A Highly Efficient Medium Access Protocol in Shared Wireless Medium Networks

IEEE 802.11 distributed coordination function (DCF) is the most popular medium access control (MAC) protocol in distributed wireless networks, in which the wireless medium is shared. But the throughput of the network is restrained because of collisions and the idle time slots wasted for competition. In this paper, we present a new medium access protocol with a busy tone (MABT)1. In this protocol, the backoff procedure is executed in the busy tone instead of the data channel, so there is almost no wasted time slot in the data channel. Besides, this paper also introduces a modified backoff algorithm different with that of IEEE 802.11 DCF. By this backoff algorithm, the probability of packet collision can be significantly reduced. A remarkable characteristic of this protocol is that it does not require extra transceiver for the busy tone, which doesn´t increase the hardware cost of the mobile station. We study the performance of MABT protocol through simulated experiments. The results show that MABT protocol is more efficient than the one discussed in the IEEE 802.11e task group.