基于指示信息的带碰撞避免的载波侦听多址技术

摘要

本文从现有协议中DCF机制的基本和RTS/CTS两种工作模式出发,提出一种基于指示信息的带碰撞避免的载波侦听多址技术,根据不同工作模式分为三种改进模式.针对两种对数据帧长适应性较好的改进工作模式,即改进的基本模式和改进的RTS/CTS模式一,本文提出在整个网络数据传输速率固定的条件下,可设定数据帧长阈值,根据传输数据帧长与阈值关系实现两种改进模式的动态切换,最大化地缩短碰撞处理时间,降低随机回退产生的额外系统开销.NS2仿真结果表明,基于指示信息的带碰撞避免的载波侦听多址技术相比于现有的DCF机制具有更好的系统性能.%According to both the basic mode and RTS/CTS mode of DCF in existing standards,a novel mechanism of Carrier Sense Multiple Access with Collision Avoidance based on the indication information is proposed,which is divided into three improved modes.The improved basic mode and the improved RTS/CTS mode 1 with better adaptability to the length of data frame are put forward as two improved modes and it's suggested that the threshold of the data frame length could be set under the condition of fixed transmission rate of data in the network.Then according to the relationship between the length of data frame and the threshold,dynamic switch between two improved modes could be implemented.As a result,the processing time of collision will be shortened and additional system overhead caused by random back-off will be reduced.The simulation results of NS2 show that Carrier Sense Multiple Access with Collision Avoidance based on the indication information has better system performance compared with the conventional DCF mechanism.