Abstract: TCP is a transport protocol formally designed for the wired network and it is known to suffer from performance degradation in mobile wireless environment.In this paper，the authors propose modifications to the congestion avoidance mechanism of the TCP Vegas to overcome these limitations.The solution is depended on average and variance of round trip time，TCP data sender may utilize different congestion avoidance algorithms to optimize congestion window size，aims is to improve ad hoc network throughput.Simulation results show the algorithm is able to overcome several of the identified problems-it can obtain more throughput than TCP Reno and TCP Vegas.

摘要： TCP协议是针对固定可靠网络设计的一种传输协议，它把数据包丢失或延迟的原因都归结为网络拥塞。在移动自组网上直接应用TCP 协议，网络性能会因比特出错率高等原因大幅下降。针对无线自组织网络高误码的基本特征，基于TCP Vegas协议和环回时间的均值和方差改变趋势，采用不同的控制策略调节发送端的数据发送速率，从而优化传输控制协议的吞吐量，提高网络资源的利用率。仿真研究结果表明，与传统的传输控制协议相比，该算法具有更高的吞吐量和稳定的拥塞控制窗口。