Selective sub-carrier processing

1. A receiver, comprising:

a receive chain operative to receive a multi-carrier signal;

a controller, the controller operative to:

determine whether a signal quality of the received multi-carrier signal is better than a predetermined signal quality, wherein the predetermined signal quality is selected to ensure that a probability of error free decoding of the received signal is greater than a predetermined threshold;

determine which of subcarriers of the multi-carrier signal not to perform receive signal processing based on a relative signal quality of each of the subcarriers after determining that the signal quality of the received multi-carrier signal is better than the predetermined signal quality.

2. The receiver of claim 1 , wherein the relative signal quality of each of the subcarriers is determined based on a comparison between a signal quality of each of the subcarriers relative to the predetermined signal quality.

3. The receiver of claim 1 , wherein the controller is further operative to determine a percentage of the subcarriers of the multi-carrier signal to perform receiver signal processing or not to determine the receiver signal processing based on a function of a selected coding rate.

4. The receiver of claim 1 , wherein the controller is further operative to:

predict a plurality of LLRs (log likelihood ratios) comprising predicting an LLR for each bit of a received symbol of each subcarrier based on the SNR of the subcarrier, wherein the LLR reflects a confidence level of the bit;

generate a de-interleaved sequence comprising de-interleaving the plurality of LLRs; and

select subcarriers of the multi-carrier signal to not to perform receiver signal processing based on avoiding a number of confidence levels in contiguous sequences of the de-interleaved sequence that are below a confidence threshold, that is above a run-length threshold.

5. The receiver of claim 1 , wherein the received signal comprises a transmit signal received though a transmission medium, wherein the transmit signal includes LDPC (low-density parity check) encoding, and wherein the controller is further operative to:

specify a parity check matrix based on the LDPC encoding;

generate a set of parity check bits, comprising multiplying a block of n input bits by the parity check matrix, wherein the input bits and any information associated with the input bits are denoted as a variable nodes, and wherein the parity check bits and any information associated with the parity check bits are denoted as check nodes;

identify a number of check nodes connected to a variable node having a reliability below a reliability threshold; and

select the subcarriers of the multi-carrier signal to perform receiver signal processing based on keeping the number of check nodes connected to a worst variable node having a reliability below a reliability threshold less than a weak node number threshold.

6. The receiver of claim 5 , wherein a reliability of a variable node is determined based on a channel estimate and noise estimate for a subcarrier corresponding to the variable node.

7. The receiver of claim 1 , wherein the receiver further includes multiple receiver antennas, and wherein a channel between the receiver and a transmitter of the receive signal is characterized by a channel matrix for each subcarrier, and further comprising selecting the subcarriers of the multi-carrier signal to perform receiver signal processing based on orthogonality of the channel matrix of each subcarrier being less than a threshold.

8. The receiver of claim 7 , wherein the orthogonality is determined based on channel and noise estimated during a preamble of the received signal.

9. The receiver of claim 1 , wherein determining whether the signal quality of the received multi-carrier signal is better than the predetermined signal quality comprises measuring an SNR of the received signal during a preamble of the received signal, and comparing the measured SNR with an approximate required SNR.

10. The receiver of claim 9 , further comprising determine whether the received signal was received through a LOS channel or a NLOS channel, and selecting the approximate required SNR based on whether the received signal was received through a LOS channel or a NLOS channel.

11. The receiver of claim 9 , wherein the controller is further operative to determine a noise profile of a channel of the received signal, and selecting the subcarriers of the multi-carrier signal to perform receiver signal processing and which subcarriers of the multi-carrier signal not to perform receiver signal processing based on the noise profile.

12. The receiver of claim 1 , wherein determining which of subcarriers of the multi-carrier signal not to perform receive signal processing is further based on MAC layer information obtained over previously received packets.

13. The receiver of claim 1 , wherein the predetermined signal quality is based on MAC layer information obtained over previously received packets.

14. A method, comprising:

determining whether a signal quality of a received multi-carrier signal is better than a predetermined signal quality, wherein the predetermined signal quality is selected to ensure that a probability of error free decoding of the received signal is greater than a predetermined threshold;

after determining that the signal quality of the received multi-carrier signal is better than the predetermined signal quality, determining which of subcarriers of the multi-carrier signal to perform receive signal processing based on a relative signal quality of each of the subcarriers.

15. The method of claim 14 , wherein the relative signal quality of each of the subcarriers is determined based on a comparison between a signal quality of each of the subcarriers relative to the predetermined signal quality.

16. The method of claim 14 , comprising additionally determining a percentage of the subcarriers of the multi-carrier signal to perform receiver signal processing based on a function of a selected coding rate.

