多跳无线网络中路径端到端容量的准确计算

Accurate Calculation of End-to-End Throughput Capacity for Wireless Multi-Hop Networks

多跳无线网络中路径的端到端容量,是指业务在该路径上的端到端吞吐量所能达到的最大值.获取该信息有非常重要的意义,同时也是很有挑战性的工作.目前,已有的工作在计算端到端容量时,要么假设路径上各跳链路间获得了完美的同步,无线资源在竞争链路间平均分配,这种方法忽略了多跳路径中由隐藏节点引起的碰撞,获得的结果与实际测试结果有较大的差异;要么通过复杂的非线性方程组的求解来计算端到端容量,在较大规模的无线网络中,这种方法的实用性又受到限制.首先,完成对基于IEEE 802.11的多跳无线路径中由隐藏节点引起碰撞概率的准确数学表达;然后,利用最优化问题来分析多跳路径中各跳链路间的竞争问题,进而建立了准确、简便的端到端容量计算方法.而且,该方法还考虑了无线网络中多速率传输的情况.仿真结果表明,该方法显著提高了端到端容量计算结果的准确度,并且复杂度低、易于实现,具有很好的应用前景.

To determine the end-to-end throughput capacity of IEEE 802.11-based wireless networks, existing works used a simplistic approach to divide the 1-hop throughput capacity by the number of contending links in the bottleneck region, which has is limited in terms accuracy, and relies on complicated non-linear equations. This makes it impractical to solve for a large number of hops. This paper presents an optimization methodology to analytically calculate the end-to-end throughput capacity of IEEE 802.11-based chain-topology wireless networks. The calculation considers the interference due to neighboring nodes and assesses the impact of hidden node collision as well as multi-rate terminals （i.e., nodes can transmit at different rates） on throughput capacity. The proposed methodology provides a very accurate calculation of the end-to-end throughput capacity when compared to existing works, and yet, is more practical to implement. With extensive simulation experiments, the study verifies the analysis and validates the proposed methodology.