the first exemplary embodiment includes a network 10 and a UE 20. The network 10 includes a plurality of enhanced Node-Bs (eNBs), and each eNB communicates with the serving radio station 110 (corresponding to the cell 1) through the backhaul links BL1, BL2, and BL3, and other cooperation. A central control unit (CCU) 100 is provided for controlling each of the working radio stations (corresponding to cell 2 and cell 3). Here, the eNB is a centralized station that controls a plurality of cells or low power nodes (LPNs) through a backhaul link. Intra-eNB CoMP is performed in the control area of the eNB. In the case of inter-eNB CoMP, the UE is connected to a plurality of eNBs, and information between the eNBs is exchanged through the X2 backhaul. Below, in order to understand the function of CCU100 better, it illustrates about CoMP in eNB. As described above, in this specification, a point, a radio station, a cell, and a transmission / reception unit are used as synonyms.

  The CCU 100 includes the following functional blocks: a CoMP measurement set determination unit 101, a CSI-RS / muting pattern setting unit 102, an RS pair determination unit 103 that calculates a request or non-request CQI for UE measurement / report, Joint scheduler 104, backhaul link (BL) communication unit 105, and controller 106 for a plurality of transmission points. Each radio station in the CoMP measurement set communicates with the UE 20 and has the following functional blocks: a BL communication unit 111, a controller 112, a radio transmitter 113, and a radio receiver 114. The UE 20 includes the following functional blocks: a radio transmitter 201, a radio receiver 202, a DL signal / interference measurement unit 203, a CQI calculation unit 204, and a controller 205.

  By using the above functional blocks, the network 10 can determine a non-zero power / zero power CSI-RS configuration and a requested or non-requested CQI RS pair for CoMP scheduling. The UE 20 is notified about the CSI-RS setting by the network 10 together with the RS pair list. The UE can measure the interference power with signal power and muting by using the configured non-zero power CSI-RS and zero power CSI-RS, respectively. Thereafter, the UE 20 calculates a request CQI based on the notified RS pair list, and finally feeds back the calculated CQI to the network 10 through the UL channel.

1.2) First Example The first example of the communication method according to the first exemplary embodiment uses the RS pair signaling of the requested CQI. After determining the CSI-RS setting and the required CQI, the network 10 calculates the required CQI by using the signal power measured by the non-zero power CSI-RS and the interference power measured by the zero power CSI-RS. A signal indicating the correspondence relationship between the two is explicitly transmitted to the UE 20. The first embodiment will be described below.

  Referring to FIG. 5, in the network 10, the CoMP measurement set determination unit 101 of the CCU 100 determines a CoMP measurement set for the target UE 20 (operation 301). In this example, the CoMP measurement set includes radio station 110 and cooperating radio stations, namely cell 1, cell 2 and cell 3. Next, as shown in FIG. 3, the CSI-RS / muting pattern setting unit 102 performs non-zero power CSI-RS (CSI-RS1) for cell 1, cell 2 and cell 3 over orthogonal resource elements (RE). , CSI-RS2, CSI-RS3) and different power muting patterns (Ma, Mb, Mc, Md) zero power CSI-RS (ZP-CSI-RSa, ZP-CSI-RSb, ZP-CSI-RSc, ZP-CSI-RSd) is set (operation 302). Thereafter, as shown in FIGS. 6A and 6B, the RS pair determination unit 103 determines an RS pair for calculating the request CQI (operation 303). Under the control of the controller 106, the backhaul link communication unit 105 The RS setting indicator and the RS pair list for the requested CQI are transmitted to the UE 20 via the serving radio station 110 (operation 304). In the RRC signal CSI-RS-Config defined in Non-Patent Document 5, CSI-RS configuration information for non-zero power CSI-RS and zero power CSI-RS in the serving cell is already defined for single point transmission. ing. By using a simple extension, CSI-RS configuration information for multiple non-zero power CSI-RSs and multiple zero power CSI-RSs is illustrated in FIG. 6A. The RS pair list is additional information and should be operated together with the CSI-RS setting. The separate information of the RS pair list and the CSI-RS configuration in FIG. 6A may be combined as the information illustrated in FIG. 6C and transmitted from the network 10 to the UE 20.

