JP2012010221A - Terminal device, base station device, communication system, and communication method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a terminal device, a base station device, a communication system, and a communication method capable of efficiently specifying and applying a proper MCS, spatial multiplex number, and precoder in a communication system capable of carrier aggregation.SOLUTION: In a communication system which can aggregate a plurality of component carriers and performs communication between a base station device and a terminal device, the base station device sets a feedback cycle for periodically reporting a reception quality indicator specifying a preferable transmission rate in a frequency bandwidth for each component carrier such that the feedback cycles for the respective component carriers are the same with one another, and notifies the terminal device of control information to be notified by the base station device using the feedback cycle. The terminal device periodically reports to the base station device the reception quality indicator specifying the preferable transmission rate in the frequency bandwidth for each component carrier based on the control information notified by the base station device.

Description

  The present invention relates to a terminal device, a base station device, a communication system, and a communication method.

  3CDMA (Third Generation Partnership Project) WCDMA (Wideband Code Divide Multiple Access), LTE (Long Term Evolution), LTE-A (LTE-Advanced Advanced) and LTE-A (LTE-Advanced By adopting a cellular configuration in which a plurality of areas covered by a base station device (base station, transmission station, downlink transmission device, uplink reception device, eNodeB) or a transmission station according to the base station are arranged in a cell (Cell) shape, The communication area can be expanded. In addition, by using different frequencies between adjacent cells or sectors, a terminal device (mobile station, receiving station, uplink transmitter, downlink receiver, mobile terminal, cell edge (cell edge) region or sector edge region, Even in UE (User Equipment), communication can be performed without receiving interference of transmission signals from a plurality of base station apparatuses, but there is a problem that frequency utilization efficiency is low. On the other hand, frequency utilization efficiency can be improved by using the same frequency between adjacent cells or sectors, but it is necessary to take measures against interference with terminal devices in the cell edge region.

  In addition, depending on the transmission path status between the base station apparatus and the terminal apparatus, modulation scheme and coding rate (MCS), spatial multiplexing number (layer number, rank), precoder (precoder), etc. By performing adaptive control, more efficient data transmission can be realized. Non-Patent Document 1 shows a method of performing these controls.

  FIG. 20 is a diagram illustrating a base station apparatus 2001 and a terminal apparatus 2002 that perform adaptive control using feedback information in the conventional technique. In the conventional technique, when adaptively controlling the MCS, the number of spatial multiplexing, and the precoder for the downlink transmission signal 2003 to be transmitted, the terminal apparatus 2002 transmits the downlink transmission signal 2003 transmitted from the base station apparatus 2001 to the downlink transmission signal 2003. With reference to the included downlink reference signal (RS), CQI (Channel Quality Indicator), RI (Rank Indicator), and PMI (Precoding Matrix Indicator) are respectively calculated, and uplink channel 200 is used as feedback information. To the base station apparatus 2001. Here, RI is an index indicating a spatial multiplexing number (a rank index specifying a suitable spatial multiplexing number), PMI is an index indicating a preferable precoding matrix (precoder information specifying a preferable precoder), and CQI Is an index indicating a transmission rate for maintaining a predetermined communication quality (a reception quality index for designating a suitable transmission rate). Non-Patent Document 1 describes a feedback mode for periodically reporting the feedback information.

  On the other hand, in order to efficiently realize wideband transmission, a plurality of continuous and / or discontinuous frequency bands (hereinafter referred to as “component carrier (CC: Component Carrier)” or “carrier component (CC: Carrier Component)”). ) Are used in combination and operated as one wide frequency band (referred to as carrier aggregation). Furthermore, the frequency band used for downlink communication and the frequency band used for uplink communication have different frequency bandwidths (asymmetric frequency band aggregation), so that the base station apparatus 2001 and the terminal apparatus 2002 can communicate using a wide frequency band more flexibly. Such a communication method is shown in Non-Patent Document 2.

  FIG. 21 is a diagram for explaining a mobile communication system in which frequency bands are aggregated in a conventional technique. In particular, FIG. 21 shows a mobile communication system in which asymmetric frequency bands are aggregated as an example. As shown in FIG. 21, the base station apparatus 2001 and the terminal apparatus 2002 use a plurality of component carriers that are continuous and / or discontinuous frequency bands in a composite manner, thereby forming a wideband composed of a plurality of component carriers. Communication can be performed in a wide frequency band.

  In FIG. 21, as an example, five frequency bands (hereinafter also referred to as DL system band and DL system bandwidth) used for downlink communication having a bandwidth of 100 MHz have five bandwidths of 20 MHz. It shows that it is configured by downlink component carriers (DCC1: Downlink Component Carrier1, DCC2, DCC3, DCC4, DCC5). Further, as an example, two uplinks having a frequency band (hereinafter also referred to as UL system band or UL system bandwidth) used for uplink communication having a bandwidth of 40 MHz have a bandwidth of 20 MHz. It shows that it is composed of component carriers (UCC1: Uplink Component Carrier1, UCC2).

  In FIG. 21, each downlink component carrier has a downlink physical such as a physical downlink control channel (hereinafter referred to as PDCCH: Physical Downlink Control Channel) and a physical downlink shared channel (hereinafter referred to as PDSCH: Physical Downlink Shared Channel). A channel is placed. The base station apparatus 2001 allocates downlink control information (DCI: Downlink Control Information) for transmitting the PDSCH to the terminal apparatus 2002 using the PDCCH, and transmits the PDSCH to the terminal apparatus 2002. That is, in FIG. 21, the base station apparatus 2001 can transmit up to five PDSCHs (which may be downlink transport blocks) to the terminal apparatus 2002 in the same subframe.

  Each uplink component carrier has an uplink physical channel such as a physical uplink control channel (hereinafter PUCCH: Physical Uplink Control Channel) and a physical uplink shared channel (hereinafter PUSCH: Physical Uplink Shared Channel). Be placed. The terminal device 2002 transmits uplink control information (UCI: Uplink Control Information) to the base station device 2001 using PUCCH and / or PUSCH. In FIG. 21, the terminal apparatus 2002 can transmit up to five PUSCHs (or uplink transport blocks may be used) to the base station apparatus 2001 in the same subframe.

3rd Generation Partnership Project; Technical Specification Group Radio Access Network; Evolved Universal Terrestrial Radio Access (E-UTRA); Physical layer procedures (Release 8), 12 May 2008, 3GPP TS 36.213 V8.8.0 (2009-9 ). “Carrier aggregation in LTE-Advanced”, 3GPP TSG RAN WG1 Meeting # 53bis, R1-084464, June 30-Jully 4, 2008.

  However, since the conventional communication method can only report feedback information for one component carrier, it is difficult to specify and apply an appropriate MCS, spatial multiplexing number, and precoder in a communication system that can aggregate frequency bands. It was a factor that hindered efficiency improvements.

  The present invention has been made in view of the above problems, and an object thereof is to efficiently designate and apply an appropriate MCS, spatial multiplexing number, and precoder in a communication system capable of frequency band aggregation. A terminal device, a base station device, a communication system, and a communication method are provided.

  (1) The present invention has been made to solve the above-described problems, and a terminal device according to an aspect of the present invention is a terminal device that communicates with a base station device in a communication system capable of aggregating a plurality of component carriers. A feedback period for periodically reporting a reception quality indicator designating a suitable transmission rate in the frequency bandwidth of each component carrier is set to be the same for each of the component carriers, and the feedback period is set to And reporting to the base station apparatus.

  (2) Moreover, the terminal device according to an aspect of the present invention is the terminal device described above, wherein the feedback cycle is set based on a frequency bandwidth in any of the component carriers.

  (3) The terminal device according to an aspect of the present invention is the terminal device described above, wherein the feedback period is set based on the frequency bandwidth in the component carrier having the largest frequency bandwidth. And

  (4) Moreover, the terminal device according to an aspect of the present invention is the terminal device described above, wherein the feedback period is set based on the frequency bandwidth in the component carrier having the smallest frequency bandwidth. And

  (5) Moreover, the terminal device according to an aspect of the present invention is the above-described terminal device, wherein the feedback period is based on the frequency bandwidth in a primary component carrier designated by the base station device from among the component carriers. It is characterized by being set.

  (6) Moreover, the terminal device by 1 aspect of this invention is said terminal device, Comprising: The said feedback period is set based on the frequency bandwidth in all the said component carriers, It is characterized by the above-mentioned.

  (7) A terminal device according to an aspect of the present invention is the terminal device described above, and a reception quality indicator that specifies a suitable transmission rate in a frequency bandwidth for each component carrier is cyclic for each component carrier. It is characterized by being reported to.

  (8) Moreover, the terminal device according to an aspect of the present invention is the terminal device described above, and a reception quality index that specifies a suitable transmission rate in a frequency bandwidth for each component carrier is the same for all of the component carriers. It is characterized by being reported cyclically by a feedback period.

  (9) A terminal device according to an aspect of the present invention is the terminal device described above, and a reception quality indicator that specifies a suitable transmission rate in a frequency bandwidth for each component carrier is unique to each component carrier. It is characterized by being reported cyclically by a feedback period.

