Abstract: An efficient MAC protocol is one of the keys for long-time working and high-performance communication of WSN. There are several mechanisms for wireless channel allocation, such as Contention-base Random Access, TDMA (Time Division Multiple Acccss),FDMA(Frcqucncy Division Multiple Access) and CDMA(Codc Division Multiple Access). According to WSN, the CSMA-based MAC protocol has disadvantages like idle listening and collision; the TD-MA-based and FDMA-based MAC protocol has low scalability problem; the CDMA-based MAC protocol has the problem of additional power consumption. After analyzing energy model of the pure TDMA, pure CDMA and hybrid TD-MA/CDMA，the paper presented a hybrid TDMA/CD MA MAC protocol based on cluster, which can solve the low latency and the conflict with interference. The protocol proposes the cluster nodes use TDMA and the cluster heads use CDMA. MAC could achieve collision avoidance and low latency in clusters, and do not have to ensure high accuracy synchronization between each cluster, so that the scalability of the sensor network would be enhanced.

Key words: Wireless sensor network, Channel allocation,TDMA, CDMA