  Information on the RS setting is stored as an indicator in the information element of the RRC signal CSI-RS-Config. The RS pair information can also be stored as an indicator in the information element of the RRC signal CSI-RS-Config, or can be stored separately as an indicator in the information element of the RRC signal CQI-Report-Config. It is. Both of these RRC signals are defined in Section 6.3.2 of Non-Patent Document 5. Such an RRC signal is generated by the controller 112 and is semi-statically notified (for example, 120 ms, 240 ms, etc.) to the target UE 20 through the transmitter 113 in the serving radio station 110 (cell 1). The configured non-zero power and zero power CSI-RS (also generated by the controller 112 of each cell in the CoMP measurement set) is periodic with a shorter period (eg, 5 ms, 10 ms, etc.) than the RRC signal. To UE20.

  In the UE 20, when the radio receiver 202 receives the DL signal from the radio station 110, the signal / interference measurement unit 203 detects the non-zero power CSI-RS according to the RRC signal, thereby measuring the signal power for each cell. The interference power with muting is acquired by measuring the reception power at the position of zero power CSI-RS (operation 305). CQI calculation section 204 calculates only the requested CQI according to the notified RS pair list using the measured signal power and the interference power with muting (operation 306). Next, after a UL signal including the calculated CQI and other estimated CSI is generated, PUCCH (physical uplink control channel) or PUSCH (physical uplink shared data channel, physical uplink shared) Is fed back by the wireless transmitter 201 through an uplink channel such as a data channel (operation 307). In the radio station 110, the CQI feedback received by the radio receiver 114 is transferred to the CCU 100 through the backhaul link BL1.

  In CCU 100, upon receiving CQI feedback, controller 106 controls joint scheduler 104 to perform transmission point (TP) selection, resource allocation, and precoding vector selection for each TP (operation 308). The scheduling result is shared by the radio station 110 and the cooperating radio stations (cell 1, cell 2 and cell 3) through the backhaul links BL1-BL3. Finally, downlink control information including a part of the dynamic scheduling result is generated in the serving radio station 110, such as PDCCH (physical downlink control channel) or enhanced PDCCH (enhanced PDCCH, ePDCCH). Sent by the wireless transmitter 113 through the downlink control channel. Based on the dynamic scheduling result, downlink data for the UE 20 is generated by the selected TP radio station and transmitted through the downlink data channel, that is, PDSCH (physical downlink shared data channel). Transmitted by the device 113 (operation 309). As an example, the control signal is transmitted through the PDCCH or ePDCCH only from the serving point. It is also possible to transmit a control signal from a selected TP or a plurality of selected TPs different from the serving point. In that case, the selected TP may be different from the TP for data transmission.

  When the CoMP measurement set is changed due to the movement of the UE 20, the CoMP measurement set determination unit 101 updates the CoMP measurement set for the target UE 20 (operation 310). Since the operations including the operations 311 to 313 after the operation 310 are the same as the operations 302 to 309 as described above, description thereof will be omitted.

1.3) Second Example A second example of the communication method according to the first exemplary embodiment uses RS pair signaling of unsolicited CQI. After determining the CSI-RS configuration and the RS pair of the non-requested CQI, the network 10 explicitly transmits the list of RS pairs of the non-requested CQI to the UE 20 to avoid erroneous CQI calculation. According to the second embodiment, an indicator of the RS pair list of unsolicited CQI is transmitted from the network 10 to the UE 20. This is the main difference between the first embodiment and the second embodiment. Therefore, in the following, the second embodiment will be described mainly with respect to this difference.

  Referring to FIG. 7, in network 10, CoMP measurement set determining section 101 and CSI-RS / muting pattern setting section 102 execute operations 301 and 302, respectively. Thereafter, as shown in FIGS. 8A and 8B, the RS pair determination unit 103 determines an RS pair for the non-requested CQI (operation 303a), and under the control of the controller 106, the backhaul link communication unit 105 performs CSI− The RS setting indicator and the RS pair list for the non-requested CQI are transmitted to the UE 20 via the radio station (operation 304a). Such RS pair list information is included in an information element in the RRC signal CQI-Report-Config or CSI-RS-Config, and is transmitted semi-statically to the UE.

  In the UE 20, the signal / interference measuring unit 203 measures the signal power for each cell and the interference power with muting (operation 305). CQI calculation section 204 calculates CQI by using all combinations of RS pairs other than those of unrequested CQI corresponding to the notified RS pair (operation 306). Thereafter, the UE 20 feeds back the calculated CQI to the network 10 (operation 307).

