Method and device for transmitting CSI feedback message

Abstract

The invention relates to a method and apparatus for transmitting a channel state information (CSI) feedback message. An embodiment of the present disclosure provides a user equipment (UE) comprising: a transceiver configured to receive a channel state information reference signal (CSI-RS) report configuration message indicating a plurality of CSI-RS resources for channel measurement and at least one zero-power or non-zero-power CSI-RS resources for interference measurement, wherein each CSI-RS resource in the plurality of CSI-RS resources is associated with a CSI-RS resource indicator (CRI) and a same number of CSI-RS ports; and a processor coupled with the transceiver and configured to: perform a channel measurement procedure based on the CSI report configuration message; and selecting a set of CSI-RS resources from the plurality of CSI-RS resources for joint transmission based on the channel measurement procedure; wherein the transceiver is further configured to transmit a CSI feedback message after performing the channel measurement procedure, where the CSI feedback message includes a single rank indicator (RI), a single channel quality indicator (CQI), and a set of precoding matrix indicators (PMIs), where each PMI in the set of PMIs is associated with a respective CSI-RS resource in the selected set of CSI-RS resources, and wherein the RI indicates a rank applied to each CSI-RS resource in the selected set of CSI-RS resources, and the CQI indicates a channel quality associated with all CSI-RS resources in the selected set of CSI-RS resources.

Description

Technical Field

[0001] The present disclosure relates to wireless communications, and in particular, to methods and apparatus for transmitting channel state information (CSI) feedback messages. Background Art

[0002] The continued evolution of Multiple Input Multiple Output (MIMO) may be the most important part of the 3rd Generation Partnership Project (3GPP) physical layer. It is important to identify and specify the necessary enhancements for both downlink and uplink MIMO to facilitate the use of large antenna arrays, not only for frequency range 1 (FR1) but also for FR2 to meet the evolving requirements of New Radio (NR) deployments in Rel-18.

[0003] Enhancements to CSI acquisition for frequency division duplex (FDD) and time division duplex (TDD) for FR1 can be beneficial in extending the utility of multiple transmit or receive point (TRP) deployments, since coherent joint transmission (CJT) uses high-performance backhaul and synchronization to improve coverage and average throughput in commercial deployments.

[0004] It would therefore be advantageous to provide improved methods and apparatus for transmitting CSI feedback messages. Summary of the invention

[0005] Some embodiments of the present disclosure provide a user equipment (UE), comprising: a transceiver, which is configured to: receive a CSI report configuration message indicating a plurality of channel state information reference signal (CSI-RS) resources for channel measurement and at least one zero power or non-zero power CSI-RS resource for interference measurement, wherein each CSI-RS resource in the plurality of CSI-RS resources is associated with a CSI-RS resource indicator (CRI) and the same number of CSI-RS ports; and a processor, which is coupled to the transceiver and is configured to: perform a channel measurement procedure based on the CSI report configuration message; and select a CSI-RS resource from the plurality of CSI-RS resources based on the channel measurement procedure. Selecting a CSI-RS resource set for joint transmission; wherein the transceiver is further configured to: transmit a CSI feedback message after performing the channel measurement procedure, wherein the CSI feedback message includes a single rank indicator (RI), a single channel quality indicator (CQI) and a precoding matrix indicator (PMI) set, wherein each PMI in the PMI set is associated with a corresponding CSI-RS resource in the selected CSI-RS resource set, and wherein the RI indicates a rank applied to each CSI-RS resource in the selected CSI-RS resource set, and the CQI indicates a channel quality associated with all CSI-RS resources in the selected CSI-RS resource set.

[0006] In some embodiments, each PMI in the PMI set is based on an eType 2 codebook and includes the phase of the strongest frequency domain component of each data layer.

[0007] In some embodiments, each PMI in the PMI set incorporates a number of phase adjustment factors, the total number of the phase adjustment factors is equal to the value of the RI, and each phase adjustment factor is associated with a data layer of the corresponding CSI-RS resource.

[0008] In some embodiments, each phase adjustment factor is associated with all subbands.

[0009] In some embodiments, each phase adjustment factor is associated with a respective subband.

[0010] In some embodiments, each PMI in the PMI set is based on an eType 2 codebook and includes a plurality of phase adjustment factors, the total number of the phase adjustment factors is equal to the value of the RI, and each phase adjustment factor is associated with a data layer of the corresponding CSI-RS resource.

[0011] In some embodiments, each phase adjustment factor is associated with a respective subband.

[0012] In some embodiments, each phase adjustment factor is associated with all subbands.

[0013] In some embodiments, each PMI in the PMI set includes an amplitude adjustment factor for a codeword associated with the corresponding CSI-RS resource.

[0014] Some other embodiments of the present disclosure provide a base station (BS), comprising: a transceiver, which is configured to: transmit a CSI report configuration message indicating multiple CSI-RS resources for channel measurement and at least one zero power or non-zero power CSI-RS resource for interference measurement, wherein each CSI-RS resource in the multiple CSI-RS resources is associated with a CRI and the same number of CSI-RS ports; and receive a CSI feedback message including a single RI, a single CQI and a PMI set, wherein each PMI in the PMI set is associated with a corresponding CSI-RS resource in a subset of the multiple CSI-RS resources, and wherein the RI indicates a rank applied to each CSI-RS resource in the subset of the multiple CSI-RS resources, and the CQI indicates a channel quality associated with all CSI-RS resources in the subset of the multiple CSI-RS resources; and a processor, which is coupled to the transceiver.

