Cross-layer optimization with retransmission diversity in wireless CDMA networks

In this paper, we propose a cross-layer optimization approach that exploits retransmission diversity in wireless CDMA communications. Conventionally, data packets that are not correctly detected are usually dropped. These dropped packets can be used to help data packet detection. By exploiting all the retransmitted packets, data packets can be correctly detected with higher probability. The proposed approach provides a way to detect the packet by canceling out the known interference and summing up the residue received signal for all the retransmissions of a packet. Higher throughput is obtained with this approach. Regarding fairness, our proposed approach performs better than the power control approach. An algorithm is brought out to find the transmission probabilities for all the users to get maximum throughput with control of fairness. Higher power efficiency, defined as a new measure to estimate cross-layer performance, is achieved. Hence power control, which is critical in wireless communications, can be relaxed with the proposed approach.