摘要
IEEE 80 2 11采用异步传输方式作为媒体层的主要技术 ,而基于载波检测碰撞避免的分布式接入机制则是其最大的特点 .关于分布式接入机制的研究 ,目前已经有了许多的模型 ,但是 ,大部分的模型都是研究终端所产生的数据包是固定长度 ,很少有模型来研究终端数据包是可变长度的情况 .这种情况下的难点就是不易求得碰撞发生时信道所消耗的时间长度 .本文则研究在终端数据包长度的分布函数为f(x)下协议的吞吐量和延迟性能模型 .首先本文将原标准协议的退避算法看成是有固定大小的竞争窗口 ,用以求得站点的发送概率 ;然后 ,分析信道的工作状态 ,给出了性能模型 ,重点在求解碰撞消耗的信道时间 ,在文章的最后 ,我们通过仿真试验来验证了模型的正确性 .
The IEEE 802.11 is used to support asynchronous and time bounded delivery of radio data packets. The primary MAC technique of 802.11 is called distributed coordination Function (DCF), which is based on Carrier Sense Multiple Access with Collision Avoidance (CSMA/CA) mechanism with binary slotted exponential backoff. The basic access and the RTS/CTS access mechanisms are the packet transmission schemes employed by DCF. There have been few models to analysis the combination of the basic and RTS/CTS scheme until now. In this paper, we propose an analytical model to evaluate the throughput and delay performance of a combination mechanism, in the assumption that the distribution function of the packet length is a general function f(x). The accuracy of our model is validated by elaborate simulations.
出处
《电子学报》
EI
CAS
CSCD
北大核心
2005年第1期138-141,共4页
Acta Electronica Sinica
关键词
无线局域网
性能评估
性能模型
碰撞检测碰撞避免
分布式协调机制
Carrier sense multiple access
Collision avoidance
Computer simulation
Mathematical models
Probability
Radio communication
Wireless telecommunication systems
