Research On Dual Busy Tone MAC Protocol In Ad Hoc Network

Ad hoc network is a new kind of peer-to-peer wireless communication network, it has becomeone of the hot spots in wireless communication field for its charateristics as flexible and not easily bedestroyed. Medium access control protocol is one of the key technologies which decide how to use thewireless channel shared between nodes in Ad hoc network. Single-channel MAC protocols in Ad hocnetwork such as IEEE802.11DCF will bring hidden and exposed terminal problems which will affectthe network performance directly. Dual busy tone medium access control protocol that takesadvantages of the channel division technology and busy-tone mechanism could solve the hiddenterminal problem and particial exposed problem, it could also significantly improve the untilizationrate of channel. As a consequence, we emphatically research on the DBTMA protocol in this paper.On account of the power consume and fairness problem in DBTMA protocol, we respectively applypower control mechanism and new backoff algorithm to improve the power consume, fairness andthroughput performance of the protocol. The main work of this paper is given as follows:Firstly we give a detailed introduction of the existing power control mechanism of Ad hocnetwork and apply the power control mechanism to the DBTMA protocol, design the dual busy tonepower control protocol. The DBTPC protocol determines the transmitting power of nodes by adaptivepower control technique and the basic power control method. It could also avoid interference fromlarger range. Simulation proves that this protocol could effectively reduce the average power consumeof nodes by38%~40%while improve the throughput performance of network in a certain degree.Secondly we analyze the fairness of DBTMA protocol and find it has serious unfairnessproblem. In this paper we design a backoff algorithm based on busy-tone awaring. The interferenceperceived by monitoring the transmitting and receiving busy-tones could help dertermine the value ofcontention window. This algorithm could avoid the nodes which succeeded in last contentioncontinuously occupying the shared channel, at the same time, impove the competitiveness of thecontinuous failed nodes. Simulation shows that the BAI algorithm could impove the networkperformance of fairness in channel accessing, average throughput and average end-to-end delay.