— Short guard interval (transmit and receive) A TVHT STA may optionally support: — TVHT_MODE_2C, TVHT_MODE_2N, TVHT_MODE_4C, or TVHT_MODE_4N (Two or four frequency segments) — Two or more spatial streams (transmit and receive) — Beamforming sounding (by sending a VHT NDP frame) — Respond to transmit beamforming sounding (provide compressed beamforming feedback) — STBC (transmit and receive) — LDPC (transmit and receive) — MU (transmit and receive) — MCSs 8 and 9 (transmit and receive) The tone spacing, DFT duration and the other timing parameters remain unchanged for all optional modes compared with the mandatory mode (one segment). The DATA encoding process for transmissions is similar to one segment transmission. TVHT supports following formats Non-HT format (NON_HT). (NON_HT_DUP_OFDM only) TVHT format (TVHT). Support for TVHT format is mandatory. TVHT supports 1 to 4 single user space-time streams and up to four user multi user transmission. The following table summarises timing related parameters and tone location. Parameter 6 MHz 7 MHz 8 MHz Description NSD 108 108 108 Number of complex data numbers per frequency segment NSP 6 6 6 Number of pilot values per frequency segment NST 114 114 114 Total number of subcarriers per frequency segment NSR 58 58 58 Highest data subcarrier index per frequency segment ∆F Subcarrier frequency spacing TDFT 24 µs 24 µs 18 µs IDFT/DFT period
TGI 6 µs = TDFT /4 6 µs = TDFT /4 4.5 µs = TDFT /4 Guard interval duration Parameter Description NST 114 114 114 114 114 Total number of occupied subcarriers per frequency segment NTT 114 228 228 456 456 Total number of occupied subcarriers across all frequency segments -58 to -2 and +2 to +58 -130 to -74, to -14, +14 to +70, and +74 to +130 -58 to -2 and +2 to +58 for each frequency segment -274 to -218, to -158, -130 to -74, -70 to -14, +14 to +70, +74 to +130, +158 to 214, and +218 to +274 -130 to -74, -70 to -14, +14 to +70, and +74 to +130 for each frequency segment Location of occupied subcarriers for 6 MHz and 8 MHz channel -58 to -2 and +2 to +58 -142 to -86, to -26, +26 to +82, and +86 to +142 -58 to -2 and +2 to +58 for each frequency segment -310 to -254, to -194, -142 to -86, -82 to -26, +26 to +82, +86 to +142, +194 to 250, and +254 to +310 -142 to -86, -82 to -26, +26 to +82, and +86 to +142 for each frequency segment Location of occupied subcarriers for 7 MHz Other adjustments according to bandwidth, timing, etc. Cyclic shift value PMD receiver specification aPPDUMaxTime MCS datarate Etc… Propose: TGaf Editor: Make changes as shown and correct all cross-references in the draft. TGaf Editor: Insert a new Clause 23 following Clause 22 as follows: N 70
Data field General (See 22.3.10.1 (General) with TVHT replacing VHT). SERVICE field (See 22.3.10.2 (SERVICE with TVHT replacing VHT). 23.3.10.3 CRC calculation for TVHT-SIG-B The CRC calculation and insertion is illustrated in Figure 22-21 (VHT-SIG-B and SERVICE field relationship). The value of the CRC field shall be the ones complement of Equation (22-55) with the values of set to 21 for all Modes. Scrambler (see 22.3.10.4 (Scrambler)) 23.3.10.5 Coding (see 22.3.10.5 (Coding) with TVHT replacing VHT) 23.3.10.6 Stream parser After coding and puncturing, the data bit streams at the output of the FEC encoders are processed in groups of NCBPS bits. Each of these groups is(#5185) re-arranged into NSS blocks of NCBPSS bits (NSS,u blocks of NCBPSS,u bits in the case of an MU(#4668) transmission). This operation is referred to as “stream parsing” and is described in 22.3.10.6 (Stream parser). Segment parser The segment parser is not used in Clause 23. All modes of operation use an interleaver. BCC interleaver The BCC interleaver and deinterleaver for one frequency segment (TVHT_MODE_1) is as defined in 22.3.10.8 (BCC interleaver) for 40 MHz. The BCC interleaver and deinterleaver for TVHT_MODE_2C, TVHT_MODE_2N, TVHT_MODE_4C and TVHT_MODE_4N re-use the same formulas as described in 22.3.10.8 (BCC interleaver) for 40 MHz with values for , NROW and NROT as defined in Table 23-17. Table 23-17- Number of rows and columns in the interleaver Parameter TVHT_MODE_1 TVHT_MODE_2C, TVHT_MODE_2N TVHT_MODE_4C, TVHT_MODE_4N 18 27 48 8 x NBPSCS 9 x NBPSCS