[0015] In some embodiments, each PMI in the PMI set is based on an eType 2 codebook and includes the phase of the strongest frequency domain component of each data layer.

[0016] In some embodiments, each PMI in the PMI set incorporates a number of phase adjustment factors, the total number of the phase adjustment factors is equal to the value of the RI, and each phase adjustment factor is associated with a data layer of the corresponding CSI-RS resource.

[0017] In some embodiments, each phase adjustment factor is associated with all subbands.

[0018] In some embodiments, each phase adjustment factor is associated with a respective subband.

[0019] In some embodiments, each PMI in the PMI set is based on an eType 2 codebook and includes a plurality of phase adjustment factors, the total number of the phase adjustment factors is equal to the value of the RI, and each phase adjustment factor is associated with a data layer of the corresponding CSI-RS resource.

[0020] In some embodiments, each phase adjustment factor is associated with a respective subband.

[0021] In some embodiments, each phase adjustment factor is associated with all subbands.

[0022] In some embodiments, each PMI in the PMI set includes an amplitude adjustment factor for a codeword associated with the corresponding CSI-RS resource.

[0023] Some other embodiments of the present disclosure provide a method performed by a UE, comprising: receiving a CSI report configuration message indicating multiple CSI-RS resources for channel measurement and at least one zero power or non-zero power CSI-RS resource for interference measurement, wherein each of the multiple CSI-RS resources is associated with a CRI and the same number of CSI-RS ports; performing a channel measurement procedure based on the CSI report configuration message; selecting a CSI-RS resource set from the multiple CSI-RS resources for joint transmission based on the channel measurement procedure; and transmitting a CSI feedback message after performing the channel measurement procedure, wherein the CSI feedback message includes a single RI, a single CQI and a PMI set, wherein each PMI in the PMI set is associated with a corresponding CSI-RS resource in the selected CSI-RS resource set, and wherein the RI indicates a rank applied to each CSI-RS resource in the selected CSI-RS resource set, and the CQI indicates a channel quality associated with all CSI-RS resources in the selected CSI-RS resource set.

[0024] Some other embodiments of the present disclosure provide a method performed by a BS, comprising: transmitting a CSI report configuration message indicating multiple CSI-RS resources for channel measurement and at least one zero power or non-zero power CSI-RS resource for interference measurement, wherein each CSI-RS resource in the multiple CSI-RS resources is associated with a CRI and the same number of CSI-RS ports; and receiving a CSI feedback message including a single RI, a single CQI, and a PMI set, wherein each PMI in the PMI set is associated with a corresponding CSI-RS resource in a subset of the multiple CSI-RS resources, and wherein the RI indicates a rank applied to each CSI-RS resource in the subset of the multiple CSI-RS resources, and the CQI indicates a channel quality associated with all CSI-RS resources in the subset of the multiple CSI-RS resources. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] In order to describe the manner in which the advantages and features of the present application can be obtained, the description of the present application is presented by reference to specific embodiments of the present application illustrated in the accompanying drawings. These drawings depict only example embodiments of the present application and therefore should not be considered as limiting the scope thereof.

[0026] Figure 1 A schematic diagram illustrating an exemplary wireless communication system according to some embodiments of the present disclosure.

[0027] Figure 2 A flow chart illustrating an exemplary method performed by a UE for transmitting CSI feedback information according to some embodiments of the present disclosure.

[0028] Figure 3 A method performed by a BS according to some embodiments of the present disclosure is described.

[0029] Figure 4 A simplified block diagram illustrating an exemplary apparatus according to some embodiments of the present disclosure. DETAILED DESCRIPTION

[0030] The detailed description of the accompanying drawings is intended as a description of the currently preferred embodiments of the present invention and is not intended to represent the only form in which the present invention can be practiced. It should be understood that the same or equivalent functions can be accomplished by different embodiments that are intended to be included in the spirit and scope of the present invention.

[0031] Although the operations are depicted in a particular order in the drawings, those skilled in the art will readily recognize that such operations need not be performed in the particular order as shown or in sequential order, or that all of the illustrated operations need not be performed to achieve a desired result; one or more operations may sometimes be skipped. In addition, the drawings may schematically depict one or more example processes in the form of a flow chart. However, other operations not depicted may be incorporated into the schematically illustrated example processes. For example, one or more additional operations may be performed before, after, simultaneously with, or between any of the illustrated operations. In some cases, multitasking and parallel processing may be advantageous.

[0032] Reference will now be made in detail to some embodiments of the present disclosure, examples of which are illustrated in the accompanying drawings. To facilitate understanding, embodiments are provided under specific network architectures and new service scenarios (e.g., 3GPP Long Term Evolution (LTE), Advanced LTE (LTE-A), 3GPP 4G, 3GPP 5G NR, 3GPP Release 16 and higher, etc.). With due consideration, all embodiments in the present disclosure are also applicable to similar technical issues as network architectures and new service scenarios evolve; and in addition, the terms cited in the present disclosure may be changed, which should not affect the principles of the present disclosure.

[0033] Figure 1 is a schematic diagram illustrating an exemplary wireless communication system according to some embodiments of the present application.

[0034] refer to Figure 1 , the wireless communication system may include BS101, several TRPs (e.g., TRP 103-1, TRP 103-2, ..., TRP 103-N) and UE 105. Although only one BS101, three TRPs and one UE 105 are shown for the sake of brevity, it should be noted that according to some other embodiments of the present application, the wireless communication system may include more or fewer communication devices, apparatuses or nodes.

