A dynamic ID management protocol for CSMA/IC in ad hoc networks

Abstract

Contention based MAC protocols are widely used in ad hoc networks because they are suitable, where no central control node exists. However, contention based MAC protocols waste much time because of frequent collisions and long contention times. Moreover, it is hard for them to fairly distribute medium access opportunities. As a result, the problem of unfair medium access may arise under normal network conditions. Recently, another contention based MAC protocol, named the Carrier Sense Multiple Access/ID Countdown (CSMA/IC) was proposed. CSMA/IC resolves medium access contention by comparing the IDs of contending nodes with a simple signaling process. Therefore, medium access collisions never happen as long as each node possesses a unique ID, and the time cost for contention may be smaller than any other contention based MAC protocols if the number of IDs is managed so as to be as small as possible. Furthermore, CSMA/IC may support fair medium access by manipulating the ID of each node properly. In this paper, we propose a novel dynamic ID management protocol which enables a node to acquire a unique ID without any message exchanges and fairly distributed the number of medium access opportunities to all contending nodes. The proposed protocol also makes the contention process of CSMA/IC efficient by dynamically managing the length of the ID field according to the network traffic. The simulation results show that the proposed ID management protocol significantly improves the aforementioned aspects of CSMA/IC MAC protocol compared to previous ID management schemes. (C) 2012 Elsevier B.V. All rights reserved.