Tcp Network Coding Simulation And Key Technology Study On Wireless Networks

Wireless network has features of high random bit error rate, interference and signal decline. Standard TCP will consider packet loss caused by these problems as a sign of congestion, and decrease the size of sending window, resulting in a low throughput, which can not make full use of network resources. The notion of network coding shed light upon this problem. By coding network packets and sending them with redundancy, packet loss can be covered. Throughput can be promoted and so as to the whole performance of the network.Based on the existing study, this paper study the detailed technology of network coding TCP and proved that network coding TCP can significantly improve the performance of the lossy network. Meanwhile, some unnegligible problems have also been found, say fixed redundancy parameter, asynchronism of decoding and transmission of data. This paper proposes a mechanism that combines redundancy parameter with feedback and dynamically adjusts the decoding window size of the protocol aimed at solving the problems. It designs a new mechanism for sending redundant packets, and adjusts the redundancy parameter with feedback of the receiver. It adjusts the size of the coding window according to decoding delay, and come up with a new way of sending packets and acknowledgement.The whole improved network coding TCP is implemented in Network Simulator2. Simulation results show that the new mechanism solved the problem of redundancy parameter and asynchronism of decoding and data transmission. Compared with previous network coding TCP, the improved one greatly enhances throughput and both network coding TCP has better performance than standard TCP-Vegas.