Study On Power Controlled MAC Protocol In Ad Hoc Network

A mobile Ad Hoc network (MANET) is a collection of wireless mobile nodesdynamically forming a temporary multiple-hop network without the use of any centralcontroller or existing net-infrastructure.Under the premise of ensuring a certain quality of communication, the idea ofpower controlled schemes is to adjust the transmission power optimally and reduce it asmuch as possible. Introducing power controlled schemes in Ad Hoc network, can notonly debasing the network energy wastage, but also reducing the interference withnearby nodes. Channels can be aggressively reused, which can enhance the capability ofentire network.In this paper, former PCMA protocol is deeply researched. An improved PCMAprotocol (S-PCMA) which combines DBTMA protocol with DWDB protocol isproposed. The essential idea of S-PCMA protocol is using the sender-initiated powercontrolled busy tone as a mechanism for blocked nodes to announce the access request.A problem that the probability of successful communications between different nodes ismonotonically decreasing with respect to the increased distance and traffic load isabated. Integrating with DWDB scheme, S-PCMA protocol can effectively solve theunfair channel access problem and nodes blocked problem in communication networks.Through analysis and simulation, we demonstrate that the S-PCMA protocol is ableto balance the tradeoff between fair channel access and throughput, and is thereforemore flexible than both the traditional dual busy tone and power controlled MACprotocols.