Researches And Applications Of TCP Agent Acknowledgement On Broadband Wireless Communication Systems

The Transfer Control Protocol (TCP) is one of the most important protocols in Internet Protocol Family。It is applied to meeting the stability, heterogeneity, impartiality and efficiency of Internet. It provides reliable and robust end-to-end connection. TCP is initially designed for fixed networks. It is known that many applications running in the Internet such as WWW, FTP and EMAIL work with the TCP Protocol.The broadband wireless communication will be the first choice in much wireless traffic with the application of broadband technique. Many different access systems can be connected expediently, moreover core network and access network can upgrade independently based on IP network. TCP is the most widely used transfer protocol in the current Internet so that TCP's performance over wireless network is very important for future broadband wireless subscribers.In wireless network, the wireless bit error rate (BER) is high, available bandwidth is narrow, which are the main reasons causing the packet losses. TCP initially come out for wire network, and assume that all packet losses are caused by congestion. While TCP runs over wireless networks, it cannot distinguish short-lived wireless error from congestion, and then decreases its sending rate, which results in the severely degraded performance of TCP transmissions over wireless networks. The thesis firstly gives a deep understanding of the TCP mechanism, secondly presents the performances of TCP/IP protocol suiting over the Wireless Link, thirdly analyze several existing improved methods. Then a solution called TCP acknowledgement agent is put forward, which can save much up-bandwidth, more adapt future network and improve the TCP performance over wireless network depending on data-link-layer ARQ protocol. This paper discusses the mechanism, and describes the arithmetic of the solution in detail on two systems, which one is Base-Mobile system and the other is AP-CPE system. Finally the arithmetic simulation is carried out to support the improved method in this paper.The dissimilarity in these two systems is pointed out and is dissertated at length. In this paper the arithmetic simulation is carried out to support the improved method. The system that has no TCP acknowledgement agent arithmetic and the system that has are compared and analyzed. So does the last one in different conditions. The result indicates that the solution can remarkably improve the TCP performance in bad environment, and greatly raise the wireless link up-bandwidth usage, and reach an applicable level. The conclusion about this whole thesis is at the end of the paper, which includes the strongpoint and shortcoming of the solution and points out the reformative way.