移动自组网媒体接入控制协议吞吐量与公平性均衡设计

Design of medium access control protocol tradeoff between throughput and fairness in MANET

针对移动自组网媒体接入控制(MAC)协议高吞吐量、低公平性的失衡问题,提出一种基于最优接入概率的简化协议MAC-FT。首先推导公平条件下最优吞吐量与节点数、节点数与空闲接入概率的定量关系,设计空闲接入概率评估模型,利用李雅普诺夫漂移函数证明模型的可行性和稳定性;其次利用自回归滑动平均(ARMA)模型滤波实现空闲时隙接入概率的计算,并通过比例积分控制器(PIC)完成动态控制;最后综合分析吞吐量和公平性等性能。实验结果表明MAC-FT公平索引值为0.98,吞吐量为6.15 Mb/s,接近最优值1和5.85 Mb/s,比渐进最佳回退(AOB)、空闲感知(IS)、协议分布式协调(DCF)、改进协议启发式缓变协议(GDCF)性能更优,实现吞吐量和公平性的均衡。

Since Mobile Ad Hoc NETwork （MANET） has imbalance of high throughput but low fairness, a novel Medium Access Control （MAC） protocol named MAC-FT was proposed. Firstly, two expressions were deduced and focus on relationship of optimal throughput and nodes＇ number, and relationship of idle slot probability and nodes＇ number. On the basis of this, idle slot probability model was developed, whose feasibility and stability were proved based on Lyapunov drift. Secondly, idle slot probability computation was implemented through Auto-Regressive and Moving Average （ARMA） model filter scheme and its dynamics was controlled by Proportional Integral Controller （PIC） model. Finally, performance of MAC- FT was analyzed synthetically. Results show that, fairness index and throughput reached to 0.98 and 6.15 Mb/s respectively, which were similar to optimal value 1 and 5.85 Mb/s. Therefore, performance of MAC-FF is better than Asymptotically Optimal Backoff （AOB）, Idle Sense （IS）, Distribution Coordination Function （DCF）, and Gentle DCF （GDCF）, and itimproves balance of throughput and fairness.