[0035] The wireless communication system is compatible with any type of network capable of sending and receiving wireless communication signals. For example, the wireless communication system is compatible with wireless communication networks, cellular telephone networks, networks based on time division multiple access (TDMA), networks based on code division multiple access (CDMA), networks based on orthogonal frequency division multiple access (OFDMA), LTE networks, networks based on 3GPP, 3GPP 5G networks, satellite communication networks, high altitude platform networks, and / or other communication networks.

[0036] BS 101 may also be referred to as an access point, access terminal, base, macro cell, Node B, enhanced Node B (eNB), gNB, home Node B, relay node or device, or described using other terms used in the art. BS 101 is typically part of a radio access network that may include a controller communicatively coupled to BS 101.

[0037] The TRP may communicate with BS 101 via, for example, a backhaul link. Each TRP may serve one or more UEs. Figure 1 As shown in FIG. 1 , TRP 103-1 may serve some mobile stations (including UE 105) within a service area or region (e.g., a cell or cell sector), TRP 103-2 may serve some mobile stations (including UE 105) within a service area or region (e.g., a cell or cell sector), and TRP 103-N may serve some mobile stations (including UE 105) within a service area or region (e.g., a cell or cell sector). In some embodiments, TRP 103-1, TRP 103-2, and TRP 103-N may serve different UEs. The TRPs may be connected to each other via, for example, a backhaul link ( Figure 1 (not shown) communicate with each other.

[0038] UE 105 may include a computing device, such as a desktop computer, a laptop computer, a personal digital assistant (PDA), a tablet computer, a smart TV (such as a TV connected to the Internet), a set-top box, a game console, a security system (including a security camera), a car computer, a network device (such as a router, a switch and a modem), etc. According to some embodiments of the present disclosure, UE 105 may include a portable wireless communication device, a smart phone, a cellular phone, a flip phone, a device with a subscriber identity module, a personal computer, a selective call receiver, or any other device capable of sending and receiving communication signals on a wireless network. In some embodiments of the present disclosure, UE 105 may include a wearable device, such as a smart watch, a fitness bracelet, an optical head-mounted display, etc. In addition, UE 105 may be referred to as a subscriber unit, a mobile device, a mobile station, a user, a terminal, a mobile terminal, a wireless terminal, a fixed terminal, a subscriber station, a user terminal or a device, or described using other terms used in the art.

[0039] In some embodiments of the present application, TRPs (e.g., TRP 103-1, TRP 103-2, ..., TRP 103-N) may perform CJT with UE 105. All TRPs involved in CJT may have the same antenna configuration but at different locations. Therefore, the channels from these TRPs to UE 105 are independent, which can be represented as a matrix: H = [H1H2 ...H N], where the channel from TRP 103-1 to UE 105 can be represented as a vector: H1, the channel from TRP 103-2 to UE 105 can be represented as a vector: H2, ..., and the channel from TRP 103-N to UE 105 can be represented as a vector: H N .

[0040] Each TRP can be configured and transmitted using CSI-RS resources to use the same number of antenna ports for channel measurement. In addition, in CJT, each TRP can transmit the same data to UE 105.

[0041] The UE 105 may receive a CSI report configuration message (e.g., CSI-reportConfig), for example, via radio resource control (RRC) signaling. The CSI report configuration message may indicate CSI-RS resources used for channel measurement, each CSI-RS resource corresponding to a respective TRP. The number of CSI-RS resources used for channel measurement may be based on the capabilities reported by the UE 105. The CSI report configuration message may also include at least one zero power or non-zero power CSI-RS resource for interference measurement.

[0042] After receiving the CSI report configuration message, UE 105 may perform a channel measurement procedure based on the information included in the CSI report configuration message. In particular, UE 105 may perform a channel measurement procedure for all configured CSI-RS to perform channel measurement. After the measurement, UE 105 may then select a CSI-RS resource set from the CSI-RS resources for joint transmission based on the channel measurement procedure. UE 105 may select a CSI-RS resource set based on UE capabilities or a configuration from the network (e.g., from BS 101), or both. UE 105 may indicate the selected CSI-RS resource set in a CSI feedback message transmitted to the network. In other words, UE 105 may indicate to the network the selected TRP corresponding to the selected CSI-RS resource set, and the selected TRP may be used to perform CJT with UE 105.

[0043] The CSI feedback message may include the following information:

[0044] - Single RI;

[0045] - Single CQI; and

[0046] - One or more PMIs, wherein each PMI is associated with a CSI-RS resource in a selected CSI-RS resource set of the same rank as indicated by the RI.

[0047] A single RI may indicate the rank applied to each CSI-RS resource in the selected CSI-RS resource set, and a single CQI may indicate the channel quality associated with all CSI-RS resources in the selected CSI-RS resource set.

[0048] The present disclosure proposes that the precoding matrix for each TRP may be indicated by a PMI based on an eType 2 codebook with additional parameters to reflect different phases and / or different amplitudes between selected TRPs. Each physical uplink shared control channel (PUSCH) layer may be transmitted by all CSI-RS ports of all selected TRPs.

[0049] Assume that the signal transmitted by each of the N TRPs to the UE can be represented as "x", the channel matrix can be represented as "H", and the precoding matrix can be represented as "W". The individual channel from TRP n (1≤n≤N) can be represented as H n , and the individual precoder from TRP n can be expressed as W n For example, as specified in 3GPP documents (e.g., TS 38.214) It can be a description of a channel with selected CSI-RS resources (or selected beams) in the spatial domain and frequency / time domain for transmission with a rank value of R (which can be indicated by RI), and the detailed definition of each term in this expression can be found in the 3GPP documents and is omitted here for brevity.