  In this way, UE 20 does not feed back unsolicited CQI to network 10 by referring to the RS pair indicator for unsolicited CQI, so unnecessary feedback overhead is reduced and CQI for CoMP scheduling is efficient. Is calculated. Compared to the first embodiment, the second embodiment can further reduce the amount of indicators transmitted from the network to the UE.

2. Second Exemplary Embodiment According to the second exemplary embodiment, the network only obtains information about the cell index (ID) of muted interference (mute interference) and non-muted interference (non-muted interference). An implicit signaling method is used that informs the UE 20 and uses this to determine and calculate the required CQI at the UE. A detailed configuration and operation will be described with reference to FIGS.

2.1) System Configuration As shown in FIG. 9, the CCU 100a and the UE 20a are different in functional structure from the CCU 100 and the UE 20 of the first exemplary embodiment shown in FIG. That is, according to the second exemplary embodiment, instead of the CCU 100a, the UE 20a is provided with a function of determining the RS pair of the requested CQI by implicit signaling. This is the main difference between the first and second exemplary embodiments. Therefore, hereinafter, the same blocks as those described above with reference to FIG. 4 are denoted by the same reference numerals, and description thereof will be omitted as appropriate.

  The CCU 100a includes the following functional blocks: a CoMP measurement set determination unit 101, a CSI-RS / muting pattern setting unit 102, a joint scheduler 104 for a plurality of transmission points, a backhaul link (BL) communication unit 105, and Controller 106. Each radio station in the CoMP measurement set communicates with the UE 20a and has the following functional blocks: a BL communication unit 111, a controller 112, a radio transmitter 113, and a radio receiver 114. The UE 20a has the following functional blocks: a radio transmitter 201, a radio receiver 202, a DL signal / interference measurement unit 203, a CQI calculation unit 204, a controller 205, and a request CQI for UE measurement / reporting is determined. Request CQI determination unit 206.

  By using the above functional block, the network 10 can determine the non-zero power / zero power CSI-RS setting, and notifies the UE 20a of the CSI-RS setting together with the interference muting pattern list. The interference muting pattern list shows the relationship between the signal power measured with non-zero power CSI-RS and the interference power measured with zero power CSI-RS. The UE 20a can measure the interference power with signal power and muting based on the set non-zero power CSI-RS and zero power CSI-RS. Thereafter, the UE 20a determines a requested CQI from among a plurality of CQI candidates by using the notified interference muting pattern list, calculates the requested CQI, and feeds back to the network 10 through the UL channel.

2.2) Third Example A third example of the communication method according to the second exemplary embodiment uses signaling of a muting pattern list having a mute cell index. The network 10 determines the CSI-RS setting, and transmits the CSI-RS setting semi-statically to the UE 20a together with the interference muting pattern list of the mute cell index. When the UE 20a receives the list, the UE 20a determines and calculates the requested CQI by using the notified information of interference with muting. The third embodiment will be described below.

  Referring to FIG. 10, in the network 10, the CoMP measurement set determination unit 101 of the CCU 100a determines a CoMP measurement set for the target UE 20 (operation 401). In this example, the CoMP measurement set includes radio station 110 and cooperating radio stations, namely cell 1, cell 2 and cell 3. Next, as shown in FIG. 3, the CSI-RS / muting pattern setting unit 102 performs non-zero power CSI-RS (CSI-RS1) for cell 1, cell 2 and cell 3 over orthogonal resource elements (RE). , CSI-RS2, CSI-RS3) and different power muting patterns (Ma, Mb, Mc, Md) zero power CSI-RS (ZP-CSI-RSa, ZP-CSI-RSb, ZP-CSI-RSc, ZP-CSI-RSd) is set (operation 402). The interference muting pattern list of zero power CSI-RS is shown in FIG. 11A. This lists mute cell IDs.

  Thereafter, the backhaul link communication unit 105 transmits the CSI-RS setting and the interference muting pattern list to the UE 20a via the serving radio station 110 (Operation 403).

  The information of CSI-RS setting is stored as an indicator in the information element of the RRC signal CSI-RS-Config. The information of the interference muting pattern list can also be stored as an indicator in the information element of the RRC signal CSI-RS-Config, or separately as an indicator in the information element of the RRC signal CQI-Report-Config. It can also be stored. Both of these RRC signals are defined in Section 6.3.2 of Non-Patent Document 5. Such an RRC signal is generated by the controller 112 and is semi-statically notified (for example, 120 ms, 240 ms, etc.) to the target UE 20a through the transmitter 113 in the serving radio station 110 (cell 1). The configured non-zero power and zero power CSI-RS (generated by the controller 112 in each cell of the CoMP measurement set) periodically UE 20 with a shorter period (eg, 5 ms, 10 ms, etc.) than the RRC signal. Sent to.

