Method and apparatus for generating a PHY data unit
In a method for generating a physical layer (PHY) data unit for transmission via a communication channel, information bits to be included in the PHY data unit are encoded using a forward error correction (FEC) encoder. Also, the information bits are encoded according to a block coding scheme, where m copies of each bit are included in the information bits, and one or more bits in the m copies of each bit are flipped. The information bits are mapped to a plurality of constellation symbols, and a plurality of orthogonal frequency division multiplexing (OFDM) symbols are generated to include the plurality of constellation symbols. The PHY data unit is generated to include the plurality of OFDM symbols.
1. A method, comprising:
generating, with a processing device, a first preamble for a first data unit that is to be transmitted via a communication channel, wherein the first preamble includes a first signal field, wherein the first signal field provides information for interpreting the first data unit, and wherein the first signal field is modulated according to a first modulation technique;
generating, with the processing device, the first data unit according to a first data unit format, wherein the first data unit includes the first preamble;
generating, with the processing device, a second preamble for a second data unit that is to be transmitted via the communication channel, wherein
the second preamble includes a second signal field,
the second signal field provides information for interpreting the second data unit, and
generating the second preamble includes modulating the second signal field according to a second modulation technique different than the first modulation technique to signal to a receiver that the second data unit is formatted according to a second data unit format different than the first data unit format;
generating a data portion of the second data unit, including
encoding a plurality of bits using a binary convolutional code (BCC) encoder to generate a plurality of BCC coded bits, wherein the BCC encoder continuously encodes incoming bits,
partitioning the plurality of BCC coded bits into a plurality of blocks of BCC coded bits,
encoding the plurality of blocks of BCC coded bits according to a block coding scheme to generate a plurality of block coded bits,
mapping the plurality of block coded bits to a plurality of constellation symbols, and
generating a plurality of orthogonal frequency division multiplexing (OFDM) symbols based on the plurality of constellation symbols; and
generating, with the processing device, the second data unit according to the second data unit format, wherein the second data unit includes the second preamble and the data portion;
wherein generating the first data unit according to the first data unit format does not include using the block coding scheme.
2. The method of claim 1 , wherein
the first preamble is generated to include a first long training field (LTF),
the second preamble is generated to include a second LTF, and
the second LTF has a duration longer than a duration of the first LTF.
3. The method of claim 1 , wherein
the first preamble is generated to include a first short training field (STF) to facilitate detection of the first data unit,
the second preamble is generated to include a second STF to facilitate detection of the second data unit, and
the second STF has a duration longer than a duration of the first STF.
4. The method of claim 1 , wherein
the first modulation technique includes using quaternary binary phase shift keying (QBPSK), and
the second modulation technique includes using binary phase shift keying (BPSK) and not using QBPSK.
5. The method of claim 1 , wherein encoding the plurality of blocks of BCC coded bits according to the block coding scheme comprises generating a number of copies of each bit of the plurality of BCC coded bits.
6. The method of claim 5 , wherein encoding the plurality of blocks of BCC coded bits according to the block coding scheme comprises repeating each block of the plurality of blocks of BCC coded bits m times, wherein m is an integer greater than 1, so that m copies of each block of the plurality of blocks of BCC coded bits are included in the plurality of block coded bits.
7. The method of claim 6 , wherein encoding the plurality of blocks of BCC coded bits according to the block coding scheme comprises, in each set of m consecutive copies of each block of the plurality of blocks of BCC coded bits, exclusive-ORing at least one of the m copies with a sequence of bits.
8. An apparatus, comprising:
a network interface having one or more integrated IC s configured to:
generate a first preamble for a first data unit that is to be transmitted via a communication channel, wherein the first preamble includes a first signal field, wherein the first signal field provides information for interpreting the first data unit, and wherein the first signal field is modulated according to a first modulation technique;
generate the first data unit according to a first data unit format, wherein the first data unit includes the first preamble;
generate a second preamble for a second data unit that is to be transmitted via the communication channel, wherein
the second preamble includes a second signal field,
the second signal field provides information for interpreting the second data unit, and
generating the second preamble includes modulating the second signal field according to a second modulation technique different than the first modulation technique to signal to a receiver that the second data unit is formatted according to a second data unit format different than the first data unit format;
generate a data portion of the second data unit, including:
encoding a plurality of bits using a binary convolutional code (BCC) encoder to generate a plurality of BCC coded bits, wherein the BCC encoder continuously encodes incoming bits,
partitioning the plurality of BCC coded bits into a plurality of blocks of BCC coded bits,
encoding the plurality of blocks of BCC coded bits according to a block coding scheme to generate a plurality of block coded bits,
mapping the plurality of block coded bits to a plurality of constellation symbols, and
generating a plurality of orthogonal frequency division multiplexing (OFDM) symbols based on the plurality of constellation symbols; and
generate the second data unit according to a second data unit format, wherein the second data unit includes the second preamble and the data portion;
wherein generating the first data unit according to the first format does not include using the block coding scheme.