  (10) A base station apparatus according to an aspect of the present invention is a base station apparatus that communicates with a terminal apparatus in a communication system capable of aggregating a plurality of component carriers, and is suitable for a frequency bandwidth for each component carrier. Control information for setting a feedback cycle for periodically reporting a reception quality index specifying a transmission rate to be the same for each of the component carriers and causing the base station apparatus to report using the feedback cycle Is notified to the terminal device.

  (11) A base station apparatus according to an aspect of the present invention is the base station apparatus described above, wherein the feedback period is set based on a frequency bandwidth in one of the component carriers. .

  (12) A base station apparatus according to an aspect of the present invention is the base station apparatus described above, wherein the feedback period is set based on a frequency bandwidth in all of the component carriers.

  (13) A communication system according to an aspect of the present invention is a communication system that performs communication between a base station apparatus and a terminal apparatus that can aggregate a plurality of component carriers, and the base station apparatus includes the component carrier A feedback period for periodically reporting a reception quality index specifying a suitable transmission rate in each frequency bandwidth is set to be the same for each of the component carriers, and the base station is configured using the feedback period. The terminal device is notified of control information for causing a device to report, and the terminal device is configured to transmit a suitable transmission rate in the frequency bandwidth for each component carrier based on the control information notified from the base station device. Is periodically reported to the base station apparatus.

  (14) A communication system according to an aspect of the present invention is the communication system described above, wherein the feedback period is set based on a frequency bandwidth in one of the component carriers.

  (15) A communication system according to an aspect of the present invention is the communication system described above, wherein the feedback period is set based on a frequency bandwidth in all of the component carriers.

  (16) A communication method according to an aspect of the present invention is a communication method for a terminal apparatus that communicates with a base station apparatus in a communication system capable of aggregating a plurality of component carriers, in a frequency bandwidth for each component carrier. Setting a feedback period for periodically reporting a reception quality indicator specifying a suitable transmission rate to be the same for each of the component carriers, and reporting to the base station apparatus using the feedback period. It is characterized by having.

  (17) A communication method according to an aspect of the present invention is a communication method of a base station device that communicates with a terminal device in a communication system capable of aggregating a plurality of component carriers, in a frequency bandwidth for each component carrier. A feedback period for periodically reporting a reception quality index specifying a suitable transmission rate is set to be the same for each of the component carriers, and the base station apparatus is used to report using the feedback period The method includes a step of notifying the terminal device of control information.

  According to the present invention, it is possible to efficiently designate and apply an appropriate MCS, spatial multiplexing number, and precoder.

It is a schematic block diagram which shows the structure of the communication system in the 1st Embodiment of this invention. It is a figure which shows an example of a radio frame structure of the downlink which concerns on this embodiment. It is a figure which shows an example of the radio frame structure of the uplink which concerns on this embodiment. It is a figure which shows an example of the subband structure which concerns on this embodiment. It is a figure which shows an example of the frequency band aggregation in the downlink which concerns on this embodiment. It is a figure which shows an example of the report procedure of the feedback information which concerns on this embodiment. It is a figure which shows an example of the feedback period which concerns on this embodiment. It is a figure which shows an example of the report procedure of the feedback information which concerns on this embodiment. It is a figure which shows an example of the report procedure of the feedback information which concerns on this embodiment. It is a figure which shows an example of the report procedure of the feedback information which concerns on this embodiment. It is an example of the code book of the partial precoder information which concerns on this embodiment. It is an example of the code book which concerns on this embodiment. It is a conceptual diagram of the precoding process which concerns on this embodiment. It is a figure which shows an example of RS for measuring PI. It is a figure which shows an example of the report procedure of the feedback information which concerns on this embodiment. It is a figure which shows an example of the feedback period which concerns on this embodiment. It is a figure which shows an example of the report procedure of the feedback information which concerns on this embodiment. It is the schematic which shows an example of a structure of the base station apparatus which concerns on this embodiment. It is the schematic which shows an example of a structure of the terminal device (reception apparatus) which concerns on this embodiment. It is a figure which shows the base station and terminal device which perform adaptive control using the feedback information in a prior art. It is a figure explaining the mobile communication system by which the frequency band aggregation in the prior art was carried out.

(First embodiment)
Hereinafter, a first embodiment of the present invention will be described with reference to the drawings.

  FIG. 1 is a schematic configuration diagram showing a configuration of a communication system according to the first embodiment of the present invention. The communication system in FIG. 1 assumes an LTE-A system, and a base station apparatus (base station, transmission station, downlink transmission apparatus, uplink reception apparatus, eNodeB) 101 and a terminal apparatus (mobile station, A receiving station, an uplink transmitting device, a downlink receiving device, a mobile terminal, and a UE (User Equipment) 102. 1 is a communication system in which frequency bands are aggregated by a plurality of DCCs. When adaptively controlling the MCS, the spatial multiplexing number, and the precoder for the downlink transmission signal 103 to be transmitted, the terminal apparatus transmits a downlink reference signal (included in the downlink transmission signal 103 transmitted from the base station apparatus 101). RS: Reference Signal (RS) is referenced for each DCC, and information on a suitable MCS, information on a suitable spatial multiplexing number, and a plurality of partial precoder information specifying a preferred Precoder are calculated, and feedback for each DCC Generate information. Each terminal apparatus periodically reports to the base station apparatus 101 via the uplink channel 104. Here, a case where partial precoder information 1 (PI1) and partial precoder information 2 (PI2) are reported as partial precoder information PI (Precoder Information) will be described. As a suitable precoder, for example, a method of calculating a precoder that increases the downlink received signal power in consideration of the downlink propagation path can be used. Details of the partial precoder information PI will be described later.

  FIG. 2 shows an example of a downlink radio frame configuration according to the present embodiment. An OFDM (Orthogonal Frequency Division Multiplex) access scheme is used for the downlink. In the downlink, a physical downlink control channel (PDCCH), a physical downlink shared channel (PDSCH), and the like are allocated. Also, a downlink reference signal (RS) is multiplexed on a part of PDSCH. The downlink radio frame is composed of a downlink resource block (RB) pair. This downlink RB pair is a unit such as downlink radio resource allocation, and is based on a predetermined frequency band (RB bandwidth) and time band (2 slots = 1 subframe). Become. One downlink RB pair is composed of two downlink RBs (RB bandwidth × slot) that are continuous in the time domain. One downlink RB is composed of 12 subcarriers in the frequency domain, and is composed of 7 OFDM symbols in the time domain. The physical downlink control channel is a physical channel through which downlink control information such as a terminal device identifier, downlink shared channel scheduling information, uplink shared channel scheduling information, modulation scheme, coding rate, and retransmission parameter is transmitted. .

  FIG. 3 shows an example of an uplink radio frame configuration according to the present embodiment. For the uplink, an SC-FDMA (Single Carrier-Frequency Division Multiple Access) system is used. In the uplink, a physical uplink shared channel (PUSCH), a physical uplink control channel (PUCCH), and the like are allocated. Further, an uplink reference signal is assigned to a part of PUSCH or PUCCH. The uplink radio frame is composed of uplink RB pairs. This uplink RB pair is a unit for allocation of uplink radio resources and the like, and is based on a predetermined frequency band (RB bandwidth) and time band (2 slots = 1 subframe). Become. One uplink RB pair is composed of two uplink RBs (RB bandwidth × slot) that are continuous in the time domain. One uplink RB is composed of 12 subcarriers in the frequency domain, and is composed of 7 SC-FDMA symbols in the time domain.

  FIG. 4 shows an example of a subband configuration according to the present embodiment. A plurality of adjacent RBs are combined to form a subband, and a plurality of subbands are combined to form a BP (Bandwidth Part, partial bandwidth, partial frequency bandwidth). In the configuration diagram shown in FIG. 4, S subbands and J BPs are arranged in the downlink bandwidth.

FIG. 5 shows an example of frequency band aggregation in the downlink according to the present embodiment. Hereinafter, BP number is _{J 1} DCC1 and BP numbers illustrate the case where the frequency band aggregation by two DCC including DCC2 is _{J 2.} The terminal apparatus 102 periodically reports (feeds back) feedback information in the DCC 1 and DCC 2 to the base station apparatus 101. Here, the terminal apparatus 102 reports RI, PI1, PI2, W-CQI (Wideband-CQI), and S-CQI (Subband-CQI) as feedback information. At this time, RI, PI1, PI2, and W-CQI are transmitted at the same time, but the information transmitted at the same time may be independent feedback information, or an index indicating the information by joint coding is used as feedback information. It is good. W-CQI is CQI in the downlink bandwidth. Since the S-CQI is a CQI representing each BP, it is reported for each BP. For example, the S-CQI is a difference CQI with respect to the W-CQI in each subband, and the terminal apparatus 102 selects a subband that is a suitable CQI in each BP. Therefore, the number of times (resources) for reporting the S-CQI is determined by the number of BPs in the DCC. Here, in this embodiment, the PUCCH resource (feedback resource) for the terminal apparatus 102 to report feedback information is set to the same size in all the DCCs to be reported. That is, even when the number of BPs differs between the DCCs to be reported, the feedback resource for each DCC is made the same size.