  In the UE 20a, when the radio receiver 202 receives the DL signal from the radio station 110, the signal / interference measuring unit 203 detects the reference signal RS according to the RRC signal, and measures the signal power and the interference power with muting for each cell. (Operation 404). The requested CQI determining unit 206 determines the requested CQI using the notified knowledge of the interference muting pattern (operation 405). Thereafter, CQI calculation section 204 calculates a required CQI using the measured signal power and the interference power with muting (operation 406). Next, a UL signal including the calculated CQI and other CSI is generated and then fed back by the wireless transmitter 201 through an uplink channel such as a PUCCH (Physical Uplink Control Channel) (operation 407). In the radio station 110, the CQI feedback received by the radio receiver 114 is transferred to the CCU 100a through the backhaul link BL1.

  In CCU 100a, when CQI feedback is received, controller 106 controls joint scheduler 104 to perform transmission point (TP) selection, resource allocation, and precoding vector selection for each TP (operation 408). The scheduling result is shared by the radio stations in the CoMP measurement set, that is, cell 1, cell 2, and cell 3, through the backhaul links BL1-BL3. Finally, downlink control information including a part of the dynamic scheduling result is generated in the serving radio station 110 (cell 1) and transmitted by the radio transmitter 113 through a downlink control channel such as PDCCH or ePDCCH. Based on the dynamic scheduling result, downlink data for the UE 20a is generated at the selected TP radio station and transmitted by the radio transmitter 113 through the downlink data channel, ie PDSCH (Physical Downlink Shared Data Channel). (Operation 409). As an example, the control signal is transmitted through the PDCCH or ePDCCH only from the serving point. It is also possible to transmit a control signal from a selected TP or a plurality of selected TPs different from the serving point. In that case, the selected TP may be different from the TP for data transmission.

  When the CoMP measurement set is changed due to the movement of the UE 20a, the CoMP measurement set determination unit 101 updates the CoMP measurement set for the target UE 20a (operation 410). Since the operations including the operations 411 to 412 after the operation 410 are the same as the operations 402 to 409 as described above, description thereof will be omitted.

2.3) Fourth Example A fourth example of the communication method according to the second exemplary embodiment is for signaling a muting pattern list of zero power CSI-RS having a non-muted cell index as shown in FIG. 11B. use. The network 10 determines the CSI-RS configuration and transmits the CSI-RS configuration semi-statically to the UE 20a together with the non-muted cell index interference muting pattern list. When the UE 20a receives the list, the UE 20a determines and calculates the request CQI by using the notified information of the non-muted cell index. According to the fourth embodiment, a list of non-muted cell indexes is transmitted from the network 10 to the UE 20a. This is the main difference between the third embodiment and the fourth embodiment. Since the fourth embodiment is also provided by using a process similar to that of the third embodiment as shown in FIG. 10, the difference will be mainly described below.

  In operation 402 of FIG. 10, the CSI-RS / muting pattern setting unit 102 performs non-zero power CSI-RS (CSI-RS1, CSI-RS2) for cell 1, cell 2, and cell 3 over orthogonal resource elements (RE). , CSI-RS3) and different power muting patterns (Ma, Mb, Mc, Md) zero power CSI-RS (ZP-CSI-RSa, ZP-CSI-RSb, ZP-CSI-RSc, ZP-CSI-) RSd) is set. A list of non-muted interfering cell IDs is shown in FIG. 11B. The list of non-muted cell IDs is notified to the target UE together with the CSI-RS setting (operation 403).

  Such muting pattern list information of zero power CSI-RS with non-mute cell ID is stored in the information element in RRC signal CQI-Report-Config or CSI-RS-Config and is semi-statically transmitted to UE 20a. Sent. In the UE 20a, the required CQI for CoMP scheduling is determined by using the notified muting pattern list, and then calculated by using the measured signal and the interference power with muting. Possible (operations 404-406). Since other operations have already been described with reference to FIG. 10, details thereof will be omitted.