[0050] For CJT, N TRPs may be geographically separated, and the channels from the N TRPs to the same UE are independent. The present disclosure proposes applying an amplitude adjustment factor or a data layer specific phase adjustment factor or both for each TRP. According to some embodiments, the present disclosure proposes the following precoding matrix:

[0051]

[0052] Among them, a n is the amplitude adjustment factor of TRP n, and in is the phase adjustment factor of data layer l (1≤l≤R) of TRP n. Then, the signal received at the UE can be expressed as:

[0053]

[0054] Based on H from TRP n estimated according to the corresponding CSI-RS resource n , UE can determine the W of TRP n n And the corresponding amplitude adjustment factor a n .set up

[0055] In the spatial domain, the vector are mutually orthogonal, so the UE can detect them without mutual interference. It then follows

[0056]

[0057] The optimization of the phase adjustment factor q can be performed for each data layer r individually as follows:

[0058]

[0059] Using the eType2 codebook, the rank-R PMI of each TRP is transmitted to the network in the form of two indices (i1, i2) (eg, as defined in TS38.214), and the network can reconstruct the precoders for several subbands from the PMI.

[0060] As shown in Table 5.2.2.2.5-5 in TS 38.214, for example, the precoder has a subscript t representing the subband index. In other words, the precoder is a function of frequency (or a function of the subband index t). Therefore, the optimal phase adjustment factor q n It can also be a function of frequency (or a function of subband index t). The present disclosure proposes a method for incorporating or including the optimal phase adjustment factor q in the PMI. n And send the optimal phase adjustment factor q to the network in the CSI response message n The three solutions are as follows.

[0061] Solution 1:

[0062] In solution 1, the UE may determine the phase adjustment factor matrix Q associated with all subbands n ,For example in is the phase adjustment factor of data layer l from TRP n, the value of "l" ranges from 1 to R, and R is the rank indicated by RI, which may range from 1 to 4 in some embodiments. In other words, is the phase adjustment factor associated with data layer l of the corresponding CSI-RS resource, which corresponds to TRP n.

[0063] In some embodiments, the UE may determine the matrix Q based on the UE's implementation n The matrix Q n It can be well applied to all subbands and the UE can incorporate it into the PMI to be reported to the network. It should be noted that the phase adjustment factor can be in other forms. For example, the UE can determine a set of phase adjustment factors, where the set includes Or the UE may determine several phase adjustment factors, the first of which is The second is ..., the Rth one is

[0064] According to some embodiments, the PMI of TRP n without incorporating the phase adjustment factor associated with TRP n may be reported as follows.

[0065] The key components of PMI as shown in Table 5.2.2.2.5-5 of TS 38.214 are:

[0066]

[0067] Among them, from i1 to q1, q2, n1, n2, n 3,1 、n 3,2 、n 3,3 、n 3,4 and from i2 to i 2,5,1 、i 2,5,2 、i 2,5,3 、i 2,5,4 , as well as and The mapping of is described in 3GPP documents (eg, TS 38.214), including the range of constituent indices of i1 and i2.

[0068] For example, the PMI value corresponds to the codebook index of i1 and i2, where

[0069]

[0070] From L+M v The vector determines the precoding matrix indicated by the PMI.

[0071] L vectors (i.e., ) is identified by indexes q1, q2, n1, n2, and by i 1,1 、i 1,2 Indication, as obtained in section 5.2.2.2.3 of TS 38.214, where the value of C(x,y) is given in Table 5.2.2.2.5-4 in TS 38.214.

[0072] vector, By M initial (for N3>19) and n 3,l (l=1,…,v) identification, where

[0073] M initial ∈{-2M v +1,-2M v +2,…,0}

[0074]

[0075] It is indexed by i 1,5 (for N3>19) and i 1,6,l (For M v >1 and l=1,…,v) indicates that

[0076] i 1,5 ∈{0,1,…,2M v -1}

[0077]

[0078] Amplitude factor indicator i 2,3,l andi 2,4,l yes

[0079]

[0080]

[0081] For l=1,…,v.

[0082] Phase coefficient indicator i 2,5,l yes

[0083] i 2,5,l =[c l,0 …c l,Mv-1 ]

[0084] c l,f =[c l,0,f …c l,2L-1,f ]

[0085] c l,i,f ∈{0,…,15}

[0086] For l=1,…,v.

[0087] set up Its non-zero position identification report i 2,4,l andi 2,5,l Which coefficients in the bitmap are represented by i 1,7,l instruct:

[0088]

[0089] For l = 1,…,v, such that is the number of non-zero coefficients of layer l=1,…,v, and is the total number of nonzero coefficients.

[0090] i 2,4,l 、i 2,5,l andi 1,7,l The index and n 3,l Mv The codebook index is associated.

[0091] from To the amplitude factor The mapping is given in Table 5.2.2.2.5-2 (reproduced below) and is obtained from To the amplitude factor The mapping of is given in Table 5.2.2.2.5-3 of TS 38.214 (reproduced below). The amplitude coefficient is represented by

[0092]

[0093] For l=1,…,v.