FIG. 6 shows an example of a procedure (report) for reporting feedback information according to the present embodiment. In the reporting procedure in FIG. 6, a case will be described in which the number of feedback resources in each of all DCCs is the largest number of feedback resources in the DCC to be reported. That is, the number of feedback resources in each of all the DCCs is the number of feedback resources in the DCC that maximizes the downlink bandwidth. Moreover, BP number _{J 1} in DCC1 is 4, a case BP number _{J 2} in DCC2 is 3. That is, the number of feedback resources in each DCC is based on the case where the number of BPs is 4.

First, the base station apparatus 101 sets a feedback parameter in the terminal apparatus 102 via RRC (Radio Resource Control) signaling, and instructs periodic feedback (step S601). The terminal apparatus 102 instructed to perform periodic feedback first reports feedback information in the DCC 1. The terminal apparatus 102 periodically reports the RI and PI1 (step S602) in the DCC1 and the PI2 and W-CQI (step S603) in the DCC1 to the base station apparatus 101 according to the set feedback parameters. Further, the terminal apparatus 102 periodically reports S-CQI in DCC 1 (steps S604 to S607). Specifically, the terminal apparatus 102 performs S-CQI1 representing the first BP in DCC1 (step S604), S-CQI2 representing the second BP in DCC1 (step S605), and the third BP in DCC1. S-CQI3 (step S606) representing DC and S-CQI4 (step S607) representing the fourth BP in DCC1 are reported. The S-CQI report shown in steps S604 to S607 is periodically performed K times (cycles) between the W-CQI report in step S603 and the W-CQI report in step S609 described later. Is called. That is, the S-CQI report in DCC ₁ is periodically performed J ₁ · K (= H ₁ −1) times. However, _{H 1} is a predetermined _value, represented by _{H 1 = J 1 · K +} 1. In the example shown in FIG. 6, the case of K = 1 is shown.

Furthermore, the terminal apparatus 102 reports feedback information in DCC2. The terminal apparatus 102 periodically reports the RI and PI1 in the DCC2 (step S608) and the PI2 and W-CQI (step S609) in the DCC2 to the base station apparatus 101 according to the set feedback parameters. Further, the terminal apparatus 102 periodically reports the S-CQI in the DCC 2 using a feedback resource having the same size as the feedback resource for reporting the S-CQI in the DCC 1 (steps S610 to S613). Specifically, the terminal apparatus 102 performs S-CQI1 representing the first BP in DCC2 (step S610), S-CQI2 representing the second BP in DCC2 (step S611), and the third BP in DCC2. S-CQI3 (step S612) representing each is reported. At the timing of reporting the fourth S-CQI shown in step S613, the terminal apparatus 102 transmits nothing or transmits other information. The S-CQI report shown in steps S610 to S613 is periodically performed by repeating K times (cycles) between the W-CQI report in step S609 and the W-CQI report in step S603 described later. Is called. That is, the S-CQI report in the DCC _{2 is} periodically performed J ₂ · K (= H ₂ −1) times using feedback resources for J ₁ · K (= H ₁ −1) times. However, _{H 2} is a predetermined _value, represented by _{H 2 = J 2 · K +} 1. In the example shown in FIG. 6, the case of K = 1 is shown. Thereafter, the reports or processes shown in steps S602 to S613 are repeated periodically.

  Here, the interval of the vertical axis in FIG. 6 does not represent the magnitude of time, and the reporting of each feedback information is not limited to the order shown in FIG. Specifically, the feedback period can be set independently for RI or PI1 and other feedback information. That is, when the periods of W-CQI, PI2, or S-CQI reporting subframes and RI or PI1 reporting subframes are set independently, the reporting order may be changed. Further, a subframe that reports W-CQI, PI2, or S-CQI and a subframe that reports RI or PI1 may be the same subframe. In this case, RI or PI1 is reported without reporting W-CQI, PI2, or S-CQI. Further, it is possible to set so that RI or PI1 or PI2 is not fed back by RRC signaling in step 601. In that case, the terminal apparatus 102 reports only CQI.

  As described above, the number of subframes (number of PUCCHs) allocated to report feedback information related to the narrow band in each DCC is the number of subframes (number of PUCCHs) allocated to report feedback information about the narrow band. Is set to a value at DCC having the largest number. In other words, the W-CQI reporting period in each DCC is set to a value in the DCC having the largest W-CQI reporting period.

At this time, in the DCC in which the set feedback resource is larger than the number of resources required to report the S-CQI, the reporting procedure described in FIG. -Report CQI. That is, DCC2 reports J ₂ S-CQIs using a part of the resources for J ₁ times. Such feedback is repeated K times. In DCC2, J ₂ S-CQIs may be repeatedly reported K times using J ₁ · K resources. Alternatively, in DCC2, H ₂ -1 S-CQIs are reported using a part of the resources for H ₁ -1 times. Although K = 1 in the above description, the present invention is not limited to this. A common K (K is an integer of 1 or more) may be used for each DCC, or an individual K (for example, K ₁ for DCC1, K _{2 for} DCC2, etc.) may be used for each DCC. In this case, H ₁ -1 (= J ₁ · K ₁ ) and H ₂ -1 (= J ₂ · K ₂ ) are compared, and the larger value is used to determine the W-CQI reporting period. do it.

  By using the feedback information reporting procedure as shown in FIG. 6, the feedback cycle (the W-CQI reporting cycle) can be made the same for all of the DCCs to report, so that efficient feedback can be realized. In addition, the method as shown in FIG. 6 can reduce the overhead of control information for performing feedback while facilitating consistency as compared with the case where feedback is performed independently for each DCC. Furthermore, a constant feedback period can be set in one terminal, and resource contention between terminals is less likely to occur, and the degree of scheduling freedom is improved.

FIG. 7 is a diagram illustrating an example of a feedback cycle according to the present embodiment. FIG. 7 illustrates a feedback cycle in the feedback information reporting procedure described in FIG. Further, the horizontal axis of FIG. 7 indicates time. W-CQI and PI2 in each DCC are cyclically reported in subframes shifted by N _{OFFSET and CQI} from the reference subframe in the period of H ′ · NP subframe. In addition, RI and PI1 in each DCC have a period of H ′ · N _P · M _RI that is M _RI times the period of W-CQI and W-PMI, and N _{OFFSET and CQI} + N _OFFSET from the reference subframe _{, And} sub-frames shifted by _RI , ie, W-CQI and W-PMI, are further reported cyclically in sub-frames further shifted by N _{OFFSET, RI} . Here, in the example illustrated in FIG. 7, the case where the feedback resource in all DCCs is the largest feedback resource in the DCC to be reported has been described, so H ′ is H ₁ . Furthermore, S-CQI is reported in a reporting cycle of the W-CQI H '· _N period _P subframe. That is, the S-CQI in each DCC is reported in a period of H ₁ · N _P (= (J ₁ · K + 1) · N _P ) subframes. S-CQI in DCC1 _is the H 1 · _N period _P subframe _is reported _{J 1 · K (= H 1} -1) times. Further, S-CQI in _DCC2, during a H 1 · _{N P subframe, J 2 · K (= H} 2 -1) times reported although, as described above with reference to FIG. 6, K times repeatedly reported in each iteration when, (J 1 _{-J 2)} once or you do not send anything to transmit other information. Here, each of the S-CQIs reported J ₁ · K times and J ₂ · K times is a CQI representing BP. The CQI in J ₁ and J ₂ BPs is reported sequentially from the CQI in the low frequency BP for each DCC, and J ₁ and J ₂ reports are made to cover the downlink bandwidth. Moreover, by repeating each K cycle _{J 1} once and _{J 2} times _{Report, H '· N P J 1} · K times during the sub-frame and _{J 2} · K times reporting is performed. Alternatively, S-CQI in DCC2 _among the _H 1 -1 _subframe, the first _H 2 -1 subframes of _H 2 -1 subframes (e.g. _H 1 -1 subframe ) And other information is transmitted to send nothing in the remaining (H ₁ -H ₂ ) subframes. As described above, the feedback information in the m DCC is performed in a cycle of _{m · H '· N P ·} M RI.

Referring also to FIG. 7 from another viewpoint, W-CQI in each DCC is reported in a cycle of m · H '· _{N P.} Furthermore, S-CQI in each DCC is, _{J x} · K times in a cycle of _{N P} after reporting the W-CQI in each DCC (X is the number of DCC) are reported.

FIG. 8 shows an example of a feedback information reporting procedure according to the present embodiment. In the reporting procedure in FIG. 8, a case will be described in which the number of feedback resources in each of all DCCs is the largest number of feedback resources among the DCCs to be reported. That is, the number of feedback resources in each of all the DCCs is the number of feedback resources in the DCC that maximizes the downlink bandwidth. Moreover, BP number _{J 1} in DCC1 is 4, a case BP number _{J 2} in DCC2 is 3. That is, the feedback resource in each DCC has a size based on the case where the number of BPs is 4.

