多径衰落信道下TCP协议的分析及改进

Analyzing and Improving of TCP under Multipath Fading Channel

为了区分大尺度传播模型和多径衰落的小尺度模型在实际传播环境下的不同,针对无线信道多径衰落的特点,分析了TCP(Transmission Control Protocol)在多径衰落信道下的特性,提出了一种根据当前网络实际情况进行带宽估计而采取相应拥塞控制机制的TCP协议,并对不同TCP版本和改进后的协议进行了仿真分析。结果表明,改进后的协议能够根据网络的状况进行有效的拥塞控制,在既存有网络拥塞又有多径衰落导致丢包的情况下,其算法的吞吐率比TCP-Sack提高了约17.8%。

In order to differentiate the small-scale propagation model and large-scale propagation model, this paper discusses the characteristics of the wireless channel and analysises the throughput of TCP （Transmission Control Protocol） under multipath fading channel. According to the current of estimation network bandwidth an updated TCP Congestion Control Mechanism protocol is explored. The different TCP versions of the protocol and the updated TCP protocol were simulated. The results show that the updated TCP protocol can take the congestion control mechanism more effectively. When there are network congestion and the multipath fading, 17.8% throughput in the improved algorithm is improved than TCP-Sack.