Analysis And Improvement Of TCP Performance Of Ad Hoc Networks

This paper introduces the Ad hoc wireless communication networks, as well as its scope of application and the status of study . Qn the basis of understanding Congestion Control protocol, it point out the problem: Traditional TCP protocol 's design was just concerning about wire network .It Contributes the loss of data package to network congestion and employ congestion—control process to solve the problem .The traditional TCP protocol is not Appropriate for the speciality of Ad hoc network environment .As the loss of data Package in Ad hoc network may be resulted from node movement, error of wireless Channel or something else .Traditional TCP protocol can not correctly find the Reason for Package loss and just conduct congestion—control, leading to the decrease of TCP performance .So it is crucial to improve traditional TCP to make it fit into Ad hoc network.In this paper, the author have analyzed the effect on TCP performance caused by Ad hoc network And the existing scheme has been classified and summarized from two aspects of datalink layer and network layer, which pointed out that the effect on TCP performance induced by datalink layer was mainly caused by hidden terminal and exposed terminal. And then the author divided in two improved schemes: network-oriented and end-to-end network and adressed the comparison among schemes.According to the problem of datalink layer, adding properly the minium congestion window could effectively improve data throughput, hidden terminal and exposed terminal so as to improve the instability of TCP, which was testified effectively though the simulation results. According to the existing scheme, the author have proposed a new end-to-end scheme, though which the receiver could speculate network situation according to the value of propagation delay and explicitly notify the sender whether it will has a congestion or not depending on the returned ACK. So the advantage of the scheme is not to introduce excess computing cost on the receiver. It showed it effective via the simulation results.