US Patent 7826521 Rate adaptation using error vector magnitude

Rate adaptation is accurately provided by using an average SNR technique, a predicted PER technique, or an EVM to PER mapping technique. An average SNR is computed by averaging EVM values in a particular domain. Using the computed average SNR, an optimized rate is determined. The predicted PER technique includes computing EVM values for a current packet, determining an average BER using these EVM values for each data rate, determining an average SNR from this average BER, using the average SNR and a PER versus SNR curve to determine the predicted PER for each data rate, and using a data rate and the predicted PER to compute the predicted throughput for that data rate. In the last technique, an EVM is mapped to a packet error rate (PER) for each data rate. A throughput is computed for each data rate and PER. A data rate with a high throughput is selected.