WO2012068905A1 - Method and system for channel information feedback under comp - Google Patents

Abstract

Disclosed are a method and system for channel information feedback under CoMP, where the terminal can perform channel information feedback on main serving cells and coordinate cells outside of the main serving cells according to their respective feedback mode and/or different granularities under Coordinated Multipoint transmission/reception. The main serving cells refer to cells that send physical downlink control information for the user. The coordinate cells refer to a single or multiple cells that require measurements and feedback of channel status information. This invention achieves the technology of channel information feedback under CoMP, supporting the channel information feedback under CoMP; and dynamically supporting single cell CSI information feedback and multiple cell CSI information feedback, thus adapting to the dynamic switching between different transmission technologies.

Description

 Method and system for channel information feedback in CoMP mode

 The present invention relates to the field of communications, and in particular to a method and system for channel information feedback in a CoMP (Multipoint Cooperative Transmission) mode. Background technique

 With the LTE-A demand, people pay more and more attention to the average spectral efficiency of the cell and the efficiency of the cell edge spectrum. In comparison, the spectrum efficiency of the cell edge is the most concerned, mainly because the uplink and downlink of the LTE-A system are both frequency division systems based on OFDM (or some variant of OFDM). . Different from the traditional wireless communication system based on CDMA as the basic multiple access multiplexing method, the LTE-A system has no processing gain, and there is almost no interference problem in the cell because of the complete frequency division orthogonality, but the interference processing at the cell edge is relatively Tricky.

 At present, there are three main methods for handling interference at the edge of a cell in LTE: 1. Interference randomization; 2. Interference cancellation; 3. Interference coordination (avoidance).

Specifically, the method of interference randomization generally uses frequency hopping, time hopping, direct spreading, or code hopping to mitigate the influence of interference between cells. The advantage is that no network planning is required, and signaling support is hardly needed. However, it only mitigates the interference and does not eliminate the interference fundamentally. Although the interference cancellation method can use some algorithms to eliminate the interference, it usually needs additional physical entities (such as multi-antenna technology) to basically eliminate the interference, sometimes these The condition may not be satisfied; the last major method of interference coordination (avoidance) is to exchange some information between cells, and use some algorithms to make each cell automatically select appropriate resources according to the feedback information of other cells and its own situation. The transmission is carried out, thereby realizing the efficient utilization of inter-cell resources, and minimizing the chance of resource collision and utilization between cells, and finally achieving the improvement of the cell edge performance, and emphasizing that the inter-cell contention of the same time-frequency resources is avoided as much as possible to cause interference. Due to the distance between multiple users in the cell edge The antenna distances of the neighboring cells are not much different. Therefore, using the transmit antennas of multiple cells to achieve higher capacity and reliable transmission of the wireless link at the cell edge has become a research focus.

 One problem that exists in multipoint coordinated transmission is: Within the same node, when there are multiple nodes cooperating users, the same cell will have both the target user of the collaborative service and the target user of the non-cooperative service. These two different types of users differ in terms of control information design, data transmission methods, channel status information, and quality information.

 At present, there is no relatively complete technology to support channel information feedback in CoMP mode, so it is unable to dynamically support single-cell CSI (channel state information) information feedback and multi-cell CSI information feedback, and cannot adapt to different transmissions. Dynamic switching between technologies. Summary of the invention

 In view of this, the main object of the present invention is to provide a method and system for channel information feedback in CoMP mode to support channel information feedback in CoMP mode.

 In order to achieve the above object, the technical solution of the present invention is achieved as follows:

 A method for channel information feedback in a CoMP multi-point coordinated transmission mode, the method comprising: in a coordinated multi-point transmission mode, the terminal according to a respective feedback mode and/or different for the primary serving cell and other coordinated cells outside the primary serving cell The granularity of the channel information feedback;

 The primary serving cell refers to: a cell that sends physical downlink control information to the user; the coordinated cell refers to: one or more cells that need to measure and feed back channel state information.

 The feedback to the primary serving cell follows any one or more feedback modes supported by a single cell closed-loop spatial multiplexing transmission mode:

 The periodic wideband channel quality indicator CQI/precoding matrix indicates PMI feedback, periodic wideband CQI/PMI+subband CQI feedback mode, aperiodic wideband feedback mode, aperiodic user equipment UE selects subband feedback mode or aperiodic The feedback mode of the sub-band of the high-level configuration.

Wherein, the respective modes of the other coordinated cells outside the primary serving cell are used: When the CSI information of the channel state information of other cells other than the serving cell is fed back, the mode of the wideband CQI/PMI is used;

 Different granularity feedback is used for other coordinated cells outside the primary serving cell: a smaller codebook set and/or a smaller channel quality indicator set than the primary serving cell is used for the coordinated cell other than the primary serving cell.

 The CSI information of the other coordinated cells outside the primary serving cell is fed back on a different channel from the primary serving cell; and the CSI information of the primary serving cell is used in a single-cell closed-loop spatial multiplexing transmission mode. Any feedback on the feedback channel; the other coordinated cells are periodically reported on the physical uplink shared channel;

 Alternatively, the CSI information of other coordinated cells outside the primary serving cell is fed back in a different time slot from the primary serving cell.

 The method further includes:

 For all or part of the coordinated cells outside the primary serving cell in the cooperative set, a differential CQI is fed back for each cell;

 In the case where there are multiple data streams (layers), the CQI that feeds back the difference for each cell means: each data stream is differentially fed back to the wideband CQI of the primary serving cell.

 The timing relationship between the CSI information of other coordinated cells outside the primary serving cell and the time slot different from the primary serving cell is:

 First, the channel information of the primary serving cell is fed back, and the channel information of all or part of the coordinated cells is respectively fed back on the subsequent feedback time slots.

 The method further includes:

 When it is required to feed back the PCI between different nodes, and the channel information of other cells is fed back on the physical uplink shared channel PUSCH, the PCI information and the channel information of other cells are fed back in the same subframe;

When the channel information of other cells is fed back on the PUCCH, the PCI information is specified. Feedback is performed on independent subframes, or feedback is performed on the same subframe as the RI.

