dback HARQ feedback channel allocation to acknowledge the successful Allocation detection of this information element. SizeOffset Offset used to compute burst size index. MIMO Encoder MIMO encoder format for uplink feedback transmission Format (non-adaptive precoding is used at the MS): Obo SFBC; 0b1 Vertical encoding with two streams or one stream, if the MS has only one transmit antenna. Long TTI Indicator Indicates number of subframes spanned by the allocated resource: Obo 1 subframe (default); 0b1 4 UL subframes for FDD or all UL subframes for TDD. HARQ channel identifier. MFM Allocation Index Ob00 MFM 0 with Measurement Method Indication = 0; 0b01 MFM 3 with all subbands; 0b10 MFM 6 with all subbands; Ob11 MFM is defined in Feedback Polling A-MAP IE with Polling Sub-type = Ob1. Maximum Number of 1 or 2 depending on the MIMO feedback mode. Transmit Streams Short-term and Long- The resources are allocated in frames with short or long period. The term Periods short feedback period is p frames. The long feedback period is q superframes. The first allocation starts two frames later. The frame index is given by i+2, where i is the index of the frame where the Feedback Polling A-MAP IE is transmitted. (Continued) CHAPTER 10 The IEEE 802. 16m Physical Layer (Part II) Table 10-13 Feedback Polling A-MAP IE Parameters [2] Continued Parameter (Bits) Description The transmission of MIMO feedback modes in MFM Allocation Index is allocated with a short period, whereas the transmit correlation matrix is scheduled with a long period. Short and long period reports start at the first allocation. When short and long period feedback reports coincide in the same frame, both short period feedback content and long period feedback content are sent in the same burst. ACK Allocation Flag MIMO Feedback IE Obo feedback allocation for single-BS MIMO operation; 0b1 feedback allocation for multi-BS MIMO operation. Measurement Obo Use the midamble for CQI measurements; Method Indication Ob1 Use pilots in open-loop region with Ns streams for