Sequential opportunistic decoding for spread spectrum wireless networks

In general, the instantaneous signal-to-interference-plus-noise ratio varies across a received frame. This variation is considerable in wireless systems in particular, due to the time-varying nature of wireless channels. To exploit this variation, we divide the received frame into a number of constituent mini-frames, each mini-frame containing the received versions of every symbol in the frame. We select a subset of these mini-frames, combine them and attempt to decode the frame. If this attempt fails, we select another subset of the mini-frames and make another attempt. We continue the process until the frame is decoded without errors or all predetermined subsets of the mini-frames have been exhausted. We implement the proposed protocol in a CDMA system. Our study shows that deploying our proposed protocol in a CDMA system results in a significant reduction in the frame error rate.