First, the base station apparatus 101 sets a feedback parameter in the terminal apparatus 102 via RRC (Radio Resource Control) signaling, and instructs periodic feedback (step S801). The terminal apparatus 102 instructed to perform periodic feedback first reports feedback information in the DCC 1. The terminal apparatus 102 periodically reports the RI and PI1 (step S802) in the DCC1 and the PI2 and W-CQI (step S803) in the DCC1 to the base station apparatus 101 according to the set feedback parameters. Furthermore, the terminal apparatus 102 periodically reports S-CQI in DCC1 (steps S804 to S807). Specifically, the terminal apparatus 102 performs S-CQI1 representing the first BP in DCC1 (step S804), S-CQI2 representing the second BP in DCC1 (step S805), and the third BP in DCC1. S-CQI3 (step S806) representing DC and S-CQI4 (step S807) representing the fourth BP in DCC1 are reported. The S-CQI report shown in steps S804 to S807 is periodically performed K times (cycles) between the W-CQI report in step S803 and the W-CQI report in step S809 described later. Is called. That is, the S-CQI report in DCC ₁ is periodically performed J ₁ · K (= H ₁ −1) times. In the example shown in FIG. 8, the case of K = 1 is shown.

Furthermore, the terminal apparatus 102 reports feedback information in DCC2. The terminal apparatus 102 periodically reports the RI and PI1 in DCC2 (step S808) and the PI2 and W-CQI (step S809) in DCC2 to the base station apparatus 101 according to the set feedback parameters. Further, the terminal apparatus 102 periodically reports the S-CQI in the DCC 2 using a feedback resource having the same size as the feedback resource reporting the S-CQI in the DCC 1 (steps S810 to S813). Specifically, the terminal apparatus 102 performs S-CQI1 representing the first BP in DCC2 (step S810), S-CQI2 representing the second BP in DCC2 (step S811), and the third BP in DCC2. S-CQI3 (step S812) representing each is reported. At the timing of reporting the fourth S-CQI shown in step S813, the terminal apparatus 102 reports the S-CQI in the same BP as the S-CQI1 reported in step S810. The S-CQI report shown in steps S810 to S813 is periodically performed by repeating K times (cycles) between the W-CQI report in step S809 and the W-CQI report in step S803. That is, the S-CQI report in the DCC _{2 is} periodically performed J ₂ · K (= H ₂ −1) times using feedback resources for J ₁ · K (= H ₁ −1) times. In the example shown in FIG. 8, the case of K = 1 is shown. Alternatively, in DCC2, by using a part of H ₁ −1 resources (for example, the first H ₂ −1 subframes of H ₁ −1 subframes), H ₂ −1 S− Report CQI. Further, in the remaining (H ₁ -H ₂ ) subframes, the S-CQI in the same BP as the previously reported S-CQI is transmitted. For example, in DCC2, S-CQIs in J ₂ BPs are sequentially reported from the lowest frequency, and this is repeated for floor ((H ₁ -1) / J ₂ ) cycles. Further, in the remaining (J ₁ · K−J ₂ · floor ((H ₁ −1) / J ₂ )) subframes, (J ₁ · K−J ₂ · floor ((H ₁ -1) / J ₂ )) S-CQIs in BPs are reported sequentially. Here, floor () is a floor function. Thereafter, the reports shown in steps S802 to S813 are repeated periodically.

  Here, the interval of the vertical axis in FIG. 8 does not represent the size of time, and the report of each feedback information is not limited to the order shown in FIG. Specifically, the feedback period can be set independently for RI or PI1 and other feedback information. That is, when the periods of W-CQI, PI2, or S-CQI reporting subframes and RI or PI1 reporting subframes are set independently, the reporting order may be changed. Further, a subframe that reports W-CQI, PI2, or S-CQI and a subframe that reports RI or PI1 may be the same subframe. In this case, RI or PI1 is reported without reporting W-CQI, PI2, or S-CQI. Further, it is possible to set so that RI or PI1 or PI2 is not fed back by RRC signaling in step 601. In that case, the terminal apparatus 102 reports only CQI.

As described above, in the DCC in which the set number of feedback resources is larger than the number of resources necessary for reporting the S-CQI, the reporting procedure illustrated in FIG. 8 is repeated using the set feedback resources. Report S-CQI. That is, in DCC2, using _{J 1} dose of resources, and report repeatedly _{J 2} pieces of S-CQI. Such feedback is repeated K times. In DCC2, J ₂ S-CQIs may be repeatedly reported using J ₁ · K resources.

  By using the feedback information reporting procedure as shown in FIG. 8, the feedback cycle (the W-CQI reporting cycle) is the same in all the reporting DCCs, or the S-CQI reporting is performed in all the reporting DCCs. Since the same number of subframes can be used, the efficient feedback can be realized. In addition, the method as shown in FIG. 8 can reduce the overhead of control information for performing feedback while facilitating consistency as compared with the case where feedback is performed independently for each DCC. Moreover, since all the set feedback resources can be used, effective adaptive control can be realized.

FIG. 9 shows an example of a feedback information reporting procedure according to the present embodiment. In the reporting procedure in FIG. 9, a case will be described in which the number of feedback resources in each of all the DCCs is the smallest number of feedback resources among the DCCs to be reported. That is, the number of feedback resources in each of all DCCs is the number of feedback resources in the DCC that minimizes the downlink bandwidth. Moreover, BP number _{J 1} in DCC1 is 4, a case BP number _{J 2} in DCC2 is 3. That is, the feedback resource in each DCC has a size based on the case where the number of BPs is 3.

First, the base station apparatus 101 sets a feedback parameter in the terminal apparatus 102 via RRC (Radio Resource Control) signaling, and instructs periodic feedback (step S901). The terminal apparatus 102 instructed to perform periodic feedback first reports feedback information in the DCC 1. The terminal apparatus 102 periodically reports the RI and PI1 in the DCC1 (step S902) and the PI2 and W-CQI (step S903) in the DCC1 to the base station apparatus 101 according to the set feedback parameters. Further, the terminal apparatus 102 periodically reports the S-CQI in the DCC 1 using a feedback resource having the same size as the feedback resource for reporting the S-CQI in the DCC 2 (steps S904 to S906). Specifically, the terminal apparatus 102 performs S-CQI1 representing the first BP in DCC1 (step S904), S-CQI2 representing the second BP in DCC1 (step S905), and the third BP in DCC1. S-CQI3 (step S906) representing each is reported. At this time, the terminal apparatus 102 omits the report of the S-CQI 4 representing the fourth BP in the DCC 1. The S-CQI report shown in steps S904 to S906 is periodically performed K times (cycles) between the W-CQI report in step S903 and the W-CQI report in step S908 described later. Is called. That is, the report of S-CQI in DCC 1 is periodically performed J ₂ · K (= H ₂ −1) times. Alternatively, in _DCC1, using _H 2 -1 times of _resources, reporting -1 _H 2 of _H 1 -1 of S-CQI. In the example shown in FIG. 9, the case of K = 1 is shown.

Furthermore, the terminal apparatus 102 reports feedback information in DCC2. The terminal apparatus 102 periodically reports RI and PI1 in DCC2 (step S907) and PI2 and W-CQI (step S908) in DCC2 to the base station apparatus 101 according to the set feedback parameters. Further, the terminal apparatus 102 periodically reports S-CQI in DCC2 (steps S909 to S911). Specifically, the terminal apparatus 102 performs S-CQI1 representing the first BP in DCC2 (step S909), S-CQI2 representing the second BP in DCC2 (step S910), and the third BP in DCC2. S-CQI3 (step S911) representing each is reported. The S-CQI report shown in steps S909 to S911 is periodically performed by repeating K times (cycles) between the W-CQI report in step S908 and the W-CQI report in step S903. In other words, it reports S-CQI in DCC2 _uses the feedback resource of the _{J 2 · K (= H 2} -1) _{times, J 2 · K (= H 2} -1) times are performed periodically. In the example shown in FIG. 9, the case of K = 1 is shown. Alternatively, in _{DCC1, H} 2 using the -1 dose of _{resources, H} 1 _H 2 -1 of -1 S-CQI (e.g. _H 1 -1 first _H of the S-CQI ₂ - 1 S-CQI) is reported. For example, in DCC1, S-CQIs in J ₁ BPs are reported in order from the lowest frequency, and this is repeated on the floor ((H ₂ −1) / J ₁ ) cycle. Further, in the remaining (J ₂ · K−J ₁ · floor ((H ₂ −1) / J ₁ )) subframes, (J ₂ · K−J ₁ · floor ((H ₂ -1) _{/ J} 1)) successively report S-CQI in number of BP. Thereafter, the reports shown in steps S902 to S911 are repeated periodically.

  Here, the interval of the vertical axis in FIG. 9 does not represent the size of time, and the reporting of each feedback information is not limited to the order shown in FIG. Specifically, the feedback period can be set independently for RI or PI1 and other feedback information. That is, when the periods of W-CQI, PI2, or S-CQI reporting subframes and RI or PI1 reporting subframes are set independently, the reporting order may be changed. Further, a subframe that reports W-CQI, PI2, or S-CQI and a subframe that reports RI or PI1 may be the same subframe. In this case, RI or PI1 is reported without reporting W-CQI, PI2, or S-CQI. Further, it is possible to set so that RI or PI1 or PI2 is not fed back by RRC signaling in step 601. In that case, the terminal apparatus 102 reports only CQI.