9. The apparatus of claim 8 , wherein
the first preamble is generated to include a first long training field (LTF),
the second preamble is generated to include a second LTF, and
the second LTF has a duration longer than a duration of the first LTF.
10. The apparatus of claim 8 , wherein
the first preamble is generated to include a first short training field (STF) to facilitate detection of the first data unit,
the second preamble is generated to include a second STF to facilitate detection of the second data unit, and
the second STF has a duration longer than a duration of the first STF.
11. The apparatus of claim 8 , wherein
the first modulation technique includes using quaternary binary phase shift keying (QBPSK), and
the second modulation technique includes using binary phase shift keying (BPSK) and not using QBPSK.
12. The apparatus of claim 8 , wherein encoding the plurality of blocks of BCC coded bits according to the block coding scheme comprises generating a number of copies of each bit of the plurality of BCC coded bits.
13. The apparatus of claim 12 , wherein encoding the plurality of blocks of BCC coded bits according to the block coding scheme comprises repeating each block of the plurality of blocks of BCC coded bits m times, wherein m is an integer greater than 1, so that m copies of each block of the plurality of blocks of BCC coded bits are included in the plurality of block coded bits.
14. The apparatus of claim 13 , wherein encoding the plurality of blocks of BCC coded bits according to the block coding scheme comprises, in each set of m consecutive copies of each block of the plurality of blocks of BCC coded bits, exclusive-ORing at least one of the m copies with a sequence of bits.
15. The apparatus of claim 8 , further comprising:
one or more antennas coupled to the network interface.
16. A tangible, non-transitory computer readable medium, or media, storing machine readable instructions that, when executed by one or more processors, cause the one or more processors to:
cause a wireless network interface device to generate a first preamble for a first data unit that is to be transmitted via a communication channel, wherein the first preamble includes a first signal field, wherein the first signal field provides information for interpreting the first data unit, and wherein the first signal field is modulated according to a first modulation technique;
cause the wireless network interface device to generate the first data unit according to a first data unit format, wherein the first data unit includes the first preamble;
cause the wireless network interface device to generate a second preamble for a second data unit that is to be transmitted via the communication channel, wherein
the second preamble includes a second signal field,
the second signal field provides information for interpreting the second data unit, and
generating the second preamble includes modulating the second signal field according to a second modulation technique different than the first modulation technique to signal to a receiver that the second data unit is formatted according to a second data unit format different than the first data unit format;
cause the wireless network interface device to generate a data portion of the second data unit, wherein generating the data portion includes:
encoding a plurality of bits using a binary convolutional code (BCC) encoder to generate a plurality of BCC coded bits, wherein the BCC encoder continuously encodes incoming bits,
partitioning the plurality of BCC coded bits into a plurality of blocks of BCC coded bits,
encoding the plurality of blocks of BCC coded bits according to a block coding scheme to generate a plurality of block coded bits,
mapping the plurality of block coded bits to a plurality of constellation symbols, and
generating a plurality of orthogonal frequency division multiplexing (OFDM) symbols based on the plurality of constellation symbols; and
cause the wireless network interface device to generate the second data unit according to a second data unit format, wherein the second data unit includes the second preamble and the data portion;
wherein generating the first data unit according to the first format does not include using the block coding scheme.
17. The computer readable medium, or media, of claim 16 , wherein
the first preamble is generated to include a first long training field (LTF),
the second preamble is generated to include a second LTF, and
the second LTF has a duration longer than a duration of the first LTF.
18. The computer readable medium, or media, of claim 16 , wherein
the first preamble is generated to include a first short training field (STF) to facilitate detection of the first data unit,
the second preamble is generated to include a second STF to facilitate detection of the second data unit, and
the second STF has a duration longer than a duration of the first STF.
19. The computer readable medium, or media, of claim 16 , wherein encoding the plurality of blocks of BCC coded bits according to the block coding scheme comprises generating a number of copies of each bit of the plurality of BCC coded bits.
20. The computer readable medium, or media, of claim 19 , wherein encoding the plurality of blocks of BCC coded bits according to the block coding scheme comprises repeating each block of the plurality of blocks of BCC coded bits m times, wherein m is an integer greater than 1, so that m copies of each block of the plurality of blocks of BCC coded bits are included in the plurality of block coded bits.
21. The computer readable medium, or media, of claim 20 , wherein encoding the plurality of blocks of BCC coded bits according to the block coding scheme comprises, in each set of m consecutive copies of each block of the plurality of blocks of BCC coded bits, exclusive-ORing at least one of the m copies with a sequence of bits.