Improving TCP Performance over Networks with Wireless Links

Abstract

TCP is now a widely used Internet protocol in the most of networks. All systems which want to communicate with other computers in the Internet must follow the rules of TCP. It is a reliable transport layer protocol, responsible for the end-to-end performance in the network, and it performs well in traditional networks made up of links with low bit-error rates. But when networks contain high bit-error rate links such as wireless links, TCP will degrade end-to-end performance caused by packet error in wireless link. At this time, TCP can not distinguish weather the packet loss is caused by congestion or the data error in wireless links. TCP is impractical in networks that contain wired and wireless links, and especially wireless links are part of backbone networks. We will present a novel scheme in base stations to achieve good performance without modifying the existing TCP protocol. This new scheme is quite simple in which we only add some local acknowledgments and a checksum module to guarantee the correction of packets in wireless links. The simulation results show that our scheme has better performance than the pure TCP. Especially, in high bit-error rate, our scheme provides very good performance.