 Wherein, if feedback is performed on the PUCCH, and feedback phase correction PCI information is required,

The feedback period of PCI is the same as the rank information RI feedback period or an integer multiple of the RI feedback period.

 The timing relationship of the PCI feedback is any one or more of the following:

 a) if the RI and the PCI are fed back in the same subframe, the CSI information of each cell in the cooperation set is fed back in the subframe within the RI/PCI feedback interval; the feedback timing relationship at this time is: PCI or RI The feedback period is M_ri* ( H+Hc ) *Np;

 b) feeding back the CSI information feedback of each cell in the cooperation set on different time slots in the RI feedback interval if the PCI performs feedback on a separate subframe; wherein the cooperation The CSI information of each cell in the set includes PCI information; the feedback timing relationship is: the feedback period of the RI is M_ri* ( H+1+Hc ) *Np;

 The Np represents a CQI/PMI feedback period; the value of the H is different in different feedback modes;

 When the primary serving cell is based on broadband feedback, H=l;

 When the sub-band mode feedback is selected for the primary serving cell and the broadband feedback mode is used for other cells, H=J*K+1; where J represents the number of reserved bandwidths of the feedback CQI; K represents feedback on the reserved bandwidth. The number of CQIs, He indicates the number of slots required for feedback from other coordinated cells in the coordinated set except the primary serving cell, where He is equal to the number of other coordinated cells;

 When the primary sub-band mode feedback is used for the primary serving cell and other coordinated cells, Hc=Nc*H; Nc represents the number of other coordinated cells to be fed back;

 M_ri is a positive integer;

 c) If feedback is performed on the PUCCH and there is no need to feed back PCI, the feedback timing relationship at this time is: The feedback period of the RI is M_ri* ( H+Hc ) *Np , between the slots of the two feedback RIs, The feedback is performed on the feedback subframe after the CSI information of the primary serving cell is fed back.

Wherein, when the PCI information needs to be fed back, and the PCI performs feedback on independent time slots At the time, the PCI performs feedback on the time slot between the CSI information feedback of the primary serving cell and the CSI information feedback of other cells outside the primary serving cell.

 A system for channel information feedback in a CoMP mode, the system comprising a feedback distinguishing unit, a primary serving cell feedback unit, and a coordinated cell feedback unit;

 The feedback distinguishing unit is configured to confirm that the current multi-point coordinated transmission mode is present, and notify the primary serving cell feedback unit and the coordinated cell feedback unit of the situation;

 The primary serving cell feedback unit and the coordinated cell feedback unit are configured to distinguish the primary serving cell from other coordinated cells outside the primary serving cell, and respectively perform the respective feedback modes for the primary serving cell and other coordinated cells outside the primary serving cell. And/or different granularity for channel information feedback; wherein, the primary serving cell refers to: a cell that sends physical downlink control information to the user; the coordinated cell refers to: one or more cells that need to measure and feed back channel state information. .

 When the primary serving cell feedback unit feeds back to the primary serving cell, it is used to support any one or more feedback modes in a transmission mode of single-cell closed-loop spatial multiplexing:

 Periodic wideband CQI/PMI feedback, periodic wideband CQI/PMI+ subband CQI feedback mode, aperiodic wideband feedback mode, aperiodic UE selection subband feedback mode or aperiodic high layer configuration subband feedback mode.

 When the coordinated cell feedback unit uses the respective mode feedback for the other coordinated cells outside the primary serving cell, it is used to: when the CSI information of other cells other than the primary serving cell is fed back, the broadband CQI/PMI is used. Mode

 When the coordinated cell feedback unit uses different granularity feedback for other coordinated cells outside the primary serving cell, it is used to: use a codebook set smaller than the primary serving cell for the coordinated cell other than the primary serving cell and/or Or a smaller set of channel quality indications.

 The primary serving cell feedback unit and the coordinated cell feedback unit are used for:

The CSI information of other coordinated cells outside the primary serving cell is different from that of the primary serving cell. Feedback is performed on the channel; the CSI information of the primary serving cell is fed back on any one of the feedback channels used in the single cell closed-loop spatial multiplexing transmission mode; and the other coordinated cells are in the physical uplink shared channel Periodic reporting;

 Alternatively, the CSI information of other coordinated cells outside the primary serving cell is fed back in a different time slot from the primary serving cell.

 The coordinated cell feedback unit is further configured to:

 For all or part of the coordinated cells outside the primary serving cell in the cooperative set, a differential CQI is fed back for each cell;

 In the case where there are multiple data streams (layers), the CQI that feeds back the difference for each cell means: each data stream is differentially fed back to the wideband CQI of the primary serving cell.

 The CSI information of the other coordinated cells outside the primary serving cell, when the primary serving cell feedback unit and the coordinated cell feedback unit perform feedback on different time slots from the primary serving cell, are used to respectively follow the cell corresponding to the corresponding cell. The following timing relationship:

 First, the channel information of the primary serving cell is fed back, and the channel information of all or part of the coordinated cells is respectively fed back on the subsequent feedback time slots.

 If the feedback is performed on the PUCCH and the phase correction PCI information needs to be fed back, the feedback period of the PCI is the same as the rank information RI feedback period or an integer multiple of the RI feedback period.