3. Third Exemplary Embodiment For UE mobility and network traffic fluctuations, the network must update the CoMP measurement set. In that case, only a part of the CoMP measurement set needs to be changed each time. For an updated CoMP measurement set, instead of redesigning the CSI-RS configuration and notifying all information related to the requested CQI, the network reuses the available CSI-RS configuration as much as possible, It is preferable that only a control signal for notifying the UE of information reflecting the changed part is transmitted. This simplifies network design and may reduce signaling overhead for repetitive information. For better understanding, some examples are given below.

3.1) Update of CoMP measurement set As shown in FIG. 12, the UE moves from cell 1 through the overlapping area of cell 1 and cell 3 toward cell 4, and with this movement, the CoMP measurement set is updated. Assume that it is updated. In this example, the CoMP measurement set at time t0 consists of cell 1, cell 2 and cell 3, which is updated by UE mobility to consist of cell 1 and cell 3 at time t1, and finally cell 1 at time t2. , Cell 3 and cell 4 are updated. With this UE movement, the corresponding CSI-RS and ZP-CSI-RS settings are updated as shown in FIG. It is assumed that the CCU 100 / 100a, the radio station 110, and the UE 20 / 20a have the same functional configuration as that shown in FIG.

3.2) Fifth Example As shown in FIG. 13, the fifth example of the communication method according to the third exemplary embodiment can set the available CSI-RS settings as much as possible when updating the CoMP measurement set. To re-use, RS pair list signaling for request CQI is used. Referring to the previous CSI-RS configuration for the CoMP measurement set at time t0, the CSI-RS at time t1 is the non-zero power CSI-RS (CSI-RS1, CSI-RS1, CSI-RS 3) is reused, and zero power CSI-RS (ZP-CSI-RSb) with muting pattern Mb is reused to measure interference power other than interference from cell 1 and cell 4. To be set. The above CSI-RS setting is updated at time t1 as shown in FIG. 13, and notified to the UE 20 by using the RRC signal CSI-RS-Config. Thereby, the RS pair list of the request CQI shown in FIG. 13 is determined by the RS pair determination unit 103 (see FIG. 4). This can be transmitted at time t1 using the information element of the RRC signal CQI-Report-Config or CSI-RS-Config. In the UE 20, the requested CQI for each CSI-RS resource listed in FIG. 17 is calculated by the CQI calculation unit 204 (see FIG. 4). Hereinafter, for simplicity, a plurality of CSI-RSs such as CSI-RS1, CSI-RS2, and CSI-RS3 are represented as (CSI-RS1, 2, 3,...).

  At time t2, the CoMP measurement set is updated to cell 1, cell 4, and cell 3. With reference to the previous CSI-RS setting at time t1, CSI-RS at time t2 is set by CSI-RS / muting pattern setting section 102 (see FIG. 4). As shown in FIG. 12, non-zero power CSI-RS (CSI-RS1, 2, 3) are respectively set to measure the signal power of cell 1, cell 4, and cell 3, and muting patterns (Ma, Zero power CSI-RS (ZP-CSI-RSa, b, c, d) having Mb, Mc, Md) is set. The muting patterns (Ma, Mb, Mc) are designed to measure interference power not including interference in the CoMP measurement set other than interference from the cell 3, cell 4, and cell 1, respectively, and Md is the CoMP measurement. Used to exclude all interference from the set. The above CSI-RS configuration is updated at time t2 as shown in FIG. 13, and notified to the UE 20 by using the RRC signal CSI-RS-Config. Thereby, the RS pair list of the request CQI exemplified in FIG. 13 is determined by the RS pair determination unit 103 (see FIG. 4), and at time t2, the RRC signal CQI-Report-Config or CSI-RS-Config It can be sent as an information element. In accordance with the above information, the UE 20 calculates the request CQI for each CSI-RS resource listed in FIG. 17 again by the CQI calculation unit 204 (see FIG. 4).

  Note that, as illustrated in FIG. 13, it is not necessary to repeatedly transmit the RRC signal of the RS pair list for the request CQI at time t0 again at time t1 and time t2 in order to reduce control signal overhead. is there. At time t1, the RS pair of CSI-RS1 / 3 and ZP-CSI-RSb is already included in the RRC signal of the RS pair for the request CQI at time t0. At time t2, the RS pair of request CQI related to (CSI-RS1,2,3) and (ZP-CSI-RSa, b, c, d) is the same as that at time t0. Therefore, there is no need to update the RS pair list at times t1 and t2. Thereby, at time t1, the request CQI related to the set CSI-RS (CSI-RS1, 3) and ZP-CSI-RSb corresponding to the RS pair of CSI-RS1 / 3 and ZP-CSI-RSb. Is calculated and fed back, while at time t2, the request CQI associated with (CSI-RS1,2,3) and (ZP-CSI-RSa, b, c, d) (same as at time t0) ) Will be calculated and fed back.

