Method and system for channel estimation in burst mode
The present invention is directed to a system and method for channel estimation for a communication channel such as, for example, that found in a wireless communication network. One or more channel estimates or channel observables can be combined to compute a refined channel estimate, for example, when the channel estimates or channel observables are from the same channel.
1. A method of channel estimation comprising:
a first network device receiving a packet comprising a sequence of packet frame synchronization symbols and a sequence of channel estimation symbols transmitted on a channel by a second network device;
the first network device receiving an observable from a channel estimation or packet frame synchronization symbol of the received packet;
the first network device generating a first channel estimate for the channel based on the received observable; and
the first network device combining the first channel estimate for the channel with a previously generated channel estimate for the channel;
wherein the previously generated channel estimate was generated based on a previously received observable from a previously received channel estimation or packet frame synchronization symbol of a previously received packet transmitted on the channel by the second network device; and
wherein the received packet and previously received packet are packets transmitted in a burst of packets during a burst mode of communications between the first network device and the second network device.
2. The method of claim 1 , wherein the combination of channel estimates comprises an average of the channel estimates.
3. The method of claim 1 , wherein the combination of the channel estimates comprises applying a weighting factor to the channel estimates.
4. The method of claim 1 , wherein the combination of the channel estimates comprises applying an aging factor to the channel estimates.
5. The method of claim 1 , wherein the combination of the channel estimates comprises combining an initial channel estimate value with a seed value.
6. The method of claim 1 , wherein the combination of the channel estimates comprises allowing an initial channel estimate value to pass through the system without being combined with another channel estimate value.
7. The method of claim 1 , wherein the channel estimates comprise channel estimates from an identical channel.
8. The method of claim 1 , wherein the channel estimates comprise channel estimates from a time-varying channel.
9. The method of claim 1 , wherein the channel estimates comprise channel estimates from substantially correlated channels.
10. The method of claim 1 , wherein burst mode is determined using a flag in a physical layer header.
11. The method of claim 1 , wherein burst mode is determined from a source identification.
12. A method of channel estimation comprising:
a first network device receiving a packet comprising a sequence of packet frame synchronization symbols and a sequence of channel estimation symbols transmitted on a channel by a second network device;
the first network device receiving an observable from a channel estimation or packet frame synchronization symbol of the received packet;
the first network device combining the observable with a previously received observable from a previously received channel estimation or packet frame synchronization symbol transmitted on the channel by the second network device; and
the first network device generating a channel estimate based on the combined observables;
wherein the received packet and previously received packet are packets transmitted in a burst of packets during a burst mode of communications between the first network device and the second network device.
13. The method of claim 12 , wherein the combination of observables comprises a simple average of the channel estimates.
14. The method of claim 12 , wherein the combination of the observables comprises applying a weighing factor to the channel estimates.
15. The method of claim 12 , wherein the combination of the observables comprises applying an aging factor to the channel estimates.
16. The method of claim 12 , wherein the combination of the observables comprises combining an initial observable value with a seed value.
17. The method of claim 12 , wherein the combination of the observables comprises allowing an initial observable value to pass through the system without being combined with another observable value.
18. The method of claim 12 , wherein the channel estimates comprise channel estimates from an identical channel.
19. The method of claim 12 , wherein the channel estimates comprise channel estimates from a time-varying channel.
20. The method of claim 12 , wherein the channel estimates comprise channel estimates from substantially correlated channels.
21. The method of claim 12 , wherein burst mode is determined using a flag in a physical layer header.
22. The method of claim 12 , wherein burst mode is determined from a source identification.
23. An electronic receiver of a first network device comprising:
a receiver configured to receive a packet comprising a sequence of packet frame synchronization symbols and a sequence of channel estimation symbols transmitted on a channel by a second network device;
a channel combination system configured to combine observables or channel estimates wherein the observables or channel estimates are from the same channel; and
an estimator, coupled to the channel combination device and configured to convert an observable into a channel estimate, wherein the observables comprise a given observable from a channel estimation or packet frame synchronization symbol of the received packet and a previously received observable from a previously received channel estimation or packet frame synchronization symbol of a previously received packet and the channel estimates comprise a given channel estimate for the channel and a previously generated channel estimate for the channel; and
wherein the received packet and previously received packet are packets transmitted in a burst of packets during a burst mode of communications between the first network device and the second network device.
24. The electronic receiver of claim 23 , wherein the channel combination system comprises a channel estimation combination system configured to combine channel estimates, wherein the estimator is coupled to the channel estimation combination system and configured to convert an observable into a first channel estimate for input into the channel estimation combination system.
25. The electronic receiver of claim 23 , wherein the channel combination system comprises a channel observable combination system configured to combine channel observables, and wherein the estimator is coupled to the channel observable combination system and configured to convert the combined channel observable output from the channel observable combination system into a channel estimate.
26. The electronic receiver of claim 23 , wherein the estimator comprises an LS estimator.
27. The electronic receiver of claim 23 , wherein the estimator comprises a low-pass filtered least squares (LS) estimator.
28. The electronic receiver of claim 23 , wherein the estimator comprises an least minimum mean square error (LMMSE) estimator.
29. The electronic receiver of claim 28 , wherein an LS estimate is used to initialize the LMMSE estimator.
30. The electronic receiver of claim 23 , wherein the observables or channel estimates comprise observables or channel estimates from an identical channel.
31. The electronic receiver of claim 23 , wherein the observables or channel estimates comprise observables or channel estimates from a time-varying channel.
32. The electronic receiver of claim 23 , wherein the observables or channel estimates comprise observables or channel estimates from substantially correlated channels.