Orthogonal frequency division multiplexing (OFDM) symbol formats for a wireless local area network (WLAN)

1. A method of generating an orthogonal frequency division multiplexing (OFDM) symbol of a data unit to be transmitted via a communication channel, the method comprising:

encoding a plurality of information bits to generate a plurality of coded bits to be included in the OFDM symbol, wherein the plurality of information bits corresponds to a first bandwidth, and wherein the OFDM symbol includes a number of data tones corresponding to a second bandwidth, the second bandwidth larger than the first bandwidth;

mapping the plurality of coded bits to a plurality constellation symbols;

mapping the plurality of constellation symbols to a first plurality of data subcarriers corresponding to a first portion of the OFDM symbol;

setting a subset of data subcarriers in the first plurality of data subcarriers to one or more predetermined values;

mapping the plurality of constellation symbols to a second plurality of data subcarriers corresponding to a second portion of the OFDM symbol;

setting a subset of data subcarriers in the second plurality of data subcarriers to one or more predetermined values; and

generating the OFDM symbol to include at least the first plurality of data subcarriers and the second plurality of data subcarriers.

2. The method of claim 1 , wherein generating the OFDM symbol further comprises including, in the OFDM symbol, one or more of (i) guard tones, (ii) direct current (DC) tones and (iii) pilot tones.

3. The method of claim 1 , wherein setting the subset of data subcarriers in the first plurality of data subcarriers to one or more predetermined values comprises setting at least one data subcarrier in the subset of data subcarriers in the first plurality of data subcarriers to a null value; and

wherein setting the subset of data subcarriers in the second plurality of data subcarriers to one or more predetermined values comprises setting at least one data subcarrier in the subset of data subcarriers in the second plurality of data subcarriers to the null value.

4. The method of claim 1 , wherein setting the subset of data subcarriers in the first plurality of data subcarriers to one or more predetermined values comprises setting at least one data subcarrier in the subset of data subcarriers in the first plurality of data subcarriers to a non-zero value; and

wherein setting the subset of data subcarriers in the second plurality of data subcarriers to one or more predetermined values comprises setting at least one data subcarrier in the subset of data subcarriers in the second plurality of data subcarriers to the non-zero value.

5. The method of claim 1 , further comprising:

mapping the plurality of constellation symbols to a third plurality of data subcarriers corresponding to a third portion of the OFDM symbol; and

setting a subset of data subcarriers in the third plurality of data subcarriers to one or more predetermined values; and

wherein generating the OFDM symbol further comprises including the third plurality of data subcarriers in the OFDM symbol.

6. The method of claim 1 , further comprising generating a preamble of a physical layer (PHY) data unit, wherein the preamble includes the OFDM symbol.

7. The method of claim 1 , further comprising generating a data portion of a physical layer (PHY) data unit, wherein the data portion includes the OFDM symbol.

8. The method of claim 1 , further comprising (i) inserting one or more additional bits into the plurality of information bits and (ii) duplicating the plurality of information bits and the additional bits, prior to encoding the information bits, to generate a plurality of duplicated bits, wherein encoding the information bits comprises encoding the plurality of duplicated bits.

9. The method of claim 1 , wherein the first bandwidth corresponds to a bandwidth B and the second bandwidth corresponds to a bandwidth mB, wherein m is an integer.

10. An apparatus, comprising:

a network interface configured to:

encode a plurality of information bits to generate a plurality of coded bits to be included in an OFDM symbol, wherein the plurality of information bits corresponds to a first bandwidth, and wherein the OFDM symbol includes a number of data tones corresponding to a second bandwidth, the second bandwidth larger than the first bandwidth,

map the plurality of coded bits to a plurality constellation symbols,

map the plurality of constellation symbols to a first plurality of data subcarriers corresponding to a first portion of the OFDM symbol,

set a subset of data subcarriers in the first plurality of data subcarriers to one or more predetermined values,

map the plurality of constellation symbols to a second plurality of data subcarriers corresponding to a second portion of the OFDM symbol,

set a subset of data subcarriers in the second plurality of data subcarriers to one or more predetermined values, and

generate the OFDM symbol to include at least the data subcarriers corresponding to the first potion and the data subcarriers corresponding to the second portion.

11. The apparatus of claim 10 , wherein the network interface is further configured to include, in the OFDM symbol, one or more of (i) guard tones, (ii) direct current (DC) tones and (iii) pilot tones.

12. The apparatus of claim 10 , wherein the network interface is further configured to

set at least one data subcarrier in the subset of data subcarriers in the first plurality of data subcarriers to a null value, and

set at least one data subcarrier in the subset of data subcarriers in the second plurality of data subcarriers to the null value.

13. The apparatus of claim 10 , wherein the network interface is further configured to

set at least one data subcarrier in the subset of data subcarriers in the first plurality of data subcarriers to a non-zero value, and

set at least one data subcarrier in the subset of data subcarriers in the second plurality of data subcarriers to the non-zero value.

14. The apparatus of claim 10 , wherein the network interface is further configured to:

map the plurality of constellation symbols to a third plurality of data subcarriers corresponding to a third portion of the OFDM symbol,

map a subset of data subcarriers in the third plurality of data subcarriers to one or more predetermined values, and

generate the OFDM symbol to further include the third plurality of data subcarriers.

15. The apparatus of claim 10 , wherein the network interface is further configured to generate a preamble of a physical layer (PHY) data unit, wherein the preamble includes the OFDM symbol.

16. The apparatus of claim 10 , wherein the network interface is further configured to generate a data portion of a physical layer (PHY) data unit, wherein the data portion includes the OFDM symbol.

17. The apparatus of claim 10 , wherein the network interface is further configured to:

insert one or more additional bits into the plurality of information bits; and

duplicate the plurality of information bits and the additional bits prior to encoding the information bits to generate a plurality of duplicated bits, wherein encoding the information bits comprises encoding the plurality of duplicated bits.

18. The apparatus of claim 11 , wherein the first bandwidth corresponds to a bandwidth B and the second bandwidth corresponds to a bandwidth mB, wherein m is an integer.