3.3) Sixth Example As shown in FIG. 14, the sixth example of the communication method according to the third exemplary embodiment can set the available CSI-RS settings as much as possible when updating the CoMP measurement set. In order to reuse, RS pair signaling for unsolicited CQI is used. Instead of transmitting the RS pair for calculating the requested CQI as shown in FIG. 13, a list of RS pairs for the non-requested CQI is determined by the RS pair determining unit 103 (see FIG. 4), and erroneous CQI calculation is performed. Sent to the target UE 20 to avoid. Such RS pair list information is stored in the information element of the RRC signal CQI-Report-Config or CSI-RS-Config, and is transmitted semi-statically to the UE 20. In the UE 20, the CQI for each CSI-RS resource as shown in FIG. 17 is calculated by the CQI calculation unit 204 (see FIG. 4) by using all the combinations of RS pairs. The CQI corresponding to is not calculated or reported.

  As illustrated in FIG. 14, it is not necessary to repeatedly transmit the RRC signal of the RS pair list for the non-requested CQI at time t0 again at times t1 and t2 in order to reduce control signal overhead. At time t1, the CQI associated with the RS pair of CSI-RS1 / 3 and ZP-CSI-RSb used at time t1 is calculated. This is excluded from the RRC signal in the RS pair list for the non-requested CQI at time t0. At time t2, all combinations of (CSI-RS1, 2, 3) and (ZP-CSI-RSa, b, c, d) are supported except for the CQI of the notified RS pair for unrequested CQI at time t0 CQI to be calculated.

3.4) Seventh Example As shown in FIG. 15, the seventh example of the communication method according to the third exemplary embodiment can set the available CSI-RS settings as much as possible when updating the CoMP measurement set. In order to reuse, the interference muting pattern list signaling of the mute cell ID is used. In the present embodiment, similar CSI-RS settings are used at times t0, t1, and t2. In this case, a list of interfering muting patterns with a mute cell index is sent to the target UE 20a to avoid erroneous CQI calculations. Information on such interference muting pattern list is stored in the information element of the RRC signal CQI-Report-Config or CSI-RS-Config, and is transmitted semi-statically to the UE 20a. In the UE 20a, the CQI for each CSI-RS resource as shown in FIG. 17 is determined by the request CQI determination unit 206 and calculated by the CQI calculation unit 204 (see FIG. 9).

  In order to reduce control signal overhead, the RRC signal of the interference muting pattern list of the mute cell index at time t0 does not need to be transmitted again at times t1 and t2, and the updated muting pattern list shown in FIG. Need only be transmitted to the UE 20a at time t2. At time t1, the request CQI related to (CSI-RS1, 3) and ZP-CSI-RSb used at time t1 is calculated with reference to the RRC signal of muting pattern Mb notified at time t0. To be determined. At time t2, (CSI-RS1,2,3) and (ZP-CSI-RSa, b,) used at time t2 according to the RRC signal of the muting pattern at time t0 and the updated muting pattern at time t2. The request CQI related to c, d) is estimated as shown in FIG.

3.5) Eighth Example As shown in FIG. 16, the eighth example of the communication method according to the third exemplary embodiment can set the available CSI-RS settings as much as possible when updating the CoMP measurement set. In order to reuse, the interference muting pattern list signaling with non-mute cell ID is used. By using similar CSI-RS settings at times t0, t1, and t2, a muting pattern list of non-muted cell IDs is sent to the target UE 20a to determine and estimate the requested CQI. Information on such interference muting pattern list is stored in the information element of the RRC signal CQI-Report-Config or CSI-RS-Config, and is transmitted semi-statically to the UE 20a. In the UE 20a, the CQI for each CSI-RS resource as shown in FIG. 17 is determined by the request CQI determination unit 206 and calculated by the CQI calculation unit 204 (see FIG. 9).

