随着网络通信技术的迅猛发展，人们可以通过互联网方便快捷地获得各种服务。而在人们对各种服务的需求呈指数上升的时候，地面互联网的带宽等瓶颈问题己急待解决。而卫星网络通信具有广域覆盖、高传输速率的优势，使得基于卫星的互联网技术必将成为今后通信领域的研究热点。由于卫星信道的特点有别于地面信道，如长时延，高误码率等，使得适用于地面网络的TCP协议不能很好的为卫星网络服务，因此必须针对卫星信道的特点对TCP协议予以改进。 本文首先介绍了拥塞控制的基本概念及传统TCP拥塞控制算法，分析了现有的针对卫星网络中的TCP性能的改进方案，首先对现有针对卫星网络拥塞控制方案进行了整体的分析，论述了基于端到端的改进方案、链路层设计方案和TCP分裂链接方案。论文以端到端的改进协议为依据，进行了研究和改进，主要针对两个方面进行了研究：一方面针对TCP-Peach+算法在高误码率环境中零元数据段丢失严重，导致在急速恢复阶段使得拥塞窗口很难恢复到初始状态，拥塞窗口逐渐降低进而导致数据传输速率不断降低的问题，提出了一种急速恢复的改进机制，来抑制拥塞窗口的逐渐降低和TCP-Peach+性能的恶化。另一方面针对TCP-Peach+算法在拥塞避免阶段仍然是传统的将慢启动阀值设为cwnd/2的机制，对现有带宽资源是一种浪费的问题，提出了一种新的基于带宽估计的TCP-nPeach算法，该算法通过观察确认信号到达的情况进行准确的带宽估计，在收到3个重复确认信号时根据估计带宽设置拥塞窗口和慢启动阀值。 本文最后采用网络仿真工具NS2构建了卫星信道仿真模型，对TCP-Peach、TCP-Peach+及其改进方案进行了性能仿真。结果证明，新算法在吞吐量和公平性方面都有很好的改进。

With the rapid development of network technology, people can through the Internet convenient access to a variety of services. In people's demand for various services rising exponentially,the ground of Internet bandwidth bottleneck problem has to be solved. But the satellite communication network with wide coverage, high transmission speed advantage, so the satellite-based Internet will become the research focus in communication field. Due to the characteristics of satellite channel is different from the ground channel, such as long delay, high bit error rate, which is suitable for the ground network TCP protocol can not be very good for the satellite network service, so we must according to the characteristics of satellite channel make improvement on TCP protocol. This paper first introduces the basic concepts of congestion control and traditional TCP congestion control algorithm, analyzes the improvement scheme for TCP performance in satellite networks existing. Firstly, according to the satellite network congestion control scheme of the overall analysis, discusses the improvement scheme, based on end to end link layer design scheme and split link schemes, and proposed the research focuses. The end to end on the basis of the improved protocol, are studied and improved, mainly in two aspects: on the one hand, according to the study of TCP-Peach+ algorithm in high BER environments zero metadata section loss serious, resulting in the rapid recovery phase so that the congestion window is very difficult to restore to the original state, the congestion window reduced gradually and the in the data transmission rate continued to reduce the problems, propose an improved mechanism of rapid recovery, to inhibit the deterioration of the congestion window reduced gradually and the performance of TCP-Peach+. On the other hand, in view of the TCP-Peach+ algorithm in congestion avoidance phase is still the traditional will slow start threshold set to the cwnd/2 mechanism, which is a waste of bandwidth resources of existing problems, a new TCP-nPeach algorithm based on bandwidth estimation algorithm was proposed, which was confirmed by the observation signal arrival of accurate estimation of bandwidth, after receiving 3 duplicate ACK according to the estimated bandwidth congestion window and slow start threshold. This paper finally build a satellite channel simulation model using network simulation tool NS2, TCP-Peach, TCP-Peach+ and the improved scheme for performance simulation. Results show that, the new algorithm has a very good improvement in terms of throughput and fairness.