he corresponding CQI. MIMO feedback mode 6 is used for closed-loop MU-MIMO in localized permutation zones to assist frequency selective scheduling. In this mode, the MS feedback includes the sub-band selection, corresponding CQI, and sub-band PMI. The sub-band CQI refers to the CQI of the best PMI in the sub- band. A rank-1 codebook or its subset is used to estimate the PMI in a sub-band. MIMO feedback mode 7 is used for closed-loop MU-MIMO in distributed permutation zones using wideband beam- forming. In this mode, the MS is required to feedback the wideband CQI. The wideband CQI estimated at the MS assuming short-term or long-term precoding at the BS according to the feedback period. The channel state information may be obtained at the BS, the correlation matrix, or the wideband PMI that is sent by the MS. The downlink MIMO parameters are summarized in Table 10-26. The serving BS provides common configuration parameters for downlink MIMO operation using broadcast messages. The broadcast information is carried through the S-SFH SP3 IE or in additional broadcast information such as the AAI_SCD or AAI_DL-IM MAC management messages. Individual downlink MIMO configuration parameters are transmitted through unicast messages. The unicast information is carried in the DL Basic Assignment A-MAP IE, DL Sub-band Assignment A-MAP IE, DL Persistent A-MAP IE, Feedback Polling A-MAP IE, and Feedback Allocation A-MAP IE. There are three types of codebook feedback modes as follows: (1) base mode, where the feedback from an MS indicates an entry of the base codebook that is used by the BS to determine a new precoder; (2) transformation mode, where the PMI feedback from an MS represents an entry in the transformed base codebook according to long-term channel information; and (3) differential mode where the PMI feedback from an MS refers to an entry in the differential codebook or an entry in the base codebook on PMI reset. In the latter case, the feedback from an MS provides differential knowledge of the short-term channel inform