  In order to reduce control signal overhead, the RRC signal of the interference muting pattern list of the non-muted cell ID at time t0 does not need to be transmitted again at t1 and t2, and the updated muting pattern list shown in FIG. Only at the time t2 may be notified to the UE 20a. At time t1, the request CQI related to (CSI-RS1, 3) and ZP-CSI-RSb used at time t1 is calculated with reference to the RRC signal of muting pattern Mb notified at time t0. To be determined. At time t2, (CSI-RS1,2,3) and (ZP-CSI-RSa, b,) used at time t2 according to the RRC signal of the muting pattern at time t0 and the updated muting pattern at time t2. The request CQI related to c, d) is determined as shown in FIG.

3.6) Beneficial Effects In the above embodiment as shown in FIGS. 13 to 16, the RRC signal with repeated CSI-RS configuration may also be reduced in order to further reduce the control signal overhead. At time t1, the settings of the non-zero power CSI of (CSI-RS1, 3) and the zero power CSI of (ZP-CSI-RSb) are already notified at time t0. Therefore, at time t1, it is sufficient to notify the UE that the CSI-RS configuration related to cell 2 is deleted, that is, CSI-RS2, ZP-CSI-RSa, c, d are deleted. At time t2, cell 4 is newly introduced into the CoMP measurement set. When comparing the CSI-RS configuration for the CoMP measurement set at times t1 and t2, the information about the RS configuration for cell 1 and cell 3 is not repeated, and the configured non-zero power CSI-RS of CSI-RS2 associated with cell 4 and Only the zero power CSI of (ZP-CSI-RSa, c, d) may be notified to the UE. From an implementation point of view, the UE 20 / 20a needs memory for the previous RS configuration.

  In the above embodiment as shown in FIGS. 6-16, CRS may be used instead of non-zero power CSI-RS for signal power measurement. On the other hand, instead of zero power CSI-RS, PDSCH muting RE or other specific interference measurement RE may be used to measure muted interference with CoMP.

4). Fourth Exemplary Embodiment According to the fourth exemplary embodiment, the functionality of the CCU 100 as shown in FIG. 4 is included as part of each base station (eNB) of the CoMP measurement set. In such inter-eNB CoMP, the UE is connected to a plurality of eNBs, and information is exchanged between the eNBs through an X2 backhaul. Hereinafter, the case of two eNBs will be described as an example.

  As shown in FIG. 18, the base stations eNB1 and eNB2 of the CoMP measurement set have the same block configuration and can communicate with each other through the X2 backhaul interface. eNB1 is provided with a control unit having the function of CCU1, which controls the radio station 110 as a serving cell (cell 1) through the backhaul link BL1. Similarly, eNB2 is provided with a control unit having the function of CCU2, and this controls radio station 120 through backhaul link BL2.

  Each eNB controls the operation of the base station and the operation of notifying the UE 20 of information indicating the interference measurement resource implicitly or explicitly, so that the UE 20 performs CSI-RS and ZP as shown in FIG. -Allow valid CSI-RS pairs to be selected. Since the detailed operation is the same as that of the above-described embodiment and example, detailed description thereof is omitted.

5. Additional Exemplary Embodiments are applicable to mobile communication systems that perform CQI calculation and feedback by measuring signal and interference power using various reference signals. The present invention can be implemented in other specific forms without departing from the technical idea and essential characteristics thereof. Accordingly, the foregoing exemplary embodiments and examples are to be considered in all respects only as illustrative and not restrictive, and the scope of the invention is indicated by the appended claims rather than by the foregoing description. It is. Accordingly, all changes that come within the meaning and range of equivalency of the claims are to be construed as being embraced by the claims. Some or all of the exemplary embodiments described above may be described as described in the appendices, but are not limited thereto.

10 Network 20, 20a User equipment (UE)
100, 100a Central control unit (CCU)
101 CoMP measurement set determination unit 102 CSI-RS / muting pattern setting unit 103 RS pair determination unit 104 Joint scheduler 105 Backhaul link communication unit 106 Controller 110 Radio station (cell)
111 BL communication unit 112 controller 113 wireless transmitter 114 wireless receiver 201 wireless transmitter 202 wireless receiver 203 signal / interference measuring unit 204 CQI calculating unit 205 controller 206 request CQI determining unit

Claims (22)

