Abstract: Utilization rate of wireless channel can be efficiently improved by designing appropriate collision resolution mechanism. Aiming at cross collisions among nodes widely presented at Binary Exponential Backoff（BEB） algorithm and its various improved algorithms, a Staged Collision Resolution algorithm with Linearly Varying contention window （LV-SCR） is proposed in this paper. It thoroughly eliminates cross collisions among nodes by separating the backoff slots of nodes in different backoff stages from each other, and in order to decrease the idle probability of the channel, LV-SCR algorithm also adopts a linear adjustment mechanism of contention window. The simulation results show that in the absence of significant deterioration of network throughput and average access delay of data frames, LV-SCR algorithm can reduce the times of collisions among nodes by 10 to more than 50 percent compared with BEB algorithm.

Key words: cross collisions, linearly varying contention window, staged collision resolution algorithm, times of collisions

摘要： 设计合理的冲突解析机制可有效提高无线信道利用率。针对二进制指数退避（Binary Exponential Backoff，BEB）算法及其各种改进算法中普遍存在的节点间交叉冲突问题，提出一种竞争窗口线性变化的分级冲突解析算法（Staged Collision Resolution algorithm with Linearly Varying contention window，LV-SCR）。它通过使处于不同退避阶段节点的退避时隙互相隔离，彻底消除了节点间的交叉冲突；为降低信道空闲概率，还采用了一种竞争窗口的线性调节机制。仿真结果表明，与BEB算法相比，在网络吞吐量和数据帧平均接入时延未明显恶化的情况下，LV-SCR算法可使节点间的碰撞次数减少10%至50%以上。

关键词: 交叉冲突, 竞争窗口线性变化, 分级冲突解析算法, 碰撞次数