A method comprising: generating a first data unit corresponding to a first physical layer, PHY, mode, wherein generating the first data unit includes (a) forward error correction, FEC, encoding a first plurality of information bits, wherein FEC encoding the first plurality of information bits is performed according to a first modulation and coding scheme, MCS, selected from a plurality of MCSs of the first PHY mode, wherein the first MCS corresponds to a lowest throughput level of a plurality of throughput levels of the first PHY mode, (b) mapping the FEC-encoded first plurality of information bits to a first plurality of constellation symbols without block-encoding the FEC-encoded first plurality of information bits, and (c) generating a first plurality of orthogonal frequency division multiplexing, OFDM, symbols to include the first plurality of constellation symbols, wherein the first plurality of OFDM symbols (i) utilizes a first tone spacing, and (ii) includes a first number of non-zero tones collectively spanning a first bandwidth; and generating a second data unit corresponding to a second PHY mode, wherein generating the second data unit includes (a) FEC encoding a second plurality of information bits, wherein FEC encoding the second plurality of information bits is performed according to the first MCS that corresponds to the lowest throughput level of the first PHY mode, (b) block encoding the FEC-encoded second plurality of information bits to further reduce the lowest throughput level of the first PHY mode, (c) mapping the block-encoded second plurality of information bits to a second plurality of constellation symbols, and (d) generating a second plurality of OFDM symbols to include the second plurality of constellation symbols, wherein the second plurality of OFDM symbols (i) utilizes the first tone spacing, and (ii) includes a second number of non-zero tones collectively spanning a second bandwidth, the second number of non-zero tones is less than the first number of non-zero tones, and the second bandwidth is less than the first bandwidth. generating a first data unit corresponding to a first physical layer, PHY, mode, wherein generating the first data unit includes (a) forward error correction, FEC, encoding a first plurality of information bits, wherein FEC encoding the first plurality of information bits is performed according to a first modulation and coding scheme, MCS, selected from a plurality of MCSs of the first PHY mode, wherein the first MCS corresponds to a lowest throughput level of a plurality of throughput levels of the first PHY mode, (b) mapping the FEC-encoded first plurality of information bits to a first plurality of constellation symbols without block-encoding the FEC-encoded first plurality of information bits, and (c) generating a first plurality of orthogonal frequency division multiplexing, OFDM, symbols to include the first plurality of constellation symbols, wherein the first plurality of OFDM symbols (i) utilizes a first tone spacing, and (ii) includes a first number of non-zero tones collectively spanning a first bandwidth; and (a) forward error correction, FEC, encoding a first plurality of information bits, wherein FEC encoding the first plurality of information bits is performed according to a first modulation and coding scheme, MCS, selected from a plurality of MCSs of the first PHY mode, wherein the first MCS corresponds to a lowest throughput level of a plurality of throughput levels of the first PHY mode, (b) mapping the FEC-encoded first plurality of information bits to a first plurality of constellation symbols without block-encoding the FEC-encoded first plurality of information bits, and (c) generating a first plurality of orthogonal frequency division multiplexing, OFDM, symbols to include the first plurality of constellation symbols, wherein the first plurality of OFDM symbols (i) utilizes a first tone spacing, and (ii) includes a first number of non-zero tones collectively spanning a first bandwidth; and generating a second data unit corresponding to a second PHY mode, wherein generating the second data unit includes (a) FEC encoding a second plurality of information bits, wherein FEC encoding the second plurality of information bits is performed according to the first MCS that corresponds to the lowest throughput level of the first PHY mode, (b) block encoding the FEC-encoded second plurality of information bits to further reduce the lowest throughput level of the first PHY mode, (c) mapping the block-encoded second plurality of information bits to a second plurality of constellation symbols, and (d) generating a second plurality of OFDM symbols to include the second plurality of constellation symbols, wherein the second plurality of OFDM symbols (i) utilizes the first tone spacing, and (ii) includes a second number of non-zero tones collectively spanning a second bandwidth, the second number of non-zero tones is less than the first number of non-zero tones, and the second bandwidth is less than the first bandwidth. (a) FEC encoding a second plurality of information bits, wherein FEC encoding the second plurality of information bits is performed according to the first MCS that corresponds to the lowest throughput level of the first PHY mode, (b) block encoding the FEC-encoded second plurality of information bits to further reduce the lowest throughput level of the first PHY mode, (c) mapping the block-encoded second plurality of information bits to a second plurality of constellation symbols, and (d) generating a second plurality of OFDM symbols to include the second plurality of constellation symbols, wherein