Low bandwidth PHY transmission in a wider bandwidth

An apparatus comprising:

• a network interface configured to
• determine that a first duplicate, in frequency, of one or more duplicates of a low bandwidth mode data unit will be located at an edge of a basic service set (BSS) channel having a BSS channel bandwidth, wherein
• a set of one or more component channels is collectively coextensive with the BSS channel,
• each duplicate (i) includes a plurality of orthogonal frequency division multiplexing (OFDM) tones and (ii) has a bandwidth less than a narrowest channel in the set of one or more component channels, and
• the plurality of OFDM tones in each duplicate includes one or more data tones, one or more pilot tones, and one or more guard tones, and
• generate a first transmission signal comprising the one or more duplicates, wherein the network interface is configured to generate the first transmission signal at least in part by
• in response to determining that the first duplicate will be located at an edge of the BSS channel, one or both of (i) scaling down at least one data tone of the first duplicate and (ii) zeroing out at least one data tone of the first duplicate.

A method for generating signals to be transmitted within a basic service set (BSS) channel having a BSS channel bandwidth, wherein a set of component channels is collectively coextensive with the BSS channel, the method comprising:

• generating a first duplicate, in frequency, of a low bandwidth mode data unit, wherein
• the first duplicate (i) includes a first plurality of orthogonal frequency division multiplexing (OFDM) tones and (ii) has a bandwidth less than a narrowest channel in the set of component channels, and
• the first plurality of OFDM tones includes a first set of data tones, a first set of lower-edge guard tones, and a first set of upper-edge guard tones;
• generating a second duplicate, in frequency, of the low bandwidth mode data unit, wherein
• the second duplicate (i) includes a second plurality of OFDM tones and (ii) has a bandwidth less than the narrowest channel in the set of component channels,
• the second plurality of OFDM tones includes a second set of data tones, a second set of lower-edge guard tones, and a second set of upper-edge guard tones, and
• either (i) the second set of data tones is equal to the first set of data tones with at least a highest-frequency data tone of the first set of data tones scaled down or zeroed out, or (ii) the second set of data tones is equal to the first set of data tones with at least a lowest-frequency data tone of the first set of data tones scaled down or zeroed out;
• and
• transmitting a transmission signal via at least a portion of the BSS channel, wherein
• transmitting a transmission signal via at least a portion of the BSS channel includes (i) transmitting the first duplicate via a first sub-band within the BSS channel and (ii) transmitting the second duplicate via a second sub-band within the BSS channel, and
• the second sub-band within the BSS channel is located at an upper edge of the BSS channel or a lower edge of the BSS channel.

An apparatus comprising:

• a network interface configured to
• generate a first duplicate, in frequency, of a low bandwidth mode data unit, wherein
• the first duplicate (i) includes a first plurality of orthogonal frequency division multiplexing (OFDM) tones and (ii) has a bandwidth less than a narrowest channel in a set of component channels,
• the set of component channels is collectively coextensive with a basic service set (BSS) channel having a BSS channel bandwidth, and
• the first plurality of OFDM tones includes a first set of data tones, a first set of lower-edge guard tones, and a first set of upper-edge guard tones, and
• generate a second duplicate, in frequency, of the low bandwidth mode data unit, wherein
• the second duplicate (i) includes a second plurality of OFDM tones and (ii) has a bandwidth less than the narrowest channel in the set of component channels,
• the second plurality of OFDM tones includes a second set of data tones, a second set of lower-edge guard tones, and a second set of upper-edge guard tones, and
• either (i) the second set of data tones is equal to the first set of data tones with at least a highest-frequency data tone of the first set of data tones scaled down or zeroed out, or (ii) the second set of data tones is equal to the first set of data tones with at least a lowest-frequency data tone of the first set of data tones scaled down or zeroed out, and
• transmit, via one or more antennas, a transmission signal via at least a portion of the BSS channel, wherein
• the network interface is configured to transmit the transmission signal at least in part by (i) transmitting the first duplicate via a first sub-band within the BSS channel and (ii) transmitting the second duplicate via a second sub-band within the BSS channel, and
• the second sub-band within the BSS channel is located at an upper edge of the BSS channel or a lower edge of the BSS channel.