number of preamble symbols received. Where one of these optional values is used the PHR encoding shall be the nearest smaller length value. Table 9 nominal data rates – Data rate R1–R0 Mb/s 00 0.11 01 0.85 10 6.81 11 27.24 PHR SECDED check bits The SECDED (single correct, double error detect) field, C5–C0, is a set of six parity check bits that are used to protect the PHR from errors caused by noise and channel impairments. The SECDED bits are a simple Hamming block code that enables the correction of a single error and the detection of two errors at the receiver. The SECDED bit values depend on PHR bits 0–12 and are computed as follows: C0 = (R0, R1, L0, L2, L4, L5, EXT, P1) XOR C1 = (R1, L2, L3, L5, L6, RNG, EXT, P0) XOR C2 = (R0, L0, L1, L5, L6, RNG, EXT) XOR C3 = (L0, L1, L2, L3, L4, RNG, EXT) XOR C4 = (P0, P1) XOR C5 = (R1, R0, L6, L5, L4, L3, L2, L1, L0, RNG, EXT, P1, P0, C4, C3, C2, C1, C0) XOR Data field The Data is the last component of the PPDU and is encoded as shown in Figure 7. Figure 7 data field encoding process – The data field shall be formed as follows: Encode the PSDU using systematic Reed-Solomon block code, which adds 48 parity bits as described in 2.3.3.1.
number of preamble symbols received. Where one of these optional values is used the PHR encoding shall be the nearest smaller length value. Table 9 – nominal data rates R1–R0 Data rate Mb/s 00 0.11 01 0.85 10 6.81 11 27.24 PHR SECDED check bits The SECDED (single correct, double error detect) field, C5–C0, is a set of six parity check bits that are used to protect the PHR from errors caused by noise and channel impairments. The SECDED bits are a simple Hamming block code that enables the correction of a single error and the detection of two errors at the receiver. The SECDED bit values depend on PHR bits 0–12 and are computed as follows: C0 = XOR (R0, R1, L0, L2, L4, L5, EXT, P1) C1 = XOR (R1, L2, L3, L5, L6, RNG, EXT, P0) C2 = XOR (R0, L0, L1, L5, L6, RNG, EXT) C3 = XOR (L0, L1, L2, L3, L4, RNG, EXT) C4 = XOR (P0, P1) C5 = XOR (R1, R0, L6, L5, L4, L3, L2, L1, L0, RNG, EXT, P1, P0, C4, C3, C2, C1, C0) Data field The Data is the last component of the PPDU and is encoded as shown in Figure 7. Figure 7 – data field encoding process The data field shall be formed as follows: Encode the PSDU using systematic Reed-Solomon block code, which adds 48 parity bits as described in 2.3.3.1.