A CDMA-based approach for highly efficient medium access control in mesh wireless networks

The code division multiple access (CDMA) technology has been recently introduced into mesh wireless networks for improving channel efficiency. The existing approaches, however, do not maximize the capacity of a CDMA system, because the sender transmits to one receiver only. In this paper, we explore novel approaches to allow multiple data frames be transmitted from a sender to multiple receivers simultaneously by using multi-user detection techniques and efficient power control schemes, thus maximizing network capacity and decreasing data delivery delay. More specifically, we propose two CDMA-based medium access control schemes, the PNO (Pseudo Noise Only) scheme and the PPO (PN Plus Orthogonal) scheme, for highly efficient data transmission in mesh wireless networks, especially for those networks serving as communication backbone and thus experiencing high traffic load. The performance of our proposed schemes is evaluated via simulations, and compared with IEEE 802.11 and other CDMA-based schemes under the same channel bandwidth. Our results show that PPO achieves the highest channel efficiency, because of its use of orthogonal codes for channelization. Both PPO and PNO can significantly improve network throughput and reduce packet delivery delay, without increasing signaling overhead noticeably.