车载自组织网络中基于邻居节点数估计的最小竞争窗口调整算法

摘要

In order to solve the periodic broadcast scalability of IEEE 802.11p-based VANET on control channel,a minimum contention window adjustment algorithm based on neighbor nodes number estimation was proposed.First of all,in order to minimize the collision probability,the relationship between minimum contention window (CWmin) and active node number n was deduced on the basis of Markov model IEEE 802.11 broadcast backoff.Then minimum contention window was adjusted dynamically by estimating the number of neighbor nodes in real time.Finally,the proposed algorithm and the original's fixed CWmin method were compared by simulation,and the results show that the proposed algorithm is superior to the original method in broadcast reception rate.%针对基于IEEE 802.11p的车载自组织网络(VANET)中控制信道上周期性广播的可扩展性问题,提出了一种基于邻居节点估计的最小竞争窗口调整算法.首先,在IEEE 802.11广播退避的马尔可夫模型的基础上,以最小化碰撞概率为目的,推导出最小竞争窗口(CWmin)和活跃节点数n之间的关系；然后,利用周期性广播的beacon消息的特点对节点的邻居节点数进行实时估计,并根据估计的邻居节点数动态调整最小竞争窗口；最后,对提出的算法和IEEE 802.11p固定CWmin方法进行仿真比较分析.结果表明,提出的算法在广播接收率上优于原始方法.