n-adaptive multiplexing) Mode 2 Closed-loop SU-MIMO (spatial Vertical encoding Adaptive multiplexing) Mode 3 Open-loop collaborative spatial Vertical encoding Non-adaptive multiplexing (MU-MIMO) Mode 4 Closed-loop collaborative spatial Vertical encoding Adaptive multiplexing (MU-MIMO) Table 10-30 Uplink MIMO Parameters [2] Number of Transmit Spatial Rate Number of Number of Number of Antennas (Nt) per Layer (R) Streams (Ns) Sub-carriers Layers (L) MIMO Mode 0 MIMO Mode 1 and MIMO Mode 2 MIMO Mode 3 and MIMO Mode 4 It must be noted that Ns denotes the number of streams that are transmitted by a single MS. In MIMO modes 3 and 4, N refers to the number of transmit antennas at each participating mobile station in collaborative spatial multiplexing. All MIMO modes are supported in either distributed or localized subchannelization schemes. Table 10-31 shows the permutations supported by each MIMO mode. The successive symbols at the output of the precoder block are mapped to the corresponding antenna ports. The sub-carrier mapping within a logical resource unit starts from the data sub-carrier with the lowest OFDM symbol index and lowest sub-carrier index, and continues with increasing sub-carrier index. If the edge of the resource unit is reached, the mapping is continued on the next OFDM symbol. The serving BS provides the necessary parameters for uplink MIMO operation in a unicast message. The parameters may be transmitted depending on the type of operation, and are carried in the UL Basic Assignment A-MAP IE, UL Sub-band Assignment A-MAP IE, or UL Persistent Allocation A-MAP IE. The base codebook is a unitary codebook. A codebook is defined as unitary, if each of the con- stituent matrices is unitary. The notation C(N, Ns, NB) denotes the codebook that consists of 2NB CHAPTER 10 The IEEE 802. 16m Physical Layer (Part II) Table 10-31 Supported Subchannelization Schemes by Each Uplink MIMO Mode [2] Mini-band CRU Sub- Mini-band CRU band CRU (Localized Tile-based DRU (Diversity Allocation) Allocation) MIMO mode 0 MIMO m