 When the feedback is performed on the cell corresponding to the cell, the primary serving cell feedback unit and the coordinated cell feedback unit are used to apply any one or more of the following in the process of implementing the timing relationship of the PCI feedback:

 a) if the RI and the PCI are fed back in the same subframe, the CSI information of each cell in the cooperation set is fed back in the subframe within the RI/PCI feedback interval; the feedback timing relationship at this time is: PCI or RI The feedback period is M_ri* ( H+Hc ) *Np;

And b) feeding back the CSI information feedback of each cell in the cooperation set on different time slots in the RI feedback interval if the PCI performs feedback on an independent subframe; The CSI information of each cell in the cooperation set includes PCI information; the feedback timing relationship is: the feedback period of the RI is M_ri* ( H+1+Hc ) *Np;

 The Np represents a CQI/PMI feedback period; the value of the H is different in different feedback modes;

 When the primary serving cell is based on broadband feedback, H=l;

 When the sub-band mode feedback is selected for the primary serving cell and the broadband feedback mode is used for other cells, H=J*K+1; where J represents the number of reserved bandwidths of the feedback CQI; K represents feedback on the reserved bandwidth. The number of CQIs, He indicates the number of slots required for feedback from other coordinated cells in the coordinated set except the primary serving cell, where He is equal to the number of other coordinated cells;

 When the primary sub-band mode feedback is used for the primary serving cell and other coordinated cells, Hc=Nc*H; Nc represents the number of other coordinated cells to be fed back;

 M_ri is a positive integer;

 c) If feedback is performed on the PUCCH and there is no need to feed back PCI, the feedback timing relationship at this time is: The feedback period of the RI is M_ri* ( H+Hc ) *Np , between the slots of the two feedback RIs, The feedback is performed on the feedback subframe after the CSI information of the primary serving cell is fed back.

 The primary serving cell feedback unit is further configured to:

 When the PCI information needs to be fed back, and the PCI feeds back on the independent time slot, the PCI feeds back on the time slot between the primary serving cell CSI information feedback and other cell CSI information feedback outside the primary serving cell.

 In summary, the method for implementing channel information feedback in CoMP mode can support channel information feedback in CoMP mode, and can dynamically support single-cell CSI information feedback and multi-cell. Feedback of CSI information, which can adapt to dynamic switching between different transmission technologies. DRAWINGS

FIG. 1 is a periodic broadband CQI/PMI (channel quality according to an embodiment of the present invention) Indicator/precoding matrix indicator, channel quality indicator/provisioning code head array indication)

Schematic diagram of the extension method in CoMP;

 2 is a broadband CQI/PMI and subband CQI feedback based on an embodiment of the present invention.

An extended schematic diagram in CoMP;

 FIG. 3 is a flowchart of channel information feedback in a CoMP mode according to an embodiment of the present invention; FIG. 4 is a system diagram of channel information feedback in a CoMP mode according to an embodiment of the present invention. detailed description

 In general, in the coordinated multi-point transmission mode, the UE (User Equipment) can feedback the primary serving cell and other coordinated cells outside the primary serving cell according to their respective feedback modes and/or granularity.

 For example, the feedback to the primary serving cell may follow any of the feedback modes supported in the single cell closed loop spatial multiplexing transmission mode. The feedback mode supported by the single-cell closed-loop spatial multiplexing transmission mode refers to: periodic wideband CQI/PMI feedback, periodic wideband CQI/PMI+ subband CQI feedback mode, aperiodic wideband feedback mode, non The periodic UE selects a feedback mode of the subband and a feedback mode of the aperiodic high layer configuration subband. When the CSI information of other cells other than the primary serving cell outside the primary serving cell is fed back, the method of using the wideband CQI/PMI may be adopted; or the coded base smaller than the primary serving cell may be used for the coordinated cell other than the primary serving cell. Set and/or smaller channel quality indicator sets;

 Of course, when the CSI feedback is sent to other cells other than the primary serving cell, the feedback manner may also be the same as that of the primary serving cell.

In addition, the CSI information of other coordinated cells outside the primary serving cell may be fed back on different channels. The CSI information of the primary serving cell may be subjected to periodic reporting on the physical uplink shared channel (traffic channel) for other coordinated cells according to any feedback mode supported by the single cell closed-loop spatial multiplexing transmission mode. As a matter of course, the CSI information of other coordinated cells outside the primary serving cell may be reported in the PUCCH (Physical Uplink Control Channel) period, but the CSI information of the other coordinated cells is reported in a subframe different from the primary serving cell CSI information.

 Moreover, for all or part of the coordinated cells outside the primary serving cell in the cooperative set, a differential CQI and a PMI may be fed back for each cell. The differential CQI refers to: a difference between the wideband CQI corresponding to the primary serving cell. In the case where there are multiple data streams (layers), the difference may be different from the broadband CQI of the primary serving cell on each data stream; or some or all of the cells outside the primary serving cell in the cooperation set may be used. Long periods and/or coarser quantization granularity are used for feedback.

 In addition, when it is required to feed back the PCI between different nodes, and the channel information (CQI, PMI) of other cells is fed back on the physical uplink shared channel (PUSCH), the channel information of the PCI information and other cells may be in the same subframe. Give feedback. When the channel information (CQI, PMI) of other cells is fed back on the PUCCH, the PCI information may be fed back on a specific independent subframe or fed back in the same subframe as the RI (rank indicator).

 It should be noted that, based on multi-point coordinated transmission, CSI information feedback of different nodes may have a timing relationship, such as:

 After the UE is triggered to feedback the channel information of the primary serving cell and other coordinated cells, the channel information of the other cells is fed back by means of periodic feedback; or after the UE is triggered to feedback the channel information of the primary serving cell and other coordinated cells, Subsequent k+n to k+n+m subframes provide feedback to the channel information of other cells. Where k is the subframe number of the feedback indication information, n>=l, m>=0.

 Specifically, if feedback is performed on the PUCCH and feedback is required, the feedback period of the PCI is the same as the RI feedback period or an integer multiple of the RI feedback period. The specific way of PCI feedback at this time can be:

a) When the RI and PCI are fed back in the same subframe, then on the subframe within the RI/PCI feedback interval Feedback on CSI information for each cell in the collaborative set. The feedback timing relationship at this time is: The feedback period of PCI or RI is M_ri* ( H+Hc ) *Np;

 b) When the PCI performs feedback on the independent subframe, the CSI information of each cell in the cooperation set is fed back in the subframe within the RI feedback interval. The feedback timing relationship at this time is: The feedback period of RI is M_ri* ( H+1+Hc ) *Np;

 Where Np represents the CQI/PMI feedback period. The PCI performs feedback on the subframe between the CSI information feedback of the primary serving cell and the CSI information feedback of other cells outside the primary serving cell.

