A new multiple code channels MAC protocol in DS-CDMA wireless networks

We propose a contention based MAC protocol which will extend traditional contention based single channel wireless network such as IEEE 802.11 distributed coordination function (DCF) to be used in multiple code channels DS-CDMA wireless networks. In particular, we assume the system exist a maximum allowable simultaneously transmissions M which is dependent on the degree of multiple access interference (MAI). To control the access of multiple code channels in DS-CDMA wireless network, we define the channel regulation (CR) which is smaller than M and three channel states which are random access (RA) state, CR state and busy state respectively. The channel is in RA state, CR state and busy state whenever simultaneously transmissions are smaller than CR, between CR and M and larger than M respectively. Nodes can randomly access channel whenever they detect RA state and do p-persistent transmission while CR state is detected. If channel is detected in busy state, nodes have to run backoff algorithm to prepare next time of transmission. The simulation results show that the proposed MAC protocol algorithm performs very well.