[0094] Let f l * ∈{0,1,…,M v -1} is i 2,4,l The index of yes The index of the strongest coefficient of layer l, i.e. 2,4,l Elements For l = 1, ..., v. n 3,l The codebook index is relative to is remapped to So that after remapping, Index f relative to f l * is remapped to f = (ff l * )mod M v , so that after remapping, the index of the strongest coefficient is f l * =0(l=1,…,v). i 2,4,l 、i 2,5,l andi 1,7,l The index indicates the amplitude coefficient, phase coefficient and bitmap after remapping.

[0095] The strongest coefficient of layer l is given by i 1,8,l ∈{0,1,…,2L-1} identification, which is obtained as follows:

[0096]

[0097] For l=1,…,v.

[0098] Table 5.2.2.2.5-2:i 2,3,l A mapping of elements: arrive

[0099]

[0100] The amplitude and phase coefficient indicators are reported as follows:

[0101] - and For l = 1, ..., v, no indicator is reported and

[0102] - For l=1,…,v, report indicator

[0103] -Report K NZ -v indicator in

[0104] -Report K NZ -v indicator c l,i,f ,in

[0105] - Unreported remaining 2L·M ν ·vK NZ indicator

[0106] - Unreported remaining 2L·M ν ·vK NZ Indicator c l,i,f .

[0107] Table 5.2.2.2.5-3:i 2,4,l A mapping of elements: arrive

[0108]

[0109]

[0110] Using the algorithm described in Section 5.2.2.2.3 of TS 38.214 from i 1,2 Find the elements of n1 and n2 where the values ​​of C(x,y) are given in Table 5.2.2.2.5-4 of TS 38.214 (reproduced below).

[0111] For N3>19, M initial byi 1,5 Identification.

[0112] For all values ​​of N3, for l=1,…,v, If M v>1, then use C(x,y) as defined in Table 5.2.2.2.5-4 in TS 38.214 and the following algorithm, for N3≤19, from i 1,6,l (l=1,…,v) is found, and for N3>19, from i 1,6,l (l=1,…,v) and M initial Found by Identification 3,l The non-zero elements of are:

[0113] s0=0

[0114] for f=1,…,M v -1

[0115] Find the maximum x in Table 5.2.2.2.5-4 * ∈{M v -1-f,…,N3-1-f}, so that

[0116] i 1,6,l -s f-1 ≥C(x * ,M v -f)

[0117] e f =C(x * ,M v -f)

[0118] s f =s f-1 +e f

[0119] if N3≤19

[0120]

[0121] else

[0122]

[0123] else

[0124]

[0125] end if

[0126] end if

[0127] Table 5.2.2.2.5-4: Combination coefficient C(x,y)

[0128]

[0129] When n 3,l and M initialWhen known, find i as follows 1,5 andi 1,6,l (l=1,…,v):

[0130] -If N3≤19, then i 1,5 = 0 and is not reported. v =1, then i 1,6,l = 0 for l = 1,…,v, and is not reported. v >1, then where C(x,y) is given in Table 5.2.2.2.5-4 and where index f = 1,…,M v -1 is assigned so that as f increases, Increase.

[0131] -If N3>19, then M initial byi 1,5 Instructions, which are reported and given by

[0132]

[0133] Only non-zero indices are reported Where IntS={(M initial +i)modN3,i=0,1,…,2M v -1}, where index f = 1,…,M v -1 is assigned so that as f increases, Increase.

[0134]

[0135] but where C(x,y) is given in Table 5.2.2.2.5-4.

[0136] The codebooks for layers 1 to 4 are given in Table 5.2.2.2.5-5 of TS 38.214, where For i=0,1,…,L-1, Obtained as in Section 5.2.2.2.3 of TS 38.214, and the number and t,l Given by

[0137]

[0138] where t = {0, 1, ..., N3-1}, which is the index associated with the precoding matrix l = {1, ..., v}, and where

[0139]

[0140] For f=0,1,…,M v -1.

[0141] Based on the above, May be determined and reported to the network.

[0142] To incorporate the optimal phase adjustment factor associated with TRP n into the PMI of TRP n, in some embodiments, Can be multiplied by the corresponding phase adjustment factor As shown below:

[0143]

[0144] Phase adjustment factor of data layer l Can be phase-shifted are multiplied together to form a single combining factor, e.g.

[0145]

[0146] In some embodiments, the combining factor is indicated in the PMI feedback message. For example, when 16PSK is applied,

[0147]

[0148] By sending c′ in the PMI feedback message l,i,f To replace c l,i,f , each layer phase adjustment factor Sent back to the network as part of the eType2 PMI.

[0149] It should be noted that the phases of all delay taps (including the strongest one (ie, )). In other words, the phase of the strongest frequency domain component of each data layer is reported to the BS.

[0150] In summary, in Solution 1, the UE may incorporate the phase adjustment factor associated with the data layer of the corresponding TRP and associated with all subbands into the PMI of the corresponding TRP to be reported in the CSI feedback message transmitted to the network.

[0151] Solution 2:

[0152] In solution 2, the UE may determine the phase adjustment factor matrix associated with the corresponding subband t For example, in is the phase adjustment factor for data layer l from TRP n and for subband t, the value of “l” ranges from 1 to R, and R is the rank indicated by RI, which may range from 1 to 4 in some embodiments. The phase adjustment factor matrix may be best applied for each subband t, and the UE may incorporate it into the PMI to be reported to the network. It should be noted that the phase adjustment factor may be in other forms. For example, for each subband t and for each data layer l, the UE may determine a set of phase adjustment factors, where the set includes Or the UE may determine several phase adjustment factors, the first of which is The second is ..., and the Nth one is

[0153] For subband t, the optimal phase adjustment factor can be determined as follows:

[0154]

[0155] in

[0156]

[0157] where a n,t is the amplitude adjustment factor, H ,t is the channel matrix, and W n,t is the precoding matrix for TRP n in subband t.

