Mobile Ad Hoc Networks Mac Protocol Based On Power Control Study

A mobile ad hoc network (MANET) is a self-configuring infrastructure-less network of mobile devices connected by wireless links. It does not depend on any infrastructure and centralized administration. In recent years, with the rapid development of mobile communications technology, this new network technology has attracted wide attention, and gradually be used from military to civilian. It owns some characteristics like self-organization, multi-hop, distributed management and a frequently-changed topology. The uniqueness of MANET makes it impossible to adopt the routing technologies utilized in traditional networks. Medium access control (MAC) protocols for MANET face many challenges, including energy-efficient operation, collision avoidance and spatial reuse. In this paper, we proposed a novel transmit power control based MAC protocol.Most of the previous works consider that nodes encounter interference by single interference source. However, in fact, the interference is superposition of all the interfering nodes in the network. In this paper, we present an extensional honey grid model to model the upper bound network interference and calculate the average channel rated. Then we analyze the channel performance using a Markov Chain Model. From the numerical results, we conclude that the maximum throughput and per frame minimum consumed energy occurs at an optimal transmit power which is sufficient to avoid the interference, and causes the least contention between nodes.Based on aforementioned theory results, we propose a novel TPC protocol (TPC-MAC). TPC-MAC adjusts CTS transmit power by the interference value of sending node and receiving node. Then based on the adjusted CTS range, it estimates the most interference that receiving node perhaps encounter to get the optimal DATA transmit power. This make for less interference, improved throughput and less energy consuming. For the shortcoming of IEEE 802.11 that hidden nodes within the carrier sense cannot get the accurate transmit timing of data frame, we proposed the variable-length RTS and CTS frame in order to stand for variable-length data frames. Through this way, hidden nodes can estimate the transmit timing of data frame to back off. The simulations show that TPC-MAC is valid and outperforms several proposed TPC protocols.