17. The method of claim 14 , further comprising:

predicting a plurality of LLRs (log likelihood ratios) comprising predicting an LLR for each bit of a received symbol of each subcarrier based on the SNR of the subcarrier, wherein the LLR reflects a confidence level of the bit;

generating a de-interleaved sequence comprising de-interleaving the plurality of LLRs; and

selecting subcarriers of the multi-carrier signal to perform receiver signal processing based on avoiding a number of confidence levels in contiguous sequences of the de-interleaved sequence that are below a confidence threshold, that is above a run-length threshold.

18. The method of claim 14 , wherein the received signal comprises a transmit signal received though a transmission medium, wherein the transmit signal includes LDPC (low-density parity check) encoding, and further comprising

specifying a parity check matrix based on the LDPC encoding;

generating a set of parity check bits, comprising multiplying a block of n input bits by the parity check matrix;

wherein the input bits and any information associated with the input bits are denoted as a variable nodes; and

wherein the parity check bits and any information associated with the parity check bits are denoted as check nodes;

identifying number of check nodes connected to a variable node having a reliability below a reliability threshold; and

selecting the subcarriers of the multi-carrier signal to perform receiver signal processing based on keeping the number of check nodes connected to a worst variable node having a reliability below a reliability threshold less than a weak node number threshold.

19. The method of claim 18 , wherein a reliability of a variable node is determined based on a channel estimate and noise estimate for a subcarrier corresponding to the variable node.

20. The method of claim 14 , wherein a receiver that receives the receive signal includes multiple receiver antennas, and wherein a channel between the receiver and a transmitter of the receive signal is characterized by a channel matrix for each subcarrier, and further comprising selecting the subcarriers of the multi-carrier signal to perform receiver signal processing based on orthogonality of the channel matrix of each subcarrier being less than a threshold.

21. The method of claim 20 , wherein the orthogonality is determined based on channel and noise estimated during a preamble of the received signal.

22. The method of claim 14 , further comprising selecting the subcarriers of the multi-carrier signal to perform receiver signal processing and which subcarriers of the multi-carrier signal not to perform receiver signal processing based on a function of power consumed per processed subcarrier, and a probability of decoding error.

23. The method of claim 14 , wherein determining whether the signal quality of the received multi-carrier signal is better than the predetermined signal quality comprises measuring an SNR of the received signal during a preamble of the received signal, and comparing the measured SNR with an approximate required SNR.

24. The method of claim 23 , further comprising determining whether the received signal was received through a LOS channel or a NLOS channel, and selecting the approximate required SNR based on whether the received signal was received through a LOS channel or a NLOS channel.

25. The method of claim 23 , further comprising determining a noise profile of a channel of the received signal, and selecting the subcarriers of the multi-carrier signal to perform receiver signal processing and which subcarriers of the multi-carrier signal not to perform receiver signal processing based on the noise profile.

26. A method, comprising:

determining whether a signal quality of a received multi-carrier signal is better than a predetermined signal quality, wherein the predetermined signal quality is selected to ensure that a probability of error free decoding of the received signal is greater than a predetermined threshold; and

after determining that the signal quality of the received multi-carrier signal is better than the predetermined signal quality, determining which subcarriers of the multi-carrier signal not to perform receive signal processing based on a relative signal quality of each of the subcarriers.

27. A method, comprising:

determining whether a signal quality of a received multi-carrier signal is better than a predetermined signal quality, wherein the predetermined signal quality is selected to ensure that a probability of error free decoding of the received signal is greater than a predetermined threshold;

after determining that the signal quality of the received multi-carrier signal is better than the predetermined signal quality, determining which of subcarriers of the multi-carrier signal to perform receive signal processing based on a function of a selected coding rate.

28. A method, comprising:

determining whether a signal quality of a received multi-carrier signal is better than a predetermined signal quality, wherein the predetermined signal quality is selected to ensure that a probability of error free decoding of the received signal is greater than a predetermined threshold; and

after determining that the signal quality of the received multi-carrier signal is better than the predetermined signal quality, determining which subcarriers of the multi-carrier signal not to perform receive signal processing based on a function of a selected coding rate.

29. A receiver, comprising:

a receive chain operative to receive a multi-carrier signal;

a controller, the controller operative to:

determine whether a signal quality of the received multi-carrier signal is better than a predetermined signal quality, wherein the predetermined signal quality is selected to ensure that a probability of error free decoding of the received signal is greater than a predetermined threshold;

determine which of subcarriers of the multi-carrier signal to perform receive signal processing and which subcarriers not to perform receive signal processing based on a relative signal quality of each of the subcarriers after determining that the signal quality of the received multi-carrier signal is better than the predetermined signal quality.