Resources for CQI (Channel Quality Indicator) value associated is the interference measurement (hereinafter, CSI-IM (Channel State Information - Interference Measurement) that resource.) And first information indicating,
The resources for channel measurement associated with the CQI value (hereinafter, CSI-RS (Channel State Information - Reference Signal) that resource.) And a second information indicating,
A receiver for receiving,
Based on an interference measurement result corresponding to the CSI-IM resource and a channel measurement result corresponding to the CSI-RS resource, a calculation unit that calculates the CQI value;
UE (User Equipment) comprising The receiver receives third information indicative of one or more zero power CSI-RS resources;
The CSI-IM resource overlaps with one of the zero power CSI-RS resources;
The UE according to claim 1. The calculation unit calculates the CQI value based on an interference measurement result corresponding to only the CSI-IM resource and a channel measurement result corresponding only to the CSI-RS resource.
The UE according to claim 1 or 2. The calculation unit calculates the CQI value without using an interference measurement result corresponding to the zero power CSI-RS resource excluding the CSI-IM resource.
The UE according to claim 2 or 3. The first information and the second information are included in an information element of CQI-ReportConfig.
The UE according to any one of claims 1-4. The UE according to claim 1, further comprising: a transmitter that transmits the calculated CQI value to a base station. Resources for CQI (Channel Quality Indicator) value associated is the interference measurement (hereinafter, CSI-IM (Channel State Information - Interference Measurement) that resource.) And first information indicating,
The resources for channel measurement associated with the CQI value (hereinafter, CSI-RS (Channel State Information - Reference Signal) that resource.) And a second information indicating,
A transmitter to transmit,
A receiver that receives the CQI value calculated by a UE (User Equipment) based on an interference measurement result corresponding to the CSI-IM resource and a channel measurement result corresponding to the CSI-RS resource;
A base station comprising: The transmitter transmits third information indicating one or more zero power CSI-RS resources;
The CSI-IM resource overlaps with one of the zero power CSI-RS resources;
The base station according to claim 7. The CQI value is calculated based on an interference measurement result corresponding only to the CSI-IM resource and a channel measurement result corresponding only to the CSI-RS resource.
The base station according to claim 7 or 8. The CQI value is calculated without using an interference measurement result corresponding to the zero power CSI-RS resource excluding the CSI-IM resource.
The base station according to claim 8 or 9. The first information and the second information are included in an information element of CQI-ReportConfig.
The base station according to any one of claims 7 to 10. A communication method of UE (User Equipment),
Resources for CQI (Channel Quality Indicator) value associated is the interference measurement (hereinafter, CSI-IM (Channel State Information - Interference Measurement) that resource.) And first information indicating,
The resources for channel measurement associated with the CQI value (hereinafter, CSI-RS (Channel State Information - Reference Signal) that resource.) And a second information indicating,
Receive
Based on the interference measurement result corresponding to the CSI-IM resource and the channel measurement result corresponding to the CSI-RS resource, the CQI value is calculated.
Communication method. Receiving third information indicative of one or more zero power CSI-RS resources;
The CSI-IM resource overlaps with one of the zero power CSI-RS resources;
The communication method according to claim 12. Based on an interference measurement result corresponding to only the CSI-IM resource and a channel measurement result corresponding only to the CSI-RS resource, the CQI value is calculated.
The communication method according to claim 12 or 13. Calculating the CQI value without using the interference measurement result corresponding to the zero power CSI-RS resource excluding the CSI-IM resource;
The communication method according to claim 13 or 14. The first information and the second information are included in an information element of CQI-ReportConfig.
The communication method according to any one of claims 12 to 15. Transmitting the calculated CQI value to the base station;
The communication method according to any one of claims 12 to 16. A communication method for a base station,
Resources for CQI (Channel Quality Indicator) value associated is the interference measurement (hereinafter, CSI-IM (Channel State Information - Interference Measurement) that resource.) And first information indicating,
The resources for channel measurement associated with the CQI value (hereinafter, CSI-RS (Channel State Information - Reference Signal) that resource.) And a second information indicating,
Send
Receiving the CQI value calculated by UE (User Equipment) based on the interference measurement result corresponding to the CSI-IM resource and the channel measurement result corresponding to the CSI-RS resource;
Communication method. Sending third information indicating one or more zero-power CSI-RS resources;
The CSI-IM resource overlaps with one of the zero power CSI-RS resources;
The communication method according to claim 18. The CQI value is calculated based on an interference measurement result corresponding only to the CSI-IM resource and a channel measurement result corresponding only to the CSI-RS resource.
The communication method according to claim 18 or 19. The CQI value is calculated without using an interference measurement result corresponding to the zero power CSI-RS resource excluding the CSI-IM resource.
The communication method according to claim 19 or 20. The first information and the second information are included in an information element of CQI-ReportConfig.
The communication method according to any one of claims 18-21.

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