 When the primary serving cell is based on broadband feedback, H = l;

 When subband mode feedback is selected for the primary serving cell and broadband feedback mode is used for other cells, H=J*K+1. Where J denotes the number of specific bandwidths of the feedback CQI; K denotes the number of CQIs fed back on a specific bandwidth, and He denotes the number of slots required for feedback of other coordinated cells other than the primary serving cell in the coordinated set, When He is equal to the number of other coordinated cells.

 When the UE uses the selective subband mode feedback for the primary serving cell and other coordinated cells, Hc=Nc*H, and Nc indicates the number of other coordinated cells to be fed back.

 M_ri is a positive integer.

 c) If feedback is performed on the PUCCH and there is no need to feed back PCI, the feedback timing relationship at this time is: The feedback period of the RI is M_ri* ( H+Hc ) *Np, between the subframes of the two feedback RIs, The feedback is performed on the feedback subframe after the CSI information of the primary serving cell is fed back.

 In practical applications, the present invention relates to a bearer configuration of feedback information, a trigger configuration of a feedback mode, and a timing configuration of feedback in a CoMP-supported transmission mode. The feedback may refer to periodic feedback or aperiodic feedback; the feedback mode may be broadband feedback, UE selected subband feedback, and high layer configured subband feedback.

After the UE obtains the cooperation set information through the RRC signaling delivered by the network, the channel measurement may be performed based on the cell list information in the cooperation set, and the measurement mode, the feedback mode, and the feedback timing are determined according to the network side configuration. In CoMP, in order to ensure better PDCCH signal reception quality, the primary serving cell is usually the cell with the best received power. In order to maintain compatibility with LTE R8, R9 and R10, the feedback of the channel information of the primary serving cell may be fed back by the feedback mode of LTE R8/R9/R10, or supported by the transmission mode of LTE-A following single-cell closed-loop spatial multiplexing. Any feedback mode. The feedback mode supported by the single-cell closed-loop spatial multiplexing transmission mode refers to: periodic wideband CQI/PMI feedback, periodic wideband CQI/PMI+ subband CQI feedback mode, aperiodic wideband feedback mode, non The periodic UE selects a feedback mode of the subband and a feedback mode of the aperiodic high layer configuration subband.

 In order to reduce overhead, for the other coordinated cells other than the primary serving cell, the following two methods for compressing the feedback overhead are given:

 1) For other coordinated cells outside the primary serving cell, only the CQI and PMI of the broadband are fed back; the broadband CQI and PMI refer to: When the UE is configured to report the CQI, the UE reports only one broadband CQI based on multiple transmission subbands. When the PMI needs to be reported, the UE only has one PMI based on multiple transmission subbands.

2) Configure different CQI and PMI feedback granularities for other coordinated cells outside the primary serving cell. For example: primary serving cell CG CG ^ - ¹ correspond to the same cooperative cell C2, the primary serving cell ^{k * PMI ~ k - PMV +} 1 corresponding to the same cell of a cooperating PMl. Where k>=2.

 After the UE is triggered to perform other cell CSI feedback, the UE starts to periodically feed back on the PUCCH or PUSCH. The period for feeding back CSI information of other cells is the same as the period for the UE to feed back the RI; or, after the UE is triggered, only the CSI information of other coordinated cells is fed back once.

 In order to support dynamic handover of single cell transmission and multi-cell transmission, the following methods may be used to feedback other cell information.

Mode 1: The feedback of the CoMP-supported transmission mode and the cooperative set size triggers other cells outside the primary serving cell. When the cooperation set is greater than 1, the channel information of other cells is fed back; otherwise, No feedback is given. The CS/CB and the JP are fed back in a unified manner, that is, for the coordinated cells outside the primary serving cell, each cell is independently fed back, and the CQI, BCI, and/or WCI information of each coordinated cell is respectively fed back; The PCI of each cell relative to the primary serving cell is fed back.

 Mode 2: Determine whether the feedback is based on the single-cell channel information feedback or the multi-cell channel information feedback through the configuration of the transmission mode and the cooperation set. Meanwhile, the signaling is used to indicate feedback based on JP or feedback based on CS/CB. When in accordance with the feedback of the JP, for other cells outside the primary serving cell, the CQI and BCI information of each coordinated cell are fed back. When each cell signal related transmission is required, the PCI of each cell relative to the primary serving cell is simultaneously fed back; During feedback, for other cells outside the primary serving cell, the CQI and WCI information of each coordinated cell is fed back. In this manner, the purpose of reducing the feedback overhead is achieved by adding the indication information to the downlink signaling, where the indication information may be configured on the RRC signaling or the PDCCH.

 When the indication information is carried in the RRC signaling, the PCI feedback indication information PCIFeedBacklndicator: BOOLEAN may be added in the CQI-ReportConfig of the radio resource control IE item; when the indication information is carried in the PDCCH signaling, the CoMP transmission DCI format may be supported. The indication information is added in the (downlink control information format), for example, whether the PCI is fed back by using lbit.

 Method 3: 通知 Notification in an implicit manner. For example, according to the subframe number, the channel information of the CSCB or JP transmission mode is fed back according to a predefined criterion, and single-cell feedback/multi-cell feedback is performed. For example, according to the subframe number, in the feedback period of the two primary serving cell RIs, the other cooperative cells are cyclically fed back according to the CSCB and JP manners; of course, the CQI feedback of other coordinated cells outside the primary serving cell, It can also be performed in a manner different from the CQI of the primary serving cell to reduce the feedback overhead.

 For the related operations performed by the feedback described above, reference may be made to the following embodiments.

 Embodiment 1 : Periodic feedback extension

At periodic feedback, for channel information of other coordinated cells, when it is on PUCCH When the channel information of the cell is fed back, it can be configured as follows.

