Increasing the robustness of channel estimates derived through sounding for WLAN
View Patent ↗A plurality of training signal sets are transmitted. Each training signal set includes information sufficient to determine a channel estimate corresponding to a communication channel from a first station to a second station. A refined channel estimate is determined based on reception of the plurality of training signal sets.
1. A method, comprising:
receiving a plurality of training signal sets from a first station, wherein each received training signal set includes information sufficient to determine a channel estimate corresponding to a communication channel from the first station to a second station;
determining a plurality of individual channel estimates based on the plurality of received training signal sets; and
determining a refined channel estimate corresponding to the communication channel from the first station to the second station based on a mathematical combination of the plurality of individual channel estimates.
2. A method according to claim 1 , further comprising transmitting to the first station a single request to transmit the plurality of training signal sets.
3. A method according to claim 1 , further comprising transmitting to the first station a plurality of respective requests to transmit the plurality of training signal sets.
4. A method according to claim 1 , wherein determining the refined channel estimate comprises determining the channel estimate based on a weighted combination of the plurality of individual channel estimates.
5. A method according to claim 4 , wherein determining the refined channel estimate based on the weighted combination of the plurality of individual channel estimates comprises utilizing a plurality of different weights.
6. A method according to claim 1 , further comprising transmitting the channel estimate to the first station.
7. A method according to claim 1 , further comprising determining a channel estimate corresponding to a communication channel from the second station to the first station based on the refined channel estimate corresponding to the communication channel from the first station to the second station.
8. A method according to claim 1 , wherein each training signal set is included in a packet.
9. A method according to claim 1 , wherein determining the refined channel estimate comprises determining the refined channel estimate only after the plurality of training signal sets has been received.
10. A method according to claim 1 , wherein determining the refined channel estimate comprises incrementally determining the refined channel estimate after each training signal set is received.
11. A method according to claim 10 , further comprising utilizing an incrementally determined refined channel estimate after each training signal set is received.
12. A method according to claim 1 , further comprising utilizing the refined channel estimate only after the plurality of training signal sets has been received.
13. A method, comprising:
transmitting a plurality of training signal sets to a first station, wherein each training signal set includes information sufficient for determining a channel estimate corresponding to a communication channel from a second station to the first station;
receiving respective individual channel estimates from the first station in response to each of the plurality of training signal sets; and
determining a refined channel estimate corresponding to the communication channel from the second station to the first station based on a mathematical combination of the plurality of individual channel estimates.
14. A method according to claim 13 , wherein determining the refined channel estimate comprises determining the refined channel estimate based on a weighted combination of the plurality of individual channel estimates.
15. A method according to claim 14 , wherein determining the refined channel estimate based on the weighted combination of the plurality of individual channel estimates comprises utilizing a plurality of different weights.
16. A method according to claim 13 , wherein each training signal set is included in a packet.
17. A method according to claim 13 , wherein determining the refined channel estimate comprises determining the refined channel estimate only after the plurality of individual channel estimates has been received.
18. A method according to claim 13 , wherein determining the refined channel estimate comprises incrementally determining the refined channel estimate after each individual channel estimate is received.
19. A method according to claim 18 , further comprising utilizing an incrementally determined channel estimate after each individual channel estimate is received.
20. A method according to claim 13 , further comprising utilizing the refined channel estimate only after the plurality of individual channel estimates has been received.
21. A first wireless transceiver, comprising:
a plurality of antennas;
a pre-coding processor coupled to the plurality of antennas;
a modulation unit coupled to the pre-coding processor; and
a channel determination unit configured to
generate a plurality of individual channel estimates based on a plurality of received training signal sets received from a second wireless transceiver, wherein each received training signal set includes information sufficient to determine a channel estimate corresponding to a communication channel from the second wireless transceiver to the first wireless transceiver, and
determine a refined channel estimate based on a mathematical combination of the plurality of individual channel estimates.
22. A first wireless transceiver according to claim 21 , wherein the refined channel estimate is a forward channel estimate, and wherein the channel determination unit is configured to:
determine a reverse channel estimate based on the plurality of received training signal sets; and
determine the forward channel estimate based on the reverse channel estimate.
23. A first wireless transceiver according to claim 21 , wherein the channel determination unit is configured to determine the refined channel estimate based on a weighted combination of the plurality of individual channel estimates.
24. A first wireless transceiver according to claim 23 , wherein the channel determination unit is configured to utilize a plurality of different weights.
25. A first wireless transceiver according to claim 21 , wherein the channel determination unit is configured to determine the refined channel estimate iteratively after each received training signal set is received.
26. A first wireless transceiver according to claim 25 , further comprising a beamsteering matrix calculation unit configured to utilize the iteratively determined refined channel estimate after each training signal set is received.
27. A first wireless transceiver according to claim 21 , further comprising a beamsteering matrix calculation unit configured to utilize the refined channel estimate only after the plurality of received training signal sets has been received.
28. A first wireless transceiver according to claim 21 , further comprising a controller configured to cause the first wireless transceiver to transmit to the second wireless transceiver a single request to transmit a plurality of training signal sets.
29. A first wireless transceiver according to claim 21 , further comprising a controller configured to cause the first wireless transceiver to transmit to the second wireless transceiver a plurality of respective requests to transmit a plurality of training signal sets.
30. A first wireless transceiver, comprising:
a plurality of antennas;
a pre-coding processor coupled to the plurality of antennas;
a modulation unit coupled to the pre-coding processor;
a controller coupled to the modulation unit to cause a plurality of training signal sets to be transmitted from the first wireless transceiver to a second wireless transceiver, wherein each training signal set includes information sufficient to determine a channel estimate corresponding to a communication channel from the first wireless transceiver to a second wireless transceiver; and
a channel determination unit to generate a refined channel estimate based on a mathematical combination of a plurality of respective individual channel estimates received from the second wireless transceiver in response to each of the plurality of training signal sets.
31. A first wireless transceiver according to claim 30 , wherein the channel determination unit is configured to determine the refined channel estimate based on a weighted combination of the plurality of individual channel estimates.
32. A first wireless transceiver according to claim 31 , wherein the channel determination unit is configured to utilize a plurality of different weights.
33. A first wireless transceiver according to claim 30 , wherein the channel determination unit is configured to determine the refined channel estimate iteratively after each individual channel estimate is received.
34. A first wireless transceiver according to claim 33 , further comprising a beamsteering matrix calculation unit configured to utilize the iteratively determined refined channel estimate after each individual channel estimate is received.
35. A first wireless transceiver according to claim 30 , further comprising a beamsteering matrix calculation unit configured to utilize the refined channel estimate only after the plurality of individual channel estimates has been received.
36. A first wireless transceiver according to claim 30 , wherein the controller is configured to determine a signal-to-noise ratio (SNR) associated with the communication channel;
wherein the controller is configured to cause the plurality of training signal sets to be transmitted only if it is determined that the SNR meets a criterion.