A novel error control scheme for CDMA wireless LANs

A hybrid-ARQ error control protocol for asynchronous code division multiple access (CDMA) local area networks is proposed and its performance is evaluated. Assuming a peer-to-peer type but with a base station for power control, each unit can communicate directly and the near-far effect is eliminated. Packets are convolutionally encoded before modulation. The receiver has a hard-decision decoder using a modified Viterbi decoding algorithm, and may decide to request retransmission under a threshold criterion of the algorithm. The network is modeled with several interactive continuous-time absorbing Markov chains. Degradation of throughput may be expected but this can be reasonably controlled by adjusting the threshold level. This hybrid scheme offers a more flexible set of parameters from which individual users can choose, thus it can be customized to fit the individual reliability level needs for each receiver