[0158] The present disclosure proposes to incorporate the subband-dependent phase adjustment factor into the eType 2 PMI. In order to incorporate the optimal phase adjustment factor associated with TRP n into the PMI of TRP n, in some embodiments, Can be multiplied by the corresponding phase adjustment factor As shown below:

[0159]

[0160] item is the sum of the terms indicated by the bitmap in PMI component i1. For ease of notation, let are those items whose natural index is f. For those items not indicated by the bitmap, is taken as 0. Then, Can be transformed as follows:

[0161]

[0162] item Is a sequence The inverse discrete Fourier transform (IDFT) of ).

[0163]

[0164] in

[0165]

[0166] in

[0167]

[0168] in short,

[0169]

[0170] where operator represents the Hadamard (element-wise) product, and the operator Represents a convolution operation.

[0171] Therefore, in some embodiments, Can be replaced Feedback is done as part of the eType 2PMI feedback. That is, instead of and And the encoding and and and exist and In the encoding of The new nonzero entries in .

[0172] It should be noted that the phases of all delay taps may be reported to the network, including the strongest one (ie, ). In other words, the phase of the strongest frequency domain component of each data layer is reported to the BS.

[0173] In summary, in Solution 2, the UE may incorporate the phase adjustment factor associated with the data layer of the corresponding TRP and associated with the corresponding subband into the PMI of the corresponding TRP to be reported in the CSI feedback message transmitted to the network.

[0174] Solution 3:

[0175] In solution 3, the UE may include the phase adjustment factor as an additional part of the PMI as part of the CSI feedback message and transmit the CSI feedback message to the network. In some embodiments, each phase adjustment factor (e.g. ) is associated with the data layer of the corresponding TRP and is associated with all subbands. In some other embodiments, each phase adjustment factor (e.g. ) is associated with the data layer of the corresponding TRP and is associated with the corresponding subband.

[0176] For example, each phase adjustment factor It can be quantized, for example, using 16PSK as follows:

[0177]

[0178] Solution 3 is simple and does not change the eType 2 codebook, for example, by calculating Or index (i1,i2).

[0179] According to some embodiments of the present disclosure, each PMI included in the CSI feedback message may additionally or alternatively include an amplitude adjustment factor (e.g., a) of a codeword associated with a corresponding CSI-RS resource or a corresponding TRP (e.g., TRP n). n ). The amplitude adjustment factor may be determined based on the UE implementation.

[0180] Figure 2 An exemplary method for transmitting CSI feedback information performed by a UE according to some embodiments of the present disclosure is described. It is considered that the method may also be performed by other devices having similar functions.

[0181] In operation 201, the UE may receive a CSI report configuration message indicating a plurality of CSI-RS resources for channel measurement and at least one zero power or non-zero power CSI-RS resource for interference measurement, wherein each of the plurality of CSI-RS resources is associated with a CRI and the same number of CSI-RS ports. In operation 202, the UE may perform a channel measurement procedure based on the CSI report configuration message. In operation 203, the UE may select a CSI-RS resource set from the plurality of CSI-RS resources for joint transmission based on the channel measurement procedure. In operation 204, the UE may transmit a CSI feedback message after performing the channel measurement procedure, wherein the CSI feedback message includes a single RI, a single CQI, and a PMI set, wherein each PMI in the PMI set is associated with a corresponding CSI-RS resource in the selected CSI-RS resource set, and wherein the RI indicates a rank applied to each CSI-RS resource in the selected CSI-RS resource set, and the CQI indicates a channel quality associated with all CSI-RS resources in the selected CSI-RS resource set.

[0182] According to some embodiments, each PMI in the PMI set is based on the eType 2 codebook and may incorporate or include a number of phase adjustment factors, where the total number of phase adjustment factors is equal to the value of the RI, and each phase adjustment factor is associated with a data layer of a corresponding CSI-RS resource. For example, the phase adjustment factor may be incorporated or included in the PMI in a manner as described in any of the solutions 1 to 3 above. In an embodiment, each phase adjustment factor is associated with all subbands. In another embodiment, each phase adjustment factor is associated with a corresponding subband. Additionally or alternatively, each PMI in the PMI set may include an amplitude adjustment factor for a codeword associated with a corresponding CSI-RS resource.

[0183] Figure 3 An exemplary method performed by a BS according to some embodiments of the present disclosure is described. It is considered that the method may also be performed by other devices having similar functions.

[0184] In operation 301, the BS may transmit a CSI report configuration message indicating a plurality of CSI-RS resources for channel measurement and at least one zero power or non-zero power CSI-RS resource for interference measurement, wherein each of the plurality of CSI-RS resources is associated with a CRI and the same number of CSI-RS ports. In operation 302, the BS may receive a CSI feedback message including a single RI, a single CQI, and a PMI set, wherein each PMI in the PMI set is associated with a corresponding CSI-RS resource in a subset of the plurality of CSI-RS resources, and wherein the RI indicates a rank applied to each CSI-RS resource in the subset of the plurality of CSI-RS resources, and the CQI indicates channel quality associated with all CSI-RS resources in the subset of the plurality of CSI-RS resources.