 1. Use broadband CQI and PMI feedback, as shown in Figure 1;

 In mode 1), Mri is configured, where Mri is a parameter indicating the configuration of the RI transmission period, and the CQI/PMI of the primary serving cell and the coordinated cell are fed back between the two feedback RIs. When the PCI needs to be fed back, the PCI may be fed back on an independent feedback period between the primary serving cell feedback CQI/PMI and the coordinated cell feedback CQI/PMI (see mode 1 in FIG. 1). In this extended mode, the Mri value of the high-level configuration needs to be greater than or equal to the period required by the primary serving cell and the coordinated cell wideband CQI/PMI and PCI feedback.

 In mode 2), the feedback of the PCI is placed on the same subframe as the feedback of the RI, and the CQI/PMI of the primary serving cell and other coordinated cells are fed back between the two feedback RI/PCI cycles (see FIG. 1). In the way 2). In this extended mode, the Mri value of the high-level configuration needs to be greater than the period required for the primary serving cell and the coordinated cell wideband CQI/PMI feedback.

In mode 1), when the feedback PCI is not required, the CQI/PMI information of the coordinated cell is fed back at the corresponding location. In addition, w _P represents the feedback period of CQI/PMI; the feedback period offset of RI refers to the offset of the feedback of RI with respect to CQI feedback, and the offset is 0 or a certain negative value.

 In the extended mode based on wideband CQI/PMI feedback, the period of two RI information feedback is M_ri* ( 1+Hc ) *Np (when PCI and RI are in the same time slot feedback) or M_ri* ( l+1+Hc ) *Np (PCI is in independent time slot feedback);

 2. Extension based on wideband CQI/PMI and subband CQI feedback, as shown in Figure 2; In mode 1), when feedback PCI is required, PCI feeds back on independent CQI feedback slots, and the feedback slot is Between the primary serving cell CSI information feedback and the coordinated cell CSI information feedback. The coordinated cell performs feedback on the CSI of the primary serving cell and the Np period of He after the PCI feedback. Where He corresponds to the number of coordinated cells that need to be fed back.

In mode 2, when feedback PCI is required, PCI and RI feed back in the same time slot. The cell performs feedback on the Np period of He after the CSI feedback of the primary serving cell. Where He corresponds to the number of coordinated cells that need to be fed back.

 Similarly, in Fig. 2, the figure shows the feedback period of CQI/PMI; the feedback period offset of RI refers to the offset of the feedback of RI with respect to CQI feedback, which is 0 or a certain negative value.

 Based on the wideband CQI/PMI and subband CQI feedback extension modes, the feedback methods in more specific different situations include:

 1) When the PCI needs to be fed back, and the RI and PCI are fed back in the same subframe, the CSI information of the primary serving cell and other coordinated cells is fed back in the subframe within the RI/PCI feedback interval. The feedback timing relationship at this time is: The feedback period of PCI and / or RI is M_ri * ( H + Hc ) * Np;

 2) When the PCI feeds back on the independent subframe, the CSI information of the primary serving cell and other coordinated cells is fed back in the subframe within the RI feedback interval. If feedback PCI is required, the feedback timing relationship at this time is: M_ri* ( H+1+Hc ) *Np of the feedback period of RI; if feedback PCI is not required, the feedback timing relationship at this time is: The feedback period of RI is M_ri * ( H+Hc ) *Np.

 Np represents the feedback period of the CQI; H represents the number of feedback cycles required to feed back the wideband CQI/PMI and subband CQI of the primary serving cell, H=J*K+1. Where J represents the number of specific bandwidths of the feedback CQI; K represents the number of CQIs fed back over a specific bandwidth; He represents the number of feedbacks required by other coordinated cells in the cooperative set except the primary serving cell; M_ri is positive Integer.

 When the UE uses the selective subband mode feedback for the primary serving cell and other coordinated cells, Hc=Nc*H, Nc indicates the number of other coordinated cells to be fed back, and He indicates that it needs to feed back other cell information outside the primary serving cell. The number of feedback cycles.

 Embodiment 2: PUSCH feedback extension

In LTE R8, the feedback on the CSI information on the PUSCH exists only in two cases. In one case, there is uplink shared data during periodic feedback. At this time, the CSI information is transmitted on the PUSCH, and the format and the feedback format on the PUCCH. the same. The other case is aperiodic feedback. When acyclic feedback is configured in the PDCCH, the aperiodic feedback mode pair configured according to the upper layer is used. The CSI information is fed back. Generally, aperiodic feedback is performed only in the following two cases: The DCI format of the downlink transmission is 0, and the CQI request in DCI format 0 is set to 1;

 When the corresponding authorized CQI request for random access is set to 1.

 When considering the extension of CoMP, the case where the CQI request in the downlink DCI format 0 is set to 1 is mainly considered. In practical applications, two modes of PUSCH feedback can be considered separately: mode 1), based on the aperiodic PUSCH feedback mode requested by the UE. The UE sends an uplink scheduling request and performs feedback according to the uplink authorization of the network side.

 Mode 2), based on the aperiodic PUSCH feedback configured on the network side, the minimum interval is lms. For the foregoing manners 1) and 2), the network side may also be configured periodically, or the UE periodically requests. In this case, it is degraded to periodic PUSCH feedback.

 When channel coding is performed, the feedback information of the primary serving cell and the feedback information of the coordinated cell may be jointly encoded, that is, the channel information (CQI/PMI) of the primary serving cell and other coordinated cells (CQI/PMI) and optional PCI. Co-channel coding is performed, and independent channel coding is performed separately from HARQ-ACK/NACK (Hybrid Automatic Repeat Request-Acknowledgment/Non-Acknowledgment) and RI. The HARQ-ACK, the channel information (CQI/PMI) of the RL primary serving cell, and the channel information of other coordinated cells may also be independently channel-encoded.

 Specifically, when the extension based on the wideband CQI feedback is performed, for each coordinated cell, the CQI and the PMI of the broadband can be calculated according to the same subband division manner as the primary serving cell, and the rank and the master corresponding to the calculation of the CQI/PMI can be calculated. The service area is the same.

