precoding. PMI Indicator This field is relevant only when PF indicates The MS uses the adaptive codebook precoding. When PMI precoder of rank Ns of its indication is set, the BS can select the precoder choice if PMI indicator is matrix to be used at the MS. zero; otherwise the indicated PMI of rank Ns will used by the MS for precoding. Precoding Matrix Index This parameter is enabled when PF indicates use 0 to 9 when Nt = 2 (PMI) in the Uplink Base of the adaptive codebook precoding, and PMI 0 to 63 when Nt = 4 Codebook indication is set. complex-valued N X Ns matrices and Ns denotes the number of streams. The notation C(N, N5, N,i) denotes the ith codebook entry of C(N1, Ns, NB). The base codebooks of SU-MIMO with two transmit antennas consist of rank-1 codebook C(2,1,4) and rank-2 codebook C(2,2,3). The rank-2 base code- book C(2,2,3) for two transmit antennas in the uplink is the same as the downlink two transmit antennas rank-2 base codebook. The base codebook for uplink collaborative spatial multiplexing is identical to the base codebook for SU-MIMO. 10.7 Multi-BS MIMO Table 10-33 C(2,1,4) Base Codebook Content [2] C(2,1,4,m) [C1,C2] Binary Index 0.7071 -0.7071 0.7071 -0.5000 -0.5000i 0.7071 -0.7071i 0.7071 0.5000 -0.5000i 0.7071 0.7071 0.7071 0.5000 + 0.5000i 0.7071 0.7071i 0.7071 -0.5000 + 0.5000u 1010-1111 10-15 The uplink base codebook for SU-MIMO with four transmit-antennas consists of rank-1 codebook C(4,1,6), rank-2 codebook C(4,2,6), rank-3 codebook C(4,3,6), and rank-4 codebook C(4,4,6). The rank-1 codebook entry C(4,1,6,m) consists of the first column of C(4,4,6,m), rank-2 codebook entry C(4,2,6,m) consists of the first two columns of C(4,4,6,m), and rank-3 codebook entry C(4,3,6,m) consists of the first three columns of C(4,4,6,m) base codebook. As an example, Table 10-33 provides the content of base codebook C(2,1,4). The uplink open-loop MU-MIMO codebook subset is same as the uplink open-loop SU-MIMO codebook subset. The base codebook for uplink collaborative spatial multiplexing is a 4-bit subs