This thesis deals with the investigation of transmission control protocol (TCP) performance in non-wire line (Cellular Mobile System) environments. TCP Congestion Control analysis has