Research On Performance Improvement Of Wireless Networks

With the development of computer network and technology, wireless network plays an important role , which also has great influence on the performance of TCP connections. TCP is designed for wired network, and considers all packet losses due to congestion, this then trigger's congestion control which decreases the sender's congestion window. Compared with wired network environment, in wireless network, the communication has a problem which is high bit error rate, thus the data packet that has been sent to the receiver may be discarded by some bits error in the packet. Hence, the transport layer protocols like TCP could not make a distinction between wireless losses and congestion losses. Meanwhile the congestion window is always reduced due to the high bit error, as the packet sending rate is reduced. Therefore, resulting to bad performance of network and the waste of network resource.Scheme to improve TCP performance in wireless networks had been made, it includes end-to-end scheme, data link layer scheme, split connection scheme and cross layer scheme. These schemes can effectively improve the TCP performance under wireless networks, but they also have some problem. We need to do more research on them to make TCP protocol can be better using in wireless networks.In this paper, we first summarize what are the difficulties and challenges that TCP protocol has to face in wireless environment. Then analyzed the development and review current researches on the wireless network area. In order to meet the TCP protocol in wireless networks, we propose amendments to TCP protocol.The scheme is modified to improve transmission performance in wireless network and amend the Snoop protocol. I studied the simulation tool NS-2. Through analyzing the data gotten from the simulation, it can be seen that amended protocol is adaptive to wireless network, can work well in high bit error rate.