[0185] According to some embodiments, each PMI in the PMI set is based on the eType 2 codebook and may incorporate or include a number of phase adjustment factors, where the total number of phase adjustment factors is equal to the value of the RI, and each phase adjustment factor is associated with a data layer of a corresponding CSI-RS resource. For example, the phase adjustment factor may be incorporated or included in the PMI in a manner as described in any of the solutions 1 to 3 above. In an embodiment, each phase adjustment factor is associated with all subbands. In another embodiment, each phase adjustment factor is associated with a corresponding subband. Additionally or alternatively, each PMI in the PMI set may include an amplitude adjustment factor for a codeword associated with a corresponding CSI-RS resource.

[0186] Figure 4 A simplified block diagram illustrating an exemplary apparatus 400 in accordance with some embodiments of the present disclosure.

[0187] like Figure 4, an example of an apparatus 400 may include at least one processor 404 and at least one transceiver 402 coupled to the processor 404. The apparatus 400 may be a UE, a BS, or any other device having similar functionality.

[0188] Although elements such as transceiver 402 and processor 404 are described in singular form in this figure, the plural form is contemplated unless explicitly limited to the singular form. In some embodiments of the present disclosure, transceiver 402 may be divided into two devices, such as receive circuitry and transmit circuitry. In some embodiments of the present disclosure, apparatus 400 may further include an input device, a memory, and / or other components.

[0189] In some embodiments of the present disclosure, the device 400 may be a UE. The transceiver 402 and the processor 404 may interact with each other to perform the following steps: Figures 1 to 3 . For example, the transceiver 402 may be configured to receive a CSI report configuration message indicating a plurality of CSI-RS resources for channel measurement and at least one zero power or non-zero power CSI-RS resource for interference measurement, wherein each of the plurality of CSI-RS resources is associated with a CRI and the same number of CSI-RS ports; the processor 404 may be configured to perform a channel measurement procedure based on the CSI report configuration message, and select a CSI-RS resource set from the plurality of CSI-RS resources for joint transmission based on the channel measurement procedure; and the transceiver 402 may be further configured to: transmit a CSI feedback message after performing the channel measurement procedure, wherein the CSI feedback message includes a single RI, a single CQI, and a PMI set, wherein each PMI in the PMI set is associated with a corresponding CSI-RS resource in the selected CSI-RS resource set, and wherein the RI indicates a rank applied to each CSI-RS resource in the selected CSI-RS resource set, and the CQI indicates a channel quality associated with all CSI-RS resources in the selected CSI-RS resource set.

[0190] In some embodiments of the present disclosure, the device 400 may be a BS. The transceiver 402 and the processor 404 may interact with each other to perform the following steps: Figures 1 to 3For example, the transceiver 402 may be configured to transmit a CSI report configuration message indicating a plurality of CSI-RS resources for channel measurement and at least one zero power or non-zero power CSI-RS resource for interference measurement, wherein each CSI-RS resource in the plurality of CSI-RS resources is associated with a CRI and the same number of CSI-RS ports; and the transceiver 402 may be further configured to receive a CSI feedback message including a single RI, a single CQI, and a PMI set, wherein each PMI in the PMI set is associated with a corresponding CSI-RS resource in a subset of the plurality of CSI-RS resources, and wherein the RI indicates a rank applied to each CSI-RS resource in the subset of the plurality of CSI-RS resources, and the CQI indicates a channel quality associated with all CSI-RS resources in the subset of the plurality of CSI-RS resources.

[0191] In some embodiments of the present disclosure, the apparatus 400 may further include at least one non-transitory computer-readable medium.

[0192] For example, in some embodiments of the present disclosure, a non-transitory computer-readable medium may have computer-executable instructions stored thereon to cause the processor 404 to implement the method performed by the UE as described above. For example, when the computer-executable instructions are executed, the processor 404 interacts with the transceiver 402 to perform the method described above. Figures 1 to 3 Operation of the UE described in any one of the foregoing.

[0193] In some embodiments of the present disclosure, a non-transitory computer-readable medium may have computer-executable instructions stored thereon to cause the processor 404 to implement the method performed by the BS as described above. For example, when the computer-executable instructions are executed, the processor 404 interacts with the transceiver 402 to perform the method described above. Figures 1 to 3 The operation of the BS described by any one of .

[0194] The method of the present disclosure can be implemented on a programmed processor. However, the controller, flow chart and module can also be implemented on a general or special purpose computer, a programmed microprocessor or microcontroller and peripheral integrated circuit components, an integrated circuit, a hardware electronic or logic circuit (such as a discrete element circuit), a programmable logic device, etc. In general, any device with a finite state machine capable of implementing the flow chart shown in the figure can be used to implement the processing functions of the present disclosure.

[0195] Although the present disclosure has been described with its specific embodiments, it is apparent that many alternatives, modifications and variations will be apparent to those skilled in the art. For example, the various components of the embodiments may be interchanged, added or replaced in other embodiments. In addition, all elements shown in each figure are not necessary for the operation of the disclosed embodiments. For example, a person skilled in the art of the disclosed embodiments will be able to make and use the teachings of the present disclosure by simply adopting the elements of the independent claims. Therefore, the embodiments of the present disclosure set forth herein are intended to be illustrative rather than restrictive. Various changes may be made without departing from the spirit and scope of the present disclosure.

[0196] In the present disclosure, for example, relational terms such as "first", "second" etc. can be used only to distinguish an entity or action from another entity or action, and do not necessarily require or imply any actual this relationship or order between such entities or actions. The term "comprises / comprising" or any other variation thereof is intended to cover non-exclusive inclusion, so that the process, method, article or equipment including the element list not only includes those elements but also may include other elements that are not clearly listed or inherent to this process, method, article or equipment. The elements starting with "a / an" etc. do not exclude the presence of additional identical elements in the process, method, article or equipment including the element without more constraints. In addition, the term "another" is defined as at least the second or more. As used herein, the terms "include", "have" etc. are defined as "include".