When the UE selects the subband feedback extension, when the high layer configuration uses the feedback mode 2-0 (the UE selects the subband feedback and does not feed back the PMI), the UE only calculates the wideband CQI of the coordinated cell, and calculates the coordinated cell wideband CQI. The CQI may be calculated based solely on codeword stream 1 or 2 CQIs based on different codeword streams, respectively. And, the difference between the broadband CQI and the primary serving cell can be fed back. Score.

 In addition, when the high layer configuration uses the feedback mode 2-2 (the UE selects the subband feedback and feeds back the PMI), the UE may calculate only one wideband PMI and the wideband CQI, and the wideband CQI may be based on the codeword stream 1 or based on each Each codeword stream is calculated separately.

 When the high-layer configuration is used for the sub-band feedback extension, when the high-layer configuration uses the feedback mode 3-0 (the high-level configuration sub-band feedback and does not feed back the PMI), the UE may only calculate the broadband CQI of the coordinated cell, and the operation mode is as described above. The 2-0 is similar; for the calculation of the coordinated cell wideband CQI, the CQI can be calculated based on only the codeword stream 1 or calculated on a per codeword stream basis. And, the difference value with the broadband CQI of the primary serving cell can be fed back.

 In addition, when the high layer configuration uses feedback mode 3-1 (high-level configuration sub-band feedback and feedback PMI), the UE may calculate only one wideband PMI and wideband CQI, and the wideband CQI may be based on codeword stream 1 or based on each Each codeword stream is calculated separately.

 It can be seen that the operation of the channel information feedback in the CoMP mode of the present invention can be represented as shown in FIG. 3 . Referring to FIG. 3, FIG. 3 is a flowchart of channel information feedback in a CoMP mode according to an embodiment of the present invention, where the process includes the following steps:

 Step 310: Differentiate the primary serving cell and other coordinated cells outside the primary serving cell in the coordinated multi-point transmission mode.

 Step 320: The terminal performs channel information feedback on the primary serving cell and other coordinated cells outside the primary serving cell according to respective feedback modes and/or different granularities.

 In order to ensure that the above technical content can be smoothly implemented, the settings shown in FIG. 4 can be performed. Referring to FIG. 4, FIG. 4 is a system diagram of channel information feedback in CoMP mode according to an embodiment of the present invention, where the system includes a feedback distinguishing unit and a primary serving cell feedback unit and a coordinated cell feedback unit connected thereto, and the foregoing units may be configured on The UE or the like is used in a functional entity for performing channel information feedback.

In actual application, the feedback distinguishing unit can confirm that the current multi-point coordinated transmission mode is present, and notify the primary serving cell feedback unit and the coordinated cell feedback unit of the situation; The feed unit and the coordinated cell feedback unit distinguish the primary serving cell from other coordinated cells outside the primary serving cell, and respectively perform channels on the primary serving cell and other coordinated cells outside the primary serving cell according to respective feedback modes and/or different granularities. information feedback. The primary serving cell refers to: a cell that sends physical downlink control information to the user; the coordinated cell refers to: one or more cells that need to measure and feed back channel state information.

 It should be noted that, when the primary serving cell feedback unit feeds back to the primary serving cell, any one or more feedback modes supported in a transmission mode following a single cell closed-loop spatial multiplexing: periodic broadband CQI /PMI feedback, periodic wideband CQI/PMI+ subband CQI feedback mode, aperiodic wideband feedback mode, aperiodic UE selection subband feedback mode or aperiodic high layer configuration subband feedback mode.

 When the coordinated cell feedback unit uses the respective mode feedback for the other coordinated cells outside the primary serving cell, it is used to: when the CSI information of other cells other than the primary serving cell is fed back, the mode of the wideband CQI/PMI is used.

 When the coordinated cell feedback unit uses different granularity feedback for other coordinated cells outside the primary serving cell, it is used to: use a codebook set smaller than the primary serving cell for the coordinated cell other than the primary serving cell and/or Or a smaller set of channel quality indications.

 When the primary serving cell feedback unit and the coordinated cell feedback unit are fed back, each of the cells corresponding to the primary serving cell is used to: feed back CSI information of other coordinated cells outside the primary serving cell on a channel different from the primary serving cell; The CSI information of the primary serving cell is fed back on any one of the feedback channels used in the single cell closed-loop spatial multiplexing transmission mode; and the other coordinated cells are periodically reported on the physical uplink shared channel;

 Alternatively, the CSI information of other coordinated cells outside the primary serving cell is fed back in a different time slot from the primary serving cell.

The coordinated cell feedback unit is further configured to: feed back a differential CQI for each cell for all or part of the coordinated cells outside the primary serving cell in the coordinated set; In the case where there are multiple data streams (layers), the CQI that feeds back the difference for each cell means: each data stream is differentially fed back to the wideband CQI of the primary serving cell.

 For the CSI information of the other coordinated cells outside the primary serving cell, when the primary serving cell feedback unit and the coordinated cell feedback unit perform feedback on a different time slot from the primary serving cell, the following sequence is used for each corresponding cell. Relationship: First, the channel information of the primary serving cell is fed back, and the channel information of all or part of the coordinated cells is respectively fed back on the subsequent feedback time slots.

 If feedback is performed on the PUCCH and feedback phase correction PCI information is required, the feedback period of the PCI is the same as the rank information RI feedback period or an integer multiple of the RI feedback period.