  As described above, the number of subframes (number of PUCCHs) allocated to report feedback information related to the narrow band in each DCC is the number of subframes (number of PUCCHs) allocated to report feedback information about the narrow band. Is set to a value at the DCC having the smallest number. In other words, the W-CQI reporting period in each DCC is set to a value in the DCC having the smallest W-CQI reporting period.

At this time, in the DCC in which the configured feedback resource is smaller than the resource necessary for reporting the S-CQI, the reporting procedure described in FIG. 9 uses a part of the S- Report CQI. At that time, the S-CQI having no resource to be transmitted is omitted. That is, in DCC1, with _{J 2} times of the resource, report _{J 2} pieces of S-CQI of _{J 1} single S-CQI. At that time, (J ₁ -J ₂ ) S-CQIs are omitted. Such feedback is repeated K times. In addition, when reporting some S-CQI, you may report periodically from BP with a low frequency, and you may select BP which the terminal device 102 reports. Alternatively, in _DCC1, using _H 2 -1 times of _resources, reporting -1 _H 2 of _H 1 -1 of S-CQI. Although K = 1 in the above description, the present invention is not limited to this. A common K (K is an integer of 1 or more) may be used for each DCC, or an individual K (for example, K ₁ for DCC1, K _{2 for} DCC2, etc.) may be used for each DCC. In this case, H ₁ -1 (= J ₁ · K ₁ ) and H ₂ -1 (= J ₂ · K ₂ ) are compared, and the smaller value is used to determine the W-CQI reporting period. do it. Alternatively, J ₁ and J ₂ may be compared and the smaller value may be used to determine the W-CQI reporting period. In DCC ₁ , J ₁ S-CQIs may be repeatedly reported using J ₂ · K resources.

  By using the feedback information reporting procedure as shown in FIG. 9, it is possible to make the same for all DCCs that report the feedback period, so that efficient feedback can be realized. In addition, the method as shown in FIG. 9 can reduce the overhead of control information for performing feedback while facilitating consistency as compared with the case where feedback is performed independently for each DCC. Also, since there is no redundantly reported feedback information in all DCCs, adaptive control can be realized efficiently.

FIG. 10 shows an example of a procedure (report) for reporting feedback information according to the present embodiment. In the reporting procedure in FIG. 10, a case will be described in which DCCs that report S-CQI and DCCs that do not report S-CQI coexist. That is, a case will be described where DCC1 reports S-CQI and DCC2 does not report S-CQI. Also, the BP number _{J 1} is 4 in DCC1. In this case, a case will be described where the number of feedback resources in each DCC is the number of DCC feedback resources reporting the S-CQI. That is, the feedback resource in each DCC has a size based on the case where the number of BPs is 4.

First, the base station apparatus 101 sets a feedback parameter in the terminal apparatus 102 via RRC (Radio Resource Control) signaling, and instructs periodic feedback (step S1001). The terminal apparatus 102 instructed to perform periodic feedback first reports feedback information in the DCC 1. The terminal apparatus 102 periodically reports the RI and PI1 (step S1002) in DCC1 and the PI2 and W-CQI (step S1003) in DCC1 to the base station apparatus 101 according to the set feedback parameters. Further, the terminal apparatus 102 periodically reports S-CQI in DCC1 (steps S1004 to S1007). Specifically, the terminal apparatus 102 performs S-CQI1 representing the first BP in DCC1 (step S1004), S-CQI2 representing the second BP in DCC1 (step S1005), and the third BP in DCC1. S-CQI3 (step S1006) representing DC and S-CQI4 (step S1007) representing the fourth BP in DCC1 are reported. The S-CQI report shown in steps S1004 to S1007 is periodically performed K times (cycles) between the W-CQI report in step S1003 and the W-CQI report in step S1009 described later. Is called. That is, the S-CQI report in DCC ₁ is periodically performed J ₁ · K (= H ₁ −1) times. In the example shown in FIG. 10, the case of K = 1 is shown.

  Furthermore, the terminal apparatus 102 reports feedback information in DCC2. The terminal apparatus 102 periodically reports the RI and PI1 in the DCC2 (step S1008) and the PI2 and W-CQI (step S1009) in the DCC2 to the base station apparatus 101 according to the set feedback parameters. Further, the terminal apparatus 102 transmits nothing or transmits other information to the feedback resource having the same size as the feedback resource reporting the S-CQI in the DCC 1 (steps S1010 to S1013). Specifically, the terminal device 102 does not transmit anything or transmits other information at the timings indicated in steps S1010 to S1013. The operations shown in steps S1010 to S1013 are repeated periodically by repeating K times (cycles). In the example shown in FIG. 10, the case of K = 1 is shown. Thereafter, the reports or processes shown in steps S1002 to S1013 are repeated periodically.

  Here, the interval of the vertical axis in FIG. 10 does not represent the size of time, and the reporting of each feedback information is not limited to the order shown in FIG. Specifically, the feedback period can be set independently for RI or PI1 and other feedback information. That is, when the periods of W-CQI, PI2, or S-CQI reporting subframes and RI or PI1 reporting subframes are set independently, the reporting order may be changed. Further, a subframe that reports W-CQI, PI2, or S-CQI and a subframe that reports RI or PI1 may be the same subframe. In this case, RI or PI1 is reported without reporting W-CQI, PI2, or S-CQI. Further, it is possible to set so that RI or PI1 or PI2 is not fed back by RRC signaling in step 601. In that case, the terminal apparatus 102 reports only CQI.

As described above, when a DCC that reports S-CQI and a DCC that does not report S-CQI are mixed, in the DCC that does not report S-CQI, the reporting procedure described in FIG. Do not send anything or send other information. That is, in the DCC2, nothing is transmitted or other information is transmitted to the resources for J ₁ · K times. In addition, you may report S-CQI in other DCC using the feedback resource set in DCC which does not report S-CQI.

  By using the feedback information reporting procedure as shown in FIG. 10, the feedback cycle (the W-CQI reporting cycle) can be made the same for all the DCCs to be reported, so that efficient feedback can be realized. In addition, the method as shown in FIG. 10 can reduce the overhead of control information for performing feedback while facilitating consistency as compared with the case where feedback is performed independently for each DCC.

  As described above, by using the method described in the present embodiment, even if the number of BPs differs between DCCs to be reported, the feedback resources for each DCC can be made the same size, so that efficient feedback can be achieved. realizable. Further, compared to the case where feedback is performed independently for each DCC, the overhead of control information for performing feedback can be reduced while ensuring consistency.

  In the above description, a case has been described in which the feedback resource in all DCCs is the maximum or minimum feedback resource in the DCC to be reported. However, the present invention is not limited to this. Feedback resources in a predetermined DCC (for example, primary DCC) may be used as feedback resources in all DCCs. Here, there are cases where the bandwidth of each DCC is larger or smaller than a predetermined DCC. In this case, as the setting of the subframe for reporting the S-CQI, the setting as described above is used (for example, the setting shown in FIG. 6 or FIG. 8 is used for a DCC whose bandwidth is larger than a predetermined DCC, By using the setting shown in FIG. 9 for a DCC whose bandwidth is smaller than a predetermined DCC, S-CQI can be reported efficiently. The primary DCC is set by the base station apparatus 101 as one DCC from all DCCs for each terminal apparatus. Thereby, in the communication system which sets primary DCC, it can feed back more efficiently and effective adaptive control is realizable. Further, the DCC serving as a reference for the size of the feedback resource may be set by the base station apparatus 101 to be specific to the base station apparatus or the terminal apparatus via PDCCH or RRC signaling. Thereby, the flexibility with respect to adaptive control can be improved.

Here, the details about the partial precoder information PI will be described. FIG. 11 is an example of a code book of partial precoder information according to the present embodiment. The size of this code book is 16, and W ¹ _s corresponding to _s is uniquely determined by designating an index s that can be represented by 4 bits as PI1.

FIG. 12 is an example of a code book according to the present embodiment. The size of this code book is 4, and by specifying an index t that can be represented by 2 bits as PI2, W ² _t corresponding to _t is uniquely determined.

  The code book shown in FIGS. 11 and 12 is an example, and other code books can be used. For example, a code book having a code book size different from the code book size shown in FIGS. 11 and 12 can be used.

A suitable precoder can be specified using W ¹ _s indicated by PI1 and W ² _t indicated by PI2. Here, as a suitable precoder, for example, a precoder that increases downlink reception signal power, downlink reception quality, and downlink transmission rate in consideration of a downlink propagation path is adopted. Can do.

  More specifically, the system determines that a suitable precoder F is expressed as F = A (s) B (t), and reports s as PI1 and t as PI2. Here, F is a matrix of the size of the number of layers × the number of antenna ports, and A and B are matrices of a predetermined size. However, the matrix here is a concept including a vector or a scalar. As A and B, for example, an arbitrary matrix that is uniquely determined by specifying s and t as described below can be used.

(1) A (s) = W ¹ _s , B (t) = V ₁ + V ₂ W ² _t . Here, V ₁ and V ₂ are a predetermined matrix composed of 0 and 1 elements, W ¹ _s is a matrix specified by a predetermined code book, and W ² _t is a scalar specified by a predetermined code book.

(2) A (s) = W ¹ _s and B (t) = W ² _t . Here, W ¹ _s and W ² _t are matrices specified by a predetermined code book.

