Codebook and PMI override in downlink MU-MIMO transmission
AssigneeTelefonaktiebolaget LM Ericsson (publ)
InventorsYongquan Qiang, Chaocheng Tu, Shaohua Li
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Abstract
A method of operating a network node includes receiving a first precoding matrix indicator, PMI, from a UE, wherein the first PMI is based on an antenna-grouping codebook, selecting a non-antenna-grouping codebook for downlink multi-user multiple input, multiple output, MU-MIMO transmission, determining a second PMI of the non-antenna-grouping codebook based on the first PMI of the antenna-grouping codebook, and performing MU-MIMO pairing and beamforming toward the UE based on the second PMI of the non-antenna-grouping codebook. Related network nodes are disclosed.
Claims12
A method of operating a network node, comprising:
- receiving a first precoding matrix indicator (PMI) from a UE, wherein the first PMI is based on an antenna-grouping codebook;
- selecting a non-antenna-grouping codebook for downlink multi-user multiple input, multiple output (MU-MIMO) transmission;
- determining a second PMI of the non-antenna-grouping codebook based on the first PMI of the antenna-grouping codebook;
- and
- performing MU-MIMO pairing and beamforming toward the UE based on the second PMI of the non-antenna-grouping codebook,
- wherein the first PMI comprises a first set of beam indices of the antenna-grouping codebook associated with the first PMI, wherein the second PMI comprises a second set of beam indices of non-antenna-grouping codebook associated with the second PMI;
- wherein determining the second PMI of non-antenna-grouping codebook comprises selecting the second set of beam indices for which a distance between a precoding matrix associated with the first set of beam indices of antenna-grouping codebook and a precoding matrix associated with the second set of beam indices of non-antenna-grouping codebook is minimized;
- and
- wherein determining the second set of beam indices is performed according to the following equation:
- [
- l
- ,
- l
- ′
- ,
- m
- ,
- m
- ′
- ,
- n
- ]
- =
- arg
-
- (
- min
- l
- ,
- l
- ′
- ,
- m
- ,
- m
- ′
- ,
- n
- d
-
- (
- W
- l
- ,
- m
- ,
- p
- ,
- n
- group
- ,
- W
- l
- ,
- l
- ′
- ,
- m
- ,
- m
- ′
- ,
- n
- non
- -
- group
- )
- )
- where (l,m,p,n) corresponds to the first set of beam indices, and (l,l′,m,m′,n] corresponds to the second set of beam indices,
- W
- l
- ,
- m
- ,
- p
- ,
- n
- group
- corresponds to the precoding matrix associated with the first set of beam indices of antenna-grouping codebook, and
- W
- l
- ,
- l
- ′
- ,
- m
- ,
- m
- ′
- ,
- n
- non
-
- ‐
-
- group
- corresponds to the precoding matrix associated with the second set of beam indices of non-antenna-grouping codebook.
A method of operating a network node, comprising:
- receiving a first precoding matrix indicator (PMI) from a UE, wherein the first PMI is based on an antenna-grouping codebook, wherein the first PMI comprises a first set of beam indices of the antenna-grouping codebook associated with the first PMI;
- selecting a non-antenna-grouping codebook for downlink multi-user multiple input, multiple output (MU-MIMO) transmission;
- determining a second PMI of the non-antenna-grouping codebook based on the first PMI of the antenna-grouping codebook, wherein the second PMI comprises a second set of beam indices of non-antenna-grouping codebook associated with the second PMI;
- performing MU-MIMO pairing and beamforming toward the UE based on the second PMI of the non-antenna-grouping codebook;
- and
- determining the second set of beam indices based on the second PMI,
- wherein the first PMI comprises a set of indicators of (i1,1, i1,2, i1,3, i2), the second PMI comprises a set of indicators of (ĩ1,1, ĩ1,2, ĩ1,3, ĩ2), wherein the second set of beam indices is determined based on the following equations:
- l=ĩ1,1
- m=ĩ1,2
- l′=mod(ĩ1,1+k1,N1O1)
- m′=mod(ĩ1,2+k2,N2O2)
- n=ĩ2
- wherein [l,l′,m,m′,n] corresponds to the second set of beam indices,
- wherein N1, N2 are configured channel state information-reference signal, CSI-RS, ports in horizontal and vertical directions, with corresponding over-sample rates of O1, O2, and
- wherein k1 and k2 are determined from a i1,3 to a k1 and k2 mapping table.
Dependencies are inferred from the claim text.