TCP Performance Analysis And Research In MANET

The characteristics that distinguish wireless Ad Hoc Network from wired and other wireless networks are infrastructure-less,multi-hop,self-organized and dynamic topologies,which lead to the TCP implementations with poor performance in the MANET.Traditional TCP is the transmission control mechanism that designed for a cable network,which is a great success over the Internet.However, because of the protocol ascribes the reasons of data segment lost to the network congestion,and it ignores the factors that may affect the TCP performance such as changes in routing,high bit error rate and channel conflict.Thereby the traditional TCP in MANET can not achieve the desired results.With the continuous development of mobile technology,the research of TCP in MANET has become a hot.TCP congestion control and ACK mechanism are thoroughly discussed and thus improved in this dissertation.First,as the impact of congestion control that comes from the frequently routing changes,the RC-Vegas program based on TCP Vegas is designed in the dissertation.The program can identify the RTT change that. caused by the route changed,andthen updates the BaseRTT timely,so as to avoid in response to congestion avoidance control for mistake.In addition,the MAD-ACK program is designed to ease the channel competition conflict from the perspective of transport layer.To reduce the competitiveness of the wireless channel by reasonable reducing the number of ACK is the core idea.Finally,the improved solutions were simulated under the platform of NS2.Analysis results show that the improved solutions can significantly improve network performance, such as network throughput et al.