802.11网络中基于博弈理论的可变带宽信道分配研究

Variable-Width Channel Allocation Based on Game Theory in 802.11 Networks

802.11网络中节点的理性和自私性导致可变带宽信道分配的低公平性、低负载均衡性及低社会效率问题.基于非合作博弈理论将可变带宽信道分配问题建模成策略型博弈模型.首先,给出问题的纳什均衡分配策略,证明了纳什均衡点的存在;然后,针对纳什均衡策略社会效率低的问题,提出一种基于支付的激励机制,使可变带宽信道分配过程收敛到占优决策均衡状态,从而系统整体吞吐量性能达到全局最优;并分析了上述两种策略的公平性和负载均衡问题;最后,给出达到纳什均衡和全局最优状态的可变带宽信道分配算法.仿真结果表明,纳什均衡策略能够获得好的公平性,而全局最优策略的负载均衡和社会效率性能要优于纳什均衡策略.

In 802.11 wireless networks, the nodes which belong to different networks are rational and selfish, which results in low fairness, low load-balance and low social efficiency of variable-width channel allocation mechanisms. In this paper, we study the variable-width channel allocation problem from a non-cooperative game-theoretic point of view in 802.11 wireless networks. Firstly, we model the variable-width channel allocation problem as a strategic game, and prove the existence of the Nash equilibrium （NE） strategy, and show the conditions that guarantee the variable-width channel allocation process converges to the NE state. Secondly, we propose an incentive mechanism based on payment to cope with the social inefficient problem of the NE strategy. The incentive mechanism influences the nodes＇ allocation behavior and enables the system to converge to the dominant strategy equilibrium （DSE） state, in which the performance of the whole system attains the global optimality in terms of system-wide aggregate throughput. Meanwhile, we consider and analyze the fairness and load-balance of both two strategies. Finally, we propose two variable-width channel allocation algorithms to achieve the NE and the DSE states. We have evaluated the efficiency of two algorithms and discussed the influence of the proposed schemes on the system-wide throughput. Simulation results show that the NE strategy achieves good fariness, and the DSE strategy rworks better than the NE strategy in terms of 10ad-balance and social efficiency.