Nonpreemptive priority scheme for the S-MAC protocol in multimedia mobile sensor networks

S-MAC is a well-known medium access control (MAC) protocol designed for wireless sensor networks (WSNs). S-MAC uses a few novel techniques to reduce energy consumption and support self-configuration. Besides, S-MAC also achieves good scalability and collision avoidance by utilizing a combined scheduling and contention scheme. However, S-MAC does not have any priority scheme, making it unsuitable for multimedia applications and suffering from varying degree of starvation and fairness problems. In this paper, we propose a simple, efficient, but yet well-performing sliding contention window control mechanism to modify the S-MAC protocol such that priority can be supported along with the multimedia applications in multimedia mobile sensor networks. Furthermore, the proposed scheme could solve the starvation problem and alleviate the fairness problem. An analytic model is carried out to study the saturation throughput of proposed scheme. In addition, simulations were also conducted to analyze the proposed scheme and the results show that the proposed scheme is able to carry the prioritized traffic and mitigate the starvation and fairness problems.