(3) A (s) = [W ¹ _s W ¹ _s ] and B (t) = W ² _t . Here, W ¹ _s and W ² _t are matrices specified by a predetermined code book.

(4) A (s) = K (U, W ¹ _s ), B (t) = [I W ² _t ^T ] ^T. Here, U is a predetermined matrix, I is a unit matrix, and W ¹ _s and W ² _t are matrices specified by a predetermined codebook. Further, K (X, Y) is the Kronecker product, X ^T and the matrix X and the matrix Y is an operator representing a transpose matrix of the matrix X.

  Thus, a suitable precoder expressed using PI1 and PI2 can also be expressed as a precoder that combines the precoder expressed by PI1 and the precoder expressed by PI2. Here, the case where the system determines that F = A (s) B (t) as the combination of the precoders will be described, but F = B (s) A (t) and F = K ( The same effect can be obtained even if other precoder connection methods are determined by the system, such as when expressed as A (s), B (t)).

FIG. 13 is a conceptual diagram of precoding processing according to the present embodiment. Here, a case where the number of antenna ports is 4, the number of layers is 2, and F = W ¹ _s W ² _t will be described. The signal point at each antenna port of each layer is displaced (here, the phase is rotated in the range of 0 to 2π) by W ¹ _s which is a precoder represented by PI1, and further, W ² _t which is a precoder represented by PI2 The signal point at each antenna port is displaced (here, the phase rotates in the range of 0 to 2π). The signal point displacement shown in FIG. 13 is an example, and the present invention is not limited to this.

  When the terminal apparatus 102 first reports PI1, a suitable precoder (the signal point after applying the precoder is obtained from a codebook consisting of a precoder group that gives a specific displacement to the signal point at each antenna port of each layer. Determine the precoder that is preferred. Here, a code book as shown in FIG. 11 is used as a code book for determining PI1. When the terminal apparatus 102 reports PI2 next time, it determines from the codebook a precoder for which the signal point after applying the precoder is suitable for the signal point after applying the precoder represented by the reported PI1. , Report the index as PI2. Here, a code book as shown in FIG. 12 is used as a code book for determining PI2. Alternatively, PI1 may be determined after determining PI2.

Alternatively, the terminal apparatus 102 can determine PI1 and PI2 at the same time. In various combinations of PI1 and PI2, a precoder in which W ¹ _s and W ² _t are combined may be investigated, and various combinations of PI1 and PI2 expressing a suitable precoder may be determined.

  The terminal apparatus 102 can report PI1 and PI2 in units of downlink bandwidth (or downlink component carrier bandwidth), and can also report in units of partial bandwidth. Alternatively, PI1 in downlink bandwidth unit and PI2 in partial bandwidth unit can be reported. FIG. 14 shows an example of an RS for measuring PI. PI1 of downlink bandwidth unit is determined using the measurement result of RS arranged over a wide band, and PI2 of partial bandwidth unit is determined using the determined PI1 and the measurement result of RS within the partial bandwidth. decide.

In the above description, the period for reporting W-CQI between DCCs is the same, and when reporting S-CQI between reporting W-CQI, the BP of S-CQI to report and the subframe to report The method of associating was described. In addition to this, in a system that reports PI1 or PI2 for each BP between W-CQI reports, a BP reporting PI1 or PI2 can be associated with a subframe in the same manner. .
(Second Embodiment)
In the first embodiment, a case has been described in which the number of feedback resources for each DCC is the same when the number of BPs differs between the DCCs to be reported. In the second embodiment of the present invention, a case where the number of feedback resources is set for each DCC according to the number of BPs in the DCC to be reported when the number of BPs differs between the DCCs to be reported will be described. The second embodiment of the present invention will be described below with reference to the drawings.

FIG. 15 shows an example of a feedback information reporting procedure according to this embodiment. In the reporting procedure in FIG. 15, the case where the number of feedback resources in each DCC is set for each DCC according to the number of BPs in each DCC will be described. That is, the feedback period of feedback information for all DCCs is set based on the total number of BPs in all DCCs. Moreover, BP number _{J 1} in DCC1 is 4, a case BP number _{J 2} in DCC2 is 3. That is, the feedback resource in DCC1 has a size based on the case where the BP number is 4, and the feedback resource in DCC2 has a size based on the case where the BP number is 3. The feedback period of feedback information for all DCCs is set based on the case where the number of BPs is 7.

First, the base station apparatus 101 sets a feedback parameter in the terminal apparatus 102 via RRC signaling, and instructs periodic feedback (step S1501). The terminal apparatus 102 instructed to perform periodic feedback first reports feedback information in the DCC 1. The terminal apparatus 102 periodically reports the RI and PI1 (step S1502) in the DCC1 and the PI2 and W-CQI (step S1503) in the DCC1 to the base station apparatus 101 according to the set feedback parameters. Further, the terminal apparatus 102 periodically reports S-CQI in DCC1 (steps S1504 to S1507). Specifically, the terminal apparatus 102 performs S-CQI1 representing the first BP in DCC1 (step S1504), S-CQI2 representing the second BP in DCC1 (step S1505), and the third BP in DCC1. S-CQI3 (step S1506) representing DC and S-CQI4 (step S1507) representing the fourth BP in DCC1 are reported. The S-CQI reports shown in steps S1504 to S1507 are periodically performed K times (cycles) between the W-CQI report in step S1503 and the W-CQI report in step S1509 described later. Is called. That is, the S-CQI report in DCC ₁ is periodically performed J ₁ · K (= H ₁ −1) times. In the example shown in FIG. 15, the case of K = 1 is shown.

Furthermore, the terminal apparatus 102 reports feedback information in DCC2. The terminal apparatus 102 periodically reports the RI and PI1 in DCC2 (step S1508) and the PI2 and W-CQI (step S1509) in DCC2 to the base station apparatus 101 according to the set feedback parameters. Further, the terminal apparatus 102 periodically reports the S-CQI in the DCC 2 using a feedback resource having the same size as the feedback resource for reporting the S-CQI in the DCC 1 (steps S1510 to S1512). Specifically, the terminal apparatus 102 performs S-CQI1 representing the first BP in DCC2 (step S1510), S-CQI2 representing the second BP in DCC2 (step S1511), and the third BP in DCC2. S-CQI3 (step S1512) representing each is reported. The S-CQI report shown in steps S1510 to S1512 is periodically performed by repeating K times (cycles) between the W-CQI report in step S1509 and the W-CQI report in step S1503. That is, the S-CQI report in DCC2 is periodically performed J ₂ · K (= H ₂ −1) times. In the example shown in FIG. 15, the case of K = 1 is shown. Thereafter, the reports or processes shown in steps S1502 to S1512 are repeated periodically.

  Here, the interval of the vertical axis in FIG. 15 does not represent the size of time, and the reporting of each feedback information is not limited to the order shown in FIG. Specifically, the feedback period can be set independently for RI or PI1 and other feedback information. That is, when the periods of W-CQI, PI2, or S-CQI reporting subframes and RI or PI1 reporting subframes are set independently, the reporting order may be changed. Further, a subframe that reports W-CQI, PI2, or S-CQI and a subframe that reports RI or PI1 may be the same subframe. In this case, RI or PI1 is reported without reporting W-CQI, PI2, or S-CQI. Further, it is possible to set so that RI or PI1 or PI2 is not fed back by RRC signaling in step 601. In that case, the terminal apparatus 102 reports only CQI.

  As described above, in each DCC, in the reporting procedure described in FIG. 15, the number of subframes (number of PUCCHs) allocated to report feedback information regarding a narrow band in each DCC is the number of BPs in each DCC. Set by. Further, the feedback period of feedback information for all DCCs is set based on the total number of BPs in all DCCs to report. At that time, the terminal apparatus 102 sets the reporting timing (feedback resource) of feedback information in a certain DCC with reference to the number of BPs of another DCC in a certain DCC.

  By using the feedback information reporting procedure as shown in FIG. 15, the number of feedback resources in each DCC can be optimized for each DCC. Further, compared to the case where feedback is performed independently for each DCC, the overhead of control information for performing feedback can be reduced while ensuring consistency.

  FIG. 16 is a diagram illustrating an example of a feedback cycle according to the present embodiment. FIG. 16 illustrates a feedback cycle in the feedback information reporting procedure described in FIG. Further, the horizontal axis of FIG. 16 indicates time.

W-CQI and PI2 in DCC1 is the period of the sum _(H j) · _{N P} subframes, _{N OFFSET} subframes as a _reference, are reported in subframe shifted by _CQI. In addition, RI and PI1 in DCC1 have a period of sum (H _j ) · N _P · M _RI which is M _RI times the period of W-CQI and W-PMI, and N _{OFFSET, CQI} + N from the reference subframe _{OFFSET, RI} shifted subframes, i.e. W-CQI and W-PMI further _{N OFFSET} from _are reported in subframe shifted by _RI. Here, H _j = J _j · K + 1 (j = 1, 2,..., M), and J _j is the number of BPs in the j-th DCC. Sum (x) is the sum of the elements of x. Further, the S-CQI is a period of H ₁ · N _P (= (J ₁ · K + 1) · N _P ) subframe, which is a period between the W-CQI report in DCC1 and the W-CQI report in DCC2. Periodically reported. That, S-CQI in DCC1 _is the H 1 · _N period _P subframe _is reported _{J 1 · K (= H 1} -1) times.

