Measurements for performance degradation of adaptive modulation scheme caused by channel quality estimation error

The effectiveness of adaptive modulation is affected by the accuracy of channel quality estimation. The authors attempt to find a simple way to measure the performance degradation of adaptive modulation schemes caused by channel quality estimation error without considering the details of specific multimedia information to be transmitted. With their approach, the effect of channel quality estimation error on the performance of the adaptive modulation scheme is analysed using four proposed parameters: extra bit-error-rate cost (EBC), potential theoretical channel capacity loss (PTCCL), average system EBC and average system PTCCL. Experiments are performed using a 4-mode adaptive modulation scheme and the tradeoff between the proposed parameters is discussed. It is shown that the effects of channel quality estimation error on average system performance are not apparent. However, it is still necessary to keep the estimation error small in order to keep a good instantaneous performance of the system.