WSEAS Transactions on Systems and Control
Print ISSN: 1991-8763, E-ISSN: 2224-2856
Volume 13, 2018
Channel Access Probability Equalization Scheme for Contention based MAC Protocols in Underwater Acoustic Sensor Networks
Author:
Abstract: Underwater acoustic sensor networks (UASNs) have become a very active research area in recent years. Compared with wireless networks, UASNs have long propagation delay of acoustic signals, which pose challenges to the design of medium access control (MAC) protocol. Most of the studies on MAC protocols focus on contention-based techniques. They are subject to long propagation delays. The long delays cause spatial-temporal uncertainty making spatial fairness a difficult problem. In the contention based MAC protocols, it is hard to provide the fairness to channel access among senders since the packet arrival time at the receiver depends on the distance between the sender and the receiver. In this paper, we propose a fair MAC protocol to solve the unfairness problem. In the proposed protocol, the packets arrive at the receiver in the transmission order regardless of the distance between the sender and the receiver. That is, all senders have the same propagation delay time. To do this, each sender computes a deferment time when sending a packet and sends it after postponing for this amount of time. A sender with close distance from the receiver has long deferment time, and a distant sender has short deferment time. The proposed protocol addresses the unfairness problem by equalizing channel access probabilities of all senders regardless of the distance. Performance evaluation is conducted using simulation, and confirms that the proposed protocol outperforms the previous protocol in terms of the fairness index.
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Pages: 88-95
WSEAS Transactions on Systems and Control, ISSN / E-ISSN: 1991-8763 / 2224-2856, Volume 13, 2018, Art. #11