Traveling pilots within single user, multiple user, multiple access, and/or MIMO wireless communications
Pilot tones are included within symbols (e.g., orthogonal frequency division multiplexing (OFDM) symbols) transmitted between wireless communication devices. The pilot tones occupy fewer than all tone locations in any given symbol, and the pilot tones occupy different respective locations within different symbols. Generally, these traveling pilots are assigned to different respective tone locations in different symbols. In total, the pilot tones deed not cover every single tone location within the symbols used to convey information between devices. Considering for example, when pilots occupy fewer than all tone locations, even among multiple symbols, a device may perform interpolation to generate a pilot tone estimate corresponding to a tone location not occupied by pilot tone within any symbol. Also, power or magnitude of the pilot tones themselves may be boosted or amplified relative to power magnitude of other tones within such symbols.
1 . A wireless communication device comprising:
a communication interface configured to receive a plurality of symbols from another wireless communication device via a wireless communication channel based on orthogonal frequency division multiplexing (OFDM) signaling, wherein a symbol of the plurality of symbols includes a plurality of sub-carriers, wherein a subset of sub-carriers of the plurality of sub-carriers includes pilot tones that are distributed in a pattern among the plurality of sub-carriers, and wherein, from symbol to symbol for at least some of the plurality of symbols, the pattern is different such that, for the plurality of symbols, a desired number of the plurality of plurality of sub-carriers have included pilot tones; and
a processor configured to process the pilot tones of the plurality of symbols to generate a channel estimate of the wireless communication channel
2 . The wireless communication device of claim 1 further comprising:
the processor configured to:
perform interpolation using at least some of the pilot tones to generate at least one estimated pilot tone for at least one tone sub-carrier not included in the subset of sub-carriers of the plurality of symbols; and
include the at least one estimated pilot tone in the processing of the pilot tones to generate the channel estimate of the wireless communication channel.
3 . The wireless communication device of claim 1 further comprising:
the communication interface configured to receive the pilot tones of one of the plurality of symbols at a higher power level than a power level of data tones of the one of the plurality of symbols.
4 . The wireless communication device of claim 1 further comprising:
the communication interface configured to receive the plurality of symbols via a plurality of spatial time streams.
5 . The wireless communication device of claim 1 further comprising:
the processor configured to employ a formula that is a function of a number of pilot tones of the plurality of symbols to determine, from symbol to symbol for at least some of the plurality of symbols, the pattern of pilot tones.
6 . The wireless communication device of claim 1 , wherein the plurality of symbols is further based on space time block coding (STBC) signaling.
7 . The wireless communication device of claim 1 further comprising:
the processor configured to process the pilot tones of a first symbol of the plurality of symbols to generate a first preliminary channel estimate and the pilot tones of a second symbol of the plurality of symbols to generate a second preliminary channel estimate for use in generating the channel estimate of the wireless communication channel.
8 . The wireless communication device of claim 1 further comprising:
circuitry to function as a wireless station (STA) or a smart meter station (SMSTA), wherein the other wireless communication device includes an access point (AP).
9 . A wireless communication device comprising:
a communication interface configured to receive a plurality of symbols from another wireless communication device via a wireless communication channel based on orthogonal frequency division multiplexing (OFDM) signaling and via a plurality of spatial time streams, wherein a symbol of the plurality of symbols includes a plurality of sub-carriers, wherein a first plurality of pilot tones within a first spatial stream of the plurality of spatial time streams are located at a first noncontiguous tone location subset within a first symbol of the plurality of symbols and a second plurality of pilot tones within a second spatial stream of the plurality of spatial time streams are located at a second noncontiguous tone location subset within a second symbol of the plurality of symbols that is offset with respect to the first noncontiguous tone location subset based on a formula that is a function of a number of pilot tones of the plurality of symbols; and
a processor configured to process the first plurality of pilot tones and the second plurality of pilot tones to generate a channel estimate of the wireless communication channel.
10 . The wireless communication device of claim 9 further comprising:
the processor configured to:
perform interpolation using at least one of the first plurality of pilot tones and the second plurality of pilot tones to generate at least one estimated pilot tone for at least one tone sub-carrier not included in the subset of sub-carriers of the plurality of symbols; and
include the at least one estimated pilot tone in the processing of the pilot tones to generate the channel estimate of the wireless communication channel.
11 . The wireless communication device of claim 9 further comprising:
the communication interface configured to receive at least one of the first plurality of pilot tones and the second plurality of pilot tones of one of the plurality of symbols at a higher power level than a power level of data tones of the one of the plurality of symbols.
12 . The wireless communication device of claim 9 further comprising:
the processor configured to process the first plurality of pilot tones to generate a first preliminary channel estimate and the second plurality of pilot tones to generate a second preliminary channel estimate for use in generating the channel estimate of the wireless communication channel.
13 . The wireless communication device of claim 9 further comprising:
circuitry to function as a wireless station (STA) or a smart meter station (SMSTA), wherein the other wireless communication device includes an access point (AP).
14 . A method for execution by a wireless communication device, the method comprising:
via a communication interface of the wireless communication device, receiving a plurality of symbols from another wireless communication device via a wireless communication channel based on orthogonal frequency division multiplexing (OFDM) signaling, wherein a symbol of the plurality of symbols includes a plurality of sub-carriers, wherein a subset of sub-carriers of the plurality of sub-carriers includes pilot tones that are distributed in a pattern among the plurality of sub-carriers, and wherein, from symbol to symbol for at least some of the plurality of symbols, the pattern is different such that, for the plurality of symbols, a desired number of the plurality of plurality of sub-carriers have included pilot tones; and
processing the pilot tones of the plurality of symbols to generate a channel estimate of the wireless communication channel.
15 . The method of claim 14 further comprising:
performing interpolation using at least some of the pilot tones to generate at least one estimated pilot tone for at least one tone sub-carrier not included in the subset of sub-carriers of the plurality of symbols; and
including the at least one estimated pilot tone in the processing of the pilot tones to generate the channel estimate of the wireless communication channel.
16 . The method of claim 14 further comprising:
receiving the pilot tones of one of the plurality of symbols at a higher power level than a power level of data tones of the one of the plurality of symbols.
17 . The method of claim 14 further comprising:
receiving the plurality of symbols via a plurality of spatial time streams.
18 . The method of claim 14 further comprising:
employing a formula that is a function of a number of pilot tones of the plurality of symbols to determine, from symbol to symbol for at least some of the plurality of symbols, the pattern of pilot tones.
19 . The method of claim 14 , wherein the plurality of symbols is further based on space time block coding (STBC) signaling.
20 . The method of claim 14 further comprising:
performing wireless station (STA) or smart meter station (SMSTA) functionality to communicate with the other wireless communication device that is an access point (AP).