Furthermore, W-CQI and PI2 in DCC2 _is the period of H 2 · _{N P} subframes are reported in subframe shifted by _H 1 · _{N P} subframes used for the W-CQI reports in DCC1. Further, RI and PI1 in DCC2 is a period of a _{M RI} times the period of the W-CQI and _{W-PMI sum (H j)} · N P · M RI, subframe used for reporting the RI and PI1 in DCC1 _Are reported in subframes shifted by H ₁ · N _P · M _RI . Further, the S-CQI is a period of the H ₂ · N _P (= (J ₂ · K + 1) · N _P ) subframe, which is a period between the W-CQI report in the DCC 2 and the W-CQI report in the DCC 1. Periodically reported. That is, the S-CQI in DCC2 is reported J ₂ · K (= H ₂ −1) times during the H ₂ · N _P subframe period.

Here, in DCC1 and DCC2, each of the S-CQIs reported J ₁ · K times and J ₂ · K times is a CQI representing BP. The CQI in J ₁ and J ₂ BPs is reported sequentially from the CQI in the low frequency BP for each DCC, and J ₁ and J ₂ reports are made to cover the downlink bandwidth. In addition, by repeating the J ₁ and J ₂ reports for K cycles, the J ₁ · K and J ₂ · K reports are made during the H ₁ · N _P and H ₂ · N _P subframes. Is called.

Referring also to FIG. 16 from another point of view, W-CQI and S-CQI in the m DCC are reported in the period of the sum _(H i) · _{N P} to patrol the DCC.

In the above description, the common K is used for each DCC. However, the present invention is not limited to this. A separate K may be used for each DCC (for example, K ₁ for DCC ₁ , K ₂ for DCC _2, etc.). In that case, H _j = J _j · K _j +1.

FIG. 17 shows an example of a feedback information reporting procedure according to this embodiment. In the reporting procedure in FIG. 17, a case will be described in which DCCs that report S-CQI and DCCs that do not report S-CQI coexist. That is, a case will be described where DCC1 reports S-CQI and DCC2 does not report S-CQI. Also, the BP number _{J 1} is 4 in DCC1. At this time, a case will be described in which the feedback resource in the DCC reporting the S-CQI is set for each DCC according to the number of BPs in the DCC. That is, the feedback period of feedback information for all DCCs is set based on the total number of BPs in the DCC that reports S-CQI.

First, the base station apparatus 101 sets a feedback parameter in the terminal apparatus 102 via RRC signaling, and instructs periodic feedback (step S1701). The terminal apparatus 102 instructed to perform periodic feedback first reports feedback information in the DCC 1. The terminal apparatus 102 periodically reports the RI and PI1 (step S1702) in the DCC1 and the PI2 and W-CQI (step S1703) in the DCC1 to the base station apparatus 101 according to the set feedback parameters. Further, the terminal apparatus 102 periodically reports S-CQI in DCC1 (steps S1704 to S1707). Specifically, the terminal apparatus 102 performs S-CQI1 representing the first BP in DCC1 (step S1704), S-CQI2 representing the second BP in DCC1 (step S1705), and the third BP in DCC1. S-CQI3 (step S1706) representing DC and S-CQI4 (step S1707) representing the fourth BP in DCC1 are reported. The S-CQI reports shown in steps S1704 to S1707 are periodically performed by repeating K times (cycles) between the W-CQI report in step S1703 and the W-CQI report in step S1709 described later. . That is, the S-CQI report in DCC ₁ is periodically performed J ₁ · K (= H ₁ −1) times. In the example shown in FIG. 17, the case of K = 1 is shown.

  Further, the terminal apparatus 102 reports feedback information in the DCC 2 that does not report S-CQI. The terminal apparatus 102 periodically reports RI and PI1 in DCC2 (step S1708) and PI2 and W-CQI (step S1709) in DCC2 to the base station apparatus 101 according to the set feedback parameters. Thereafter, the reports or processes shown in steps S1702 to S1709 are repeated periodically.

  Here, the interval between the vertical axes in FIG. 17 does not represent the magnitude of time, and the reporting of each feedback information is not limited to the order shown in FIG. Specifically, the feedback period can be set independently for RI or PI1 and other feedback information. That is, when the periods of W-CQI, PI2, or S-CQI reporting subframes and RI or PI1 reporting subframes are set independently, the reporting order may be changed. Further, a subframe that reports W-CQI, PI2, or S-CQI and a subframe that reports RI or PI1 may be the same subframe. In this case, RI or PI1 is reported without reporting W-CQI, PI2, or S-CQI. Further, it is possible to set so that RI or PI1 or PI2 is not fed back by RRC signaling in step 601. In that case, the terminal apparatus 102 reports only CQI.

  As described above, even when a DCC that reports S-CQI and a DCC that does not report S-CQI coexist, a feedback resource reporting procedure as shown in FIG. It can be optimized every time. Further, compared to the case where feedback is performed independently for each DCC, the overhead of control information for performing feedback can be reduced while ensuring consistency.

  As described above, by using the method described in this embodiment, feedback resources in each DCC can be optimized for each DCC even when the number of BPs differs between the DCCs to be reported. Further, compared to the case where feedback is performed independently for each DCC, the overhead of control information for performing feedback can be reduced while ensuring consistency.

In the above description, the W-CQI reporting period is set for each DCC, and when reporting S-CQI between W-CQI reporting, each DCC reports the BP of the S-CQI to be reported. The method of associating with subframes is described. In addition to this, in a system that reports PI1 or PI2 for each BP between W-CQI reports, a BP reporting PI1 or PI2 can be associated with a subframe in the same manner. .
(Third embodiment)
In the third embodiment of the present invention, functional blocks of the base station apparatus 101 and the terminal apparatus 102 according to the present invention will be described. The third embodiment of the present invention will be described below with reference to the drawings.

  FIG. 18 is a schematic diagram illustrating an example of the configuration of the base station apparatus 101 according to the present embodiment. The base station apparatus 101 includes an encoding unit 1801, a scrambling unit 1802, a modulation unit 1803, a layer mapping unit 1804, a precoding unit 1805, a reference signal generation unit 1806, a resource element mapping unit 1807, an OFDM signal generation unit 1808, a transmission antenna (base). (Station side transmission antenna) 1809, reception antenna (base station side reception antenna) 1810, reception signal processing unit 1811, feedback information processing unit 1812, and upper layer 1813.

  Each transmission data (bit sequence) for each codeword (transmission data sequence) sent from the upper layer 1813 is subjected to error correction coding and rate mapping processing in the encoding unit 1801 and multiplied by a scrambling code in the scrambling unit 1802. Then, the modulation unit 1803 performs modulation processing such as PSK (Phase Shift Keying) modulation and QAM (Quadrature Amplitude Modulation) modulation. At this time, the transmission data sequence sent from the higher layer 1813 includes control data for RRC signaling. The layer mapping unit 1804 distributes the modulation symbol sequence output from the modulation unit 1803 for each layer. Precoding section 1805 performs precoding processing on the modulation symbol sequence for each layer. More specifically, the precoding matrix is multiplied.

  The reference signal generation unit 1806 generates a downlink RS. Resource element mapping section 1807 maps the modulation symbol sequence precoded by precoding section 1805 and the RS generated by reference signal generation section 1806 to a predetermined resource element.

  The resource block group output from the resource element mapping unit 1807 is converted into an OFDM signal by the OFDM signal generation unit 1808 and transmitted from the transmission antenna 1809 as a downlink transmission signal.

  On the other hand, the uplink reception signal received by the reception antenna 1810 is subjected to predetermined signal processing in the reception signal processing unit 1811, and then feedback information is sent to the feedback information processing unit 1812. Feedback information processing section 1812 uses the partial precoder information reported from terminal apparatus 102 to determine a precoding matrix to be used in precoding section 1805. Here, as described in the above embodiments, the timing for reporting each content can be set differently for each terminal device. Therefore, the upper layer 1813 sets the RI, CQI, and PI period and offset in the feedback information processing unit 1812, and the feedback information processing unit 1812 receives the signal transmitted from the received signal processing unit 1811 at any timing. It is possible to identify which content is included in the device 102 and realize suitable adaptive control in each terminal device 102.

  FIG. 19 is a schematic diagram illustrating an example of the configuration of the terminal device 102 (reception device) according to the present embodiment. The terminal apparatus 102 includes a reception antenna (terminal reception antenna) 1901, an OFDM signal demodulation unit 1902, a resource element demapping unit 1903, a filter unit 1904, a layer demapping unit 1905, a demodulation unit 1906, a descrambling unit 1907, and a decoding unit 1908. A higher layer 1909, a reference signal measurement unit 1910, a feedback information generation unit 1911, a transmission signal generation unit 1912, and a transmission antenna (terminal-side transmission antenna) 1913.