 When the feedback is performed by the primary serving cell feedback unit and the coordinated cell feedback unit for the corresponding cell, the one or the following ones are used in the process of implementing the timing relationship of the PCI feedback:

 a) if the RI and the PCI are fed back in the same subframe, the CSI information of each cell in the cooperation set is fed back in the subframe within the RI/PCI feedback interval; the feedback timing relationship at this time is: PCI or RI The feedback period is M_ri* ( H+Hc ) *Np;

 b) feeding back the CSI information feedback of each cell in the cooperation set on different time slots in the RI feedback interval if the PCI performs feedback on a separate subframe; wherein the cooperation The CSI information of each cell in the set includes PCI information; the feedback timing relationship is: the feedback period of the RI is M_ri* ( H+1+Hc ) *Np;

 The Np represents a CQI/PMI feedback period; the value of the H is different in different feedback modes;

 When the primary serving cell is based on broadband feedback, H=l;

When the sub-band mode feedback is selected for the primary serving cell and the broadband feedback mode is used for other cells, H=J*K+1; where J represents the number of reserved bandwidths of the feedback CQI; K represents feedback on the reserved bandwidth. Number of CQIs, He indicates feedback of other coordinated cells in the cooperative set except the primary serving cell The number of time slots required at the time, where He is equal to the number of other coordinated cells;

 When the primary sub-band mode feedback is used for the primary serving cell and other coordinated cells,

Hc=Nc*H; Nc represents the number of other coordinated cells to be fed back;

 M_ri is a positive integer;

 c) If feedback is performed on the PUCCH and there is no need to feed back PCI, the feedback timing relationship at this time is: The feedback period of the RI is M_ri* ( H+Hc ) *Np , between the slots of the two feedback RIs, The feedback is performed on the feedback subframe after the CSI information of the primary serving cell is fed back.

 The primary serving cell feedback unit is further configured to: when the PCI information needs to be fed back, and the PCI feeds back on the independent time slot, the CSI information of the PCI in the primary serving cell is fed back to other cell CSI information outside the primary serving cell. Feedback is made on the time slot between the feedbacks.

 In summary, the method for implementing channel information feedback in CoMP mode can support channel information feedback in CoMP mode, and can dynamically support single-cell CSI information feedback and multi-cell. Feedback of CSI information, which can adapt to dynamic switching between different transmission technologies.

 The above description is only for the preferred embodiment of the present invention, and is not intended to limit the scope of the present invention. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present invention should be included. Within the scope of protection of the present invention.

