基于RTT的TCPW拥塞控制算法的改进

无线网络受传输介质的限制,传输过程中会受到较大干扰,产生抖动,这种抖动会产生零星丢失而被拥塞控制机制误认为拥塞发生.TCP Westwood 协议(简称TCPW)就是这样不能区分拥塞丢失和无线抖动丢失,导致拥塞机制过于敏感,降低了带宽利用率.基于此,根据RTT值的估计对TCPW协议进行修改--称之为TCPW BR.该算法以测得的平滑RTT值并依据加权平均思想划分拥塞等级,判断拥塞丢失和无线抖动丢失.仿真结果表明,TCPW BR算法增强了无线网络对拥塞和随机差错的判断处理能力,提高了带宽利用率和吞吐量,并保持良好的公平性与友好性.

Enhanced TCPW congestion control scheme based RTT

Wireless network is limited by the transmission medium, transmission process would be subject to strong interference, resulting in jitter. This jitter would have sporadic loss congestion control mechanism had been mistaken for congestion. TCP westwood algorithm (TCPW) doesn' t distinguish between congestion loss and wireless loss, leading to congestion mechanism is too sensitived and bandwidth utilization is reduced. Based on the value of the RTT, a new TCP scheme is proposed, called TCPW BR, which is a revision of TCP westwood. The algorithm to smooth the measured RTT values and based on a weighted average of the ideological division of congestion levels, determine the congestion loss and wireless loss jitter. Simulation results show that, TCPW BR algorithm improves the judge handling capacity of congestion and random error on the wireless network, increases bandwidth utilization and throughput, and maintains friendliness and fairness.