  The downlink received signal received by the receiving antenna 1901 is subjected to OFDM demodulation processing in the OFDM signal demodulating section 1902, and a resource block group is output. The resource element demapping unit 1903 outputs the RS to the reference signal measuring unit 1910 and outputs the received signal in the resource element other than the resource element to which the RS is mapped to the filter unit 1904. The filter unit 1904 performs a filtering process on the received signal output from the resource element demapping unit 1903. The filtered signal is in a state where a decoding process corresponding to precoding in the precoding unit 1805 has already been performed, and a signal for each layer is output from the filter unit 1904. The layer demapping unit 1905 performs a combining process corresponding to the layer mapping unit 1804, and converts a signal for each layer into a signal for each codeword. The demodulated unit 1906 performs demodulation processing corresponding to the modulation processing in the modulation unit 1803 on the converted signal for each codeword, and the descrambling unit 1907 multiplies the conjugate code of the scrambling code used in the scrambling unit 1802. After (division by scrambling code), the decoding unit 1908 performs rate demapping processing and error correction decoding processing to obtain received data for each codeword and send it to the upper layer 1909. Here, the reception data sent to the upper layer 1909 includes control data for RRC signaling, and the upper layer 1909 obtains a command from the base station apparatus 101 by RRC signaling.

  Here, in the filtering process performed by the filter unit 1904, a method such as ZF (Zero Forcing), MMSE (Minimum Mean Square Error), or MLD (Maximum Likelihood Detection) is used for the received signal for each receiving antenna 1901. A signal for each layer in FIG. 18 is detected.

  On the other hand, in the reference signal measurement unit 1910, the downlink RS acquired by the resource element demapping unit 1903 is measured, and the measurement result is output to the feedback information generation unit 1911. Based on the feedback mode, feedback information generation section 1911 generates feedback information such as partial precoder information, RI, and CQI using the downlink RS measurement result output from reference signal measurement section 1910.

  The feedback information generated in the feedback information generation unit 1911 is converted into a transmission signal in the transmission signal generation unit 1912 and transmitted as an uplink transmission signal via the transmission antenna 1913.

  Here, as described in the above embodiments, the timing for reporting each content can be set differently for each terminal device 102. Therefore, the upper layer 1909 sets the RI / CQI / PI period and offset in the feedback information generation unit 1911 and the transmission signal generation unit 1912, and the feedback information processing unit 1812 generates a signal including any content at any timing. Identify what to do. Further, the transmission signal generation unit 1912 identifies which signal includes which content is transmitted at which timing.

  In each of the above embodiments, the case where a suitable precoder is reported to the base station as feedback information has been described. However, even when an inappropriate precoder is reported, the same processing is used to perform precoding at the base station. The recording process can be performed efficiently. In this case, for example, it is possible to use a method of selecting a precoder from the code book that reduces the received signal power in consideration of the propagation path.

  Note that a program for realizing the functions of all or part of the base station apparatus 101 in FIG. 18 or all or part of the terminal apparatus 102 in FIG. 19 is recorded on a computer-readable recording medium. Processing of each unit may be performed by causing a computer system to read and execute a program recorded on a medium. Here, the “computer system” includes an OS and hardware such as peripheral devices.

  Further, the “computer system” includes a homepage providing environment (or display environment) if a WWW system is used.

  The “computer-readable recording medium” refers to a storage device such as a flexible medium, a magneto-optical disk, a portable medium such as a ROM and a CD-ROM, and a hard disk incorporated in a computer system. Furthermore, the “computer-readable recording medium” dynamically holds a program for a short time like a communication line when transmitting a program via a network such as the Internet or a communication line such as a telephone line. In this case, a volatile memory in a computer system serving as a server or a client in that case, and a program that holds a program for a certain period of time are also included. The program may be a program for realizing a part of the functions described above, and may be a program capable of realizing the functions described above in combination with a program already recorded in a computer system.

  Further, the functions of all or part of the base station apparatus 101 in FIG. 18 and all or part of the terminal apparatus 102 in FIG. 19 may be integrated and realized in an integrated circuit. Each functional block of the base station apparatus 101 and the terminal apparatus 102 may be individually chipped, or a part or all of them may be integrated into a chip. Further, the method of circuit integration is not limited to LSI, and may be realized by a dedicated circuit or a general-purpose processor. In addition, when an integrated circuit technology that replaces LSI appears due to progress in semiconductor technology, an integrated circuit based on the technology can also be used.

  The embodiment of the present invention has been described in detail with reference to the drawings. However, the specific configuration is not limited to this embodiment, and includes design changes and the like without departing from the gist of the present invention.

  The present invention is suitable for use in a wireless terminal device, a wireless base station device, a wireless communication system, and a wireless communication method.

DESCRIPTION OF SYMBOLS 101 ... Base station apparatus 102 ... Terminal apparatus 103 ... Downlink transmission signal 104 ... Feedback information 1801 ... Encoding part 1802 ... Scrambler 1803 ... Modulation part 1804 ... Layer mapping part 1805 ... Precoding part 1806 ... Reference signal generation part 1807 ... Resource Element mapping section 1808 ... OFDM signal generation section 1809 ... transmission antenna 1810 ... reception antenna 1811 ... reception signal processing section 1812 ... feedback information processing section 1813 ... upper layer 1901 ... reception antenna 1902 ... OFDM signal demodulation section 1903 ... resource element demapping section 1904: Filter unit 1905 ... Layer demapping unit 1906 ... Demodulation unit 1907 ... Descramble unit 1908 ... Decoding unit 1909 ... Upper layer 1910 ... Reference signal measurement unit 1911 ... Dobakku information generating unit 1912 ... the transmission signal generation unit 1913 ... transmitting antenna 2001 ... base station apparatus 2002 ... the terminal apparatus 2003 ... downlink transmission signal 2004 ... feedback information

Claims (17)

A terminal device that communicates with a base station device in a communication system capable of aggregating a plurality of component carriers,
A feedback period for periodically reporting a reception quality indicator specifying a suitable transmission rate in a frequency bandwidth for each component carrier is set to be the same for each of the component carriers, and the feedback period is used. A terminal device reporting to the base station device.   The terminal apparatus according to claim 1, wherein the feedback period is set based on a frequency bandwidth in one of the component carriers.   The terminal apparatus according to claim 2, wherein the feedback period is set based on the frequency bandwidth in the component carrier having the largest frequency bandwidth.   The terminal apparatus according to claim 2, wherein the feedback period is set based on the frequency bandwidth in the component carrier having the smallest frequency bandwidth.   The terminal apparatus according to claim 2, wherein the feedback period is set based on the frequency bandwidth in a primary component carrier designated by the base station apparatus from the component carriers.   The terminal apparatus according to claim 1, wherein the feedback period is set based on a frequency bandwidth in all of the component carriers.   The terminal apparatus according to claim 1, wherein a reception quality index that specifies a suitable transmission rate in a frequency bandwidth for each component carrier is reported cyclically for each component carrier.   The terminal according to claim 7, wherein the reception quality indicator specifying a suitable transmission rate in the frequency bandwidth for each component carrier is reported cyclically by the same feedback period in all of the component carriers. apparatus.   The terminal according to claim 7, wherein the reception quality indicator that specifies a suitable transmission rate in the frequency bandwidth for each component carrier is reported cyclically by a feedback period unique to each component carrier. apparatus. A base station device that communicates with a terminal device in a communication system capable of aggregating a plurality of component carriers,
A feedback period for periodically reporting a reception quality indicator specifying a suitable transmission rate in a frequency bandwidth for each component carrier is set to be the same for each of the component carriers, and the feedback period is used. A base station apparatus that notifies the terminal apparatus of control information for causing the base station apparatus to report.   The base station apparatus according to claim 10, wherein the feedback period is set based on a frequency bandwidth in any of the component carriers.   The base station apparatus according to claim 10, wherein the feedback period is set based on a frequency bandwidth in all of the component carriers. A communication system that performs communication between a base station device and a terminal device that can aggregate a plurality of component carriers,
The base station device
A feedback period for periodically reporting a reception quality indicator specifying a suitable transmission rate in a frequency bandwidth for each component carrier is set to be the same for each of the component carriers, and the feedback period is used. Notifying the terminal device of control information for causing the base station device to report,
The terminal device
Based on the control information notified from the base station apparatus, a reception quality indicator designating a suitable transmission rate in the frequency bandwidth for each component carrier is periodically reported to the base station apparatus. Communication system.   The communication system according to claim 13, wherein the feedback period is set based on a frequency bandwidth in any one of the component carriers.   The communication system according to claim 13, wherein the feedback period is set based on a frequency bandwidth in all of the component carriers. A communication method of a terminal device that communicates with a base station device in a communication system capable of aggregating a plurality of component carriers,
A feedback period for periodically reporting a reception quality indicator specifying a suitable transmission rate in a frequency bandwidth for each component carrier is set to be the same for each of the component carriers, and the feedback period is used. A communication method comprising reporting to the base station apparatus. A communication method of a base station device that communicates with a terminal device in a communication system capable of aggregating a plurality of component carriers,
A feedback period for periodically reporting a reception quality indicator specifying a suitable transmission rate in a frequency bandwidth for each component carrier is set to be the same for each of the component carriers, and the feedback period is used. A communication method comprising: notifying the terminal device of control information for causing the base station device to report.