more details on the physical structure and operation of the uplink control channels are provided. 10.3.1 Fast-Feedback Channels The uplink fast-feedback channel carries channel quality indicators and MIMO feedback. There are two types of fast-feedback uplink control channels: Primary Fast-Feedback Channel (PFBCH); and Secondary Fast-Feedback Channel (SFBCH). The PFBCH carries 6 bits of information, providing wideband and narrowband channel quality and MIMO feedback. It is used to support robust feedback reports. The SFBCH carries narrowband CQI and MIMO feedback information. The number of information bits carried in the SFBCH may vary from 7 to 24. A set of predefined numbers of bits in this range is supported. The SFBCH can be used to support CQI reporting at a higher code rate and thus more CQI information bits. The SFBCH can be allocated in a non-periodic manner based on traffic or channel conditions. The number of bits carried in the secondary fast-feedback channel can be adaptive. The fast-feedback channels are frequency-division multiplexed with other uplink control and data channels. The fast-feedback channel starts at a predetermined location with the size defined in a downlink broadcast control message. The fast-feedback channel allocations to an MS can be periodic and the allocations are configurable. For periodic allocations, the specific type of feedback information carried on each fast-feedback opportunity can be different. The fast-feedback channel carries one or more types of fast-feedback information. The physical layer processing of PFBCH and SFBCH is illustrated in Figure 10-12. For PFBCH transmission, four encoding types are specified. The encoding types correspond to MIMO Feedback Mode (MFM) and feedback format in Feedback Allocation A-MAP IE. The primary fast-feedback channel parameters are shown in Table 10-16. As mentioned earlier, the primary fast-feedback channel carries 6 bits of information whose 64 combinations specify the value of Space Time Coding (STC) Rate, Modulation, and Coding S