Abstract: In wireless network, channel interference and noise cause significant performance degradation of TCP. In order to solve the problems existing in the application of TCP Vegas, based on TCP New Vegas algorithm, combining the advantages of TCP Vegas A+ algorithm, an improved algorithm named TCP Vegas-P was proposed. It was improved to solve the premature end of the slow start phase and congestion avoidance in the reverse link congestion resulting in the throughput decline, and the fairness deterioration when it was accompanied by NewReno. The simulation results show that the improved algorithm in the wireless network can better estimate Round-Trip Time (RTT), and resolve the problems about Vegas, and can be well applied to wireless network environment.

Key words: wireless network, TCP Vegas, Round-Trip Time (RTT), relative delay, asymmetric network

摘要： 在无线网络环境中，TCP Vegas应用时会受到无线信道干扰和噪声的影响，对往返延时（RTT）难以进行准确的估计，导致其性能大幅度降低。结合TCP New Vegas和TCP Vegas A+等的优点提出一种改进算法TCP Vegas-P。该算法针对慢启动过早结束和拥塞避免阶段拥塞出现在反向链路上导致吞吐量下降的问题，以及在与NewReno共存时公平性恶化的问题进行了综合的改进。经仿真实验，改进的算法在无线网络中能够进行比较好的RTT估计，对解决上述Vegas存在的问题达到了良好的效果。

关键词: 无线网络, TCP Vegas, 往返延时, 相对延时, 非对称网络