无线Ad hoc网络传输容量的性能分析

Performance Analysis of Transmission Capacity in Wireless Ad hoc Networks

无线Ad hoc网络由于其具备自组织、自配置以及自适应等能力,被灵活地应用于各种无任何固定通信基础设施支撑的环境中。如何对网络容量性能进行评估,是目前无线Ad hoc网络研究的热点问题之一。该文依据随机几何理论以及泊松点过程建立了无线Ad hoc网络模型,基于不同的调制方式及纠错编码方案,并结合功率控制机制,分别分析了采用时隙ALOHA、非时隙ALOHA及CSMA协议时,无线Ad hoc网络的中断概率及传输容量的性能指标。数值仿真结果表明:在分组错误概率受限的条件下,对调制方式与编码方案选择与网络空间分组密度(即网络累积干扰)有关;根据不同的空间分组密度选取调制方式和编码方案,才能获取最佳的网络容量性能。

The intrinsic characteristics of wireless Ad hoc network,such as self-organizing,self-configuration and self-adaptation,make this kind of network an attractive solution in several scenarios in which lack of a fixed infrastructure.How to evaluate the capacity performance becomes one of the hop topics in the research area of wireless Ad hoc networks.In this paper,stochastic geometry and Poisson point process are applied to establish the network model under different medium access control schemes,namely un-slotted,slotted ALOHA,and CSMA.Based on different modulation/coding schemes and assuming channel inversion power control strategy,outage probability and transmission capacity of networks are investigated.The numerical results show that under a constraint of maximum packet error probability,the choices of the modulation and coding schemes that maximize the transmission capacity,depend on the density of transmissions,and that is,the interference level of the network.