Claims

1. A user equipment UE, comprising: A transceiver configured to: receiving a channel state information (CSI) reporting configuration message indicating a plurality of channel state information reference signal (CSI-RS) resources for channel measurement and at least one zero power or non-zero power CSI-RS resource for interference measurement, wherein each CSI-RS resource of the plurality of CSI-RS resources is associated with a CSI-RS resource indicator (CRI) and the same number of CSI-RS ports; and a processor coupled to the transceiver and configured to: Perform a channel measurement procedure based on the CSI report configuration message; and selecting a CSI-RS resource set from the plurality of CSI-RS resources for joint transmission based on the channel measurement procedure; wherein the transceiver is further configured to: A CSI feedback message is transmitted after performing the channel measurement procedure, wherein the CSI feedback message includes a single rank indicator RI, a single channel quality indicator CQI, and a precoding matrix indicator PMI set, wherein each PMI in the PMI set is associated with a corresponding CSI-RS resource in the selected CSI-RS resource set, and wherein the RI indicates a rank applied to each CSI-RS resource in the selected CSI-RS resource set, and the CQI indicates a channel quality associated with all CSI-RS resources in the selected CSI-RS resource set.

2. The UE according to claim 1, wherein each PMI in the PMI set is based on an eType 2 codebook and includes a phase of a strongest frequency domain component of each data layer.

3. The UE of claim 2, wherein each PMI in the PMI set incorporates a number of phase adjustment factors, the total number of the phase adjustment factors is equal to the value of the RI, and each phase adjustment factor is associated with a data layer of the corresponding CSI-RS resource. The UE of claim 3 , wherein each phase adjustment factor is associated with all subbands. The UE of claim 3 , wherein each phase adjustment factor is associated with a corresponding subband.

6. The UE according to claim 1, wherein each PMI in the PMI set is based on an eType 2 codebook and includes a plurality of phase adjustment factors, the total number of the phase adjustment factors is equal to the value of the RI, and each phase adjustment factor is associated with a data layer of the corresponding CSI-RS resource. The UE of claim 6 , wherein each phase adjustment factor is associated with a corresponding subband.

8. The UE of claim 6, wherein each phase adjustment factor is associated with all subbands.

9. The UE of claim 1, wherein each PMI in the PMI set comprises an amplitude adjustment factor for a codeword associated with the corresponding CSI-RS resource.

10. A base station BS, comprising: A transceiver configured to: transmitting a channel state information (CSI) reporting configuration message indicating a plurality of channel state information reference signal (CSI-RS) resources for channel measurement and at least one zero power or non-zero power CSI-RS resource for interference measurement, wherein each CSI-RS resource of the plurality of CSI-RS resources is associated with a CSI-RS resource indicator (CRI) and the same number of CSI-RS ports; and receiving a CSI feedback message including a single rank indicator (RI), a single channel quality indicator (CQI), and a precoding matrix indicator (PMI) set, wherein each PMI in the PMI set is associated with a corresponding CSI-RS resource in a subset of the plurality of CSI-RS resources, and wherein the RI indicates a rank applied to each CSI-RS resource in the subset of the plurality of CSI-RS resources, and the CQI indicates a channel quality associated with all CSI-RS resources in the subset of the plurality of CSI-RS resources; and A processor is coupled to the transceiver. 11 . The BS of claim 10 , wherein each PMI in the PMI set is based on an eType 2 codebook and includes a phase of a strongest frequency domain component of each data layer.

12. The BS of claim 11, wherein each PMI in the PMI set incorporates a number of phase adjustment factors, a total number of the phase adjustment factors is equal to the value of the RI, and each phase adjustment factor is associated with a data layer of the corresponding CSI-RS resource.

13. The BS of claim 10, wherein each PMI in the PMI set is based on an eType 2 codebook and includes a plurality of phase adjustment factors, a total number of the phase adjustment factors is equal to a value of the RI, and each phase adjustment factor is associated with a data layer of the corresponding CSI-RS resource.

14. The BS of claim 10, wherein each PMI in the PMI set comprises an amplitude adjustment factor for a codeword associated with the corresponding CSI-RS resource.

15. A method performed by a user equipment UE, comprising: receiving a channel state information (CSI) reporting configuration message indicating a plurality of channel state information reference signal (CSI-RS) resources for channel measurement and at least one zero power or non-zero power CSI-RS resource for interference measurement, wherein each CSI-RS resource of the plurality of CSI-RS resources is associated with a CSI-RS resource indicator (CRI) and the same number of CSI-RS ports; Execute a channel measurement procedure based on the CSI report configuration message; selecting a CSI-RS resource set from the plurality of CSI-RS resources for joint transmission based on the channel measurement procedure; and A CSI feedback message is transmitted after performing the channel measurement procedure, wherein the CSI feedback message includes a single rank indicator RI, a single channel quality indicator CQI, and a precoding matrix indicator PMI set, wherein each PMI in the PMI set is associated with a corresponding CSI-RS resource in the selected CSI-RS resource set, and wherein the RI indicates a rank applied to each CSI-RS resource in the selected CSI-RS resource set, and the CQI indicates a channel quality associated with all CSI-RS resources in the selected CSI-RS resource set.

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