Patent ID: 8948283
Filing Date: 2015-02-03
Classification: H04L,H04W

Abstract:
1. A method for generating a null data packet (NDP) sounding packet for transmission via a communication channel, the method comprising: generating a signal field, wherein generating the signal field comprises including in the signal field a sub-field that indicates a number of spatial or space-time streams corresponding to the NDP sounding packet, wherein the sub-field corresponds to a portion of the signal field that, when included in regular packets that are not NDP sounding packets, is used for a purpose other than indicating a number of spatial or space-time streams; generating one or more long training fields; modulating the signal field and the long training fields using a plurality of orthogonal frequency division multiplexing (OFDM) symbols, wherein symbol duration of each OFDM symbol of the plurality of OFDM symbols is at least 8 μs; and generating the NDP sounding packet to include the plurality of OFDM symbols, wherein the NDP sounding packet omits a data payload portion.