Abstract: How to adapt parameters in non-saturated conditions to dynamic network conditions is a main problem of adaptive access mechanism in WLANs. Based on channel status information, the paper proposes an adaptive non-saturation access mechanism, which presents a linear adjustment rule of access mechanism. By sensing and counting channel busy status, a node adjusts contention window linearly and doesn’t limit the ranges of contention window, which embodies the channel congestion status. The adaptive access mechanism separates the adjustment rule of parameters from the status of data transmissions, which can decrease collision probability of channel and improve network performance. The simulation results demonstrate the validity and good scalability of the proposed access mechanism.

Key words: IEEE 802.11, medium access control, non-saturation condition, backoff algorithm, channel status information

摘要： 调整参数以适应动态的网络环境，提供非饱和条件下的自适应接入方案，是无线局域网通信的研究热点。基于信道状态信息，设计线性调整接入参数规则，提出非饱和条件自适应接入方案。节点首先感知并统计信道繁忙状态数据，然后采用线性方式调整竞争窗口大小，能有效降低信道碰撞概率，提高网络性能。方案中接入参数调整体现了信道拥塞状态，解除了接入参数调整对于数据传输状态的依赖，取消了固定竞争窗口范围对性能的影响。仿真结果进一步验证算法有效性和良好的可扩展性能。

关键词: IEEE 802.11, 媒介访问控制, 非饱和条件, 退避算法, 信道状态信息