Claims

Claim  A method for channel information feedback in a CoMP multipoint coordinated transmission mode, the method comprising: in a coordinated multi-point transmission mode, the terminal according to a respective feedback mode of the primary serving cell and other coordinated cells outside the primary serving cell and/or Or channel information feedback at different granularities;  The primary serving cell refers to: a cell that sends physical downlink control information to the user; the coordinated cell refers to: one or more cells that need to measure and feed back channel state information.  2. The method according to claim 1, wherein  The feedback to the primary serving cell follows any one or more feedback modes supported in a single cell closed-loop spatial multiplexing transmission mode:  The periodic wideband channel quality indicator CQI/precoding matrix indicates PMI feedback, periodic wideband CQI/PMI+subband CQI feedback mode, aperiodic wideband feedback mode, aperiodic user equipment UE selects subband feedback mode or aperiodic The feedback mode of the sub-band of the high-level configuration.  3. The method according to claim 1, wherein  The respective mode refers to the other coordinated cells outside the primary serving cell: the channel state information of other cells outside the primary service cell is fed back, and the mode of the wideband CQI/PMI is used;  Different granularity feedback is used for other coordinated cells outside the primary serving cell: a smaller codebook set and/or a smaller channel quality indicator set than the primary serving cell is used for the coordinated cell other than the primary serving cell.  4. The method according to claim 3, wherein  The CSI information of the other coordinated cells outside the primary serving cell is fed back on a different channel from the primary serving cell; the CSI information of the primary serving cell is used in the transmission mode of the single cell closed-loop spatial multiplexing a feedback on the feedback channel; performing periodic reporting on the physical uplink shared channel for the other coordinated cells; Or, the CSI information of other coordinated cells outside the primary serving cell is in the primary serving cell Feedback is performed on different time slots.  5. The method according to claim 1, wherein the method further comprises:  For all or part of the coordinated cells outside the primary serving cell in the cooperative set, a differential CQI is fed back for each cell;  In the case where there are multiple data streams (layers), the CQI that feeds back the difference for each cell means: each data stream is differentially fed back to the wideband CQI of the primary serving cell.  6. The method according to claim 4, wherein  The timing relationship when the CSI information of other coordinated cells outside the primary serving cell is fed back in a different time slot from the primary serving cell is:  First, the channel information of the primary serving cell is fed back, and the channel information of all or part of the coordinated cells is respectively fed back on the subsequent feedback time slots.  7. The method according to claim 1, wherein the method further comprises:  When it is required to feed back the PCI between different nodes, and the channel information of other cells is fed back on the physical uplink shared channel PUSCH, the PCI information and the channel information of other cells are fed back in the same subframe;  When the channel information of other cells is fed back on the PUCCH, the PCI information is fed back on a specific independent subframe, or is fed back in the same subframe as the RI.  8. The method according to claim 6 or 7, wherein, if feedback is performed on the PUCCH and feedback phase correction PCI information is required, the feedback period of the PCI is the same as the rank information RI feedback period or an integer multiple of the RI feedback period.  9. The method according to claim 8, wherein the timing relationship of the PCI feedback is any one or more of the following: a) if the RI and the PCI are fed back in the same subframe, the CSI information of each cell in the cooperation set is fed back in the subframe within the RI/PCI feedback interval; the feedback timing relationship at this time is: PCI or RI The feedback period is M_ri* ( H+Hc ) *Np; b) feeding back the CSI information feedback of each cell in the cooperation set on different time slots in the RI feedback interval if the PCI performs feedback on a separate subframe; wherein the cooperation The CSI information of each cell in the set includes PCI information; the feedback timing relationship is: the feedback period of the RI is M_ri* ( H+1+Hc ) *Np;  The Np represents a CQI/PMI feedback period; the value of the H is different in different feedback modes;  When the primary serving cell is based on broadband feedback, H=l;  When the sub-band mode feedback is selected for the primary serving cell and the broadband feedback mode is used for other cells, H=J*K+1; where J represents the number of reserved bandwidths of the feedback CQI; K represents feedback on the reserved bandwidth. The number of CQIs, He indicates the number of slots required for feedback from other coordinated cells in the coordinated set except the primary serving cell, where He is equal to the number of other coordinated cells;  When the primary sub-band mode feedback is used for the primary serving cell and other coordinated cells, Hc=Nc*H; Nc represents the number of other coordinated cells to be fed back;  M_ri is a positive integer;  c) If feedback is performed on the PUCCH and there is no need to feed back PCI, the feedback timing relationship at this time is: The feedback period of the RI is M_ri* ( H+Hc ) *Np , between the slots of the two feedback RIs, The feedback is performed on the feedback subframe after the CSI information of the primary serving cell is fed back.  10. The method according to claim 9, wherein  When the PCI information needs to be fed back, and the PCI feeds back on the independent time slot, the PCI feeds back on the time slot between the primary serving cell CSI information feedback and other cell CSI information feedback outside the primary serving cell.  A system for channel information feedback in a CoMP mode, the system comprising a feedback distinguishing unit, a primary serving cell feedback unit, and a coordinated cell feedback unit; The feedback distinguishing unit is configured to confirm that the current multi-point coordinated transmission mode is present, and notify the primary serving cell feedback unit and the coordinated cell feedback unit of the situation; The primary serving cell feedback unit and the coordinated cell feedback unit are configured to distinguish the primary serving cell from other coordinated cells outside the primary serving cell, and respectively perform the respective feedback modes for the primary serving cell and other coordinated cells outside the primary serving cell. And/or different granularity for channel information feedback; wherein, the primary serving cell refers to: a cell that sends physical downlink control information to the user; the coordinated cell refers to: one or more cells that need to measure and feed back channel state information. .  12. The system of claim 11 wherein  When the primary serving cell feedback unit feeds back to the primary serving cell, it is used to follow any one or more feedback modes supported in a single-cell closed-loop spatial multiplexing transmission mode:  Periodic wideband CQI/PMI feedback, periodic wideband CQI/PMI+ subband CQI feedback mode, aperiodic wideband feedback mode, aperiodic UE selection subband feedback mode or aperiodic high layer configuration subband feedback mode.  13. The system according to claim 12, wherein  When the coordinated cell feedback unit uses the respective mode feedback for the other coordinated cells outside the primary serving cell, the method is: when the CSI information of other cells other than the primary serving cell is fed back, the mode of the broadband CQI/PMI is used;  When the coordinated cell feedback unit uses different granularity feedback for other coordinated cells outside the primary serving cell, it is used to: use a codebook set smaller than the primary serving cell for the coordinated cell other than the primary serving cell and/or Or a smaller set of channel quality indications.  The system according to claim 13, wherein, when the feedback is performed, the primary serving cell feedback unit and the coordinated cell feedback unit are used for:  The CSI information of the other coordinated cells outside the primary serving cell is fed back on a different channel from the primary serving cell; the CSI information of the primary serving cell is used in the transmission mode of the single cell closed-loop spatial multiplexing a feedback on the feedback channel; performing periodic reporting on the physical uplink shared channel for the other coordinated cells; Or, the CSI information of other coordinated cells outside the primary serving cell is in the primary serving cell Feedback is performed on different time slots.  The system according to claim 12, wherein the coordinated cell feedback unit is further configured to:  For all or part of the coordinated cells outside the primary serving cell in the cooperative set, a differential CQI is fed back for each cell;  In the case where there are multiple data streams (layers), the CQI that feeds back the difference for each cell means: each data stream is differentially fed back to the wideband CQI of the primary serving cell.  16. The system according to claim 14, wherein, for CSI information of other coordinated cells outside the primary serving cell, the primary serving cell feedback unit and the coordinated cell feedback unit perform feedback on a different time slot from the primary serving cell. When used, the cells for their respective cells follow the following timing relationship:  First, the channel information of the primary serving cell is fed back, and the channel information of all or part of the coordinated cells is respectively fed back on the subsequent feedback time slots.  The system of claim 16, wherein if feedback is performed on the PUCCH and feedback phase correction PCI information is required, the feedback period of the PCI is the same as the rank information RI feedback period or an integer multiple of the RI feedback period.  The system according to claim 17, wherein, when the primary serving cell feedback unit and the coordinated cell feedback unit perform the feedback for the cell corresponding to the UE, the method for implementing the timing relationship of the PCI feedback is used. Apply one or more of the following:  a) if the RI and the PCI are fed back in the same subframe, the CSI information of each cell in the cooperation set is fed back in the subframe within the RI/PCI feedback interval; the feedback timing relationship at this time is: PCI or RI The feedback period is M_ri* ( H+Hc ) *Np; b) feeding back the CSI information feedback of each cell in the cooperation set on different time slots in the RI feedback interval if the PCI performs feedback on a separate subframe; wherein the cooperation The CSI information of each cell in the set includes PCI information; feedback timing The relationship is: The feedback period of RI is M_ri* ( H+1+Hc ) *Np;  The Np represents a CQI/PMI feedback period; the value of the H is different in different feedback modes;  When the primary serving cell is based on broadband feedback, H=l;  When the sub-band mode feedback is selected for the primary serving cell and the broadband feedback mode is used for other cells, H=J*K+1; where J represents the number of reserved bandwidths of the feedback CQI; K represents feedback on the reserved bandwidth. The number of CQIs, He indicates the number of slots required for feedback from other coordinated cells in the coordinated set except the primary serving cell, where He is equal to the number of other coordinated cells;  When the primary sub-band mode feedback is used for the primary serving cell and other coordinated cells, Hc=Nc*H; Nc represents the number of other coordinated cells to be fed back;  M_ri is a positive integer;  c) If feedback is performed on the PUCCH and there is no need to feed back PCI, the feedback timing relationship at this time is: The feedback period of the RI is M_ri* ( H+Hc ) *Np , between the slots of the two feedback RIs, The feedback is performed on the feedback subframe after the CSI information of the primary serving cell is fed back.  The system according to claim 18, wherein the primary serving cell feedback unit is further configured to:  When the PCI information needs to be fed back, and the PCI feeds back on the independent time slot, the PCI feeds back on the time slot between the primary serving cell CSI information feedback and other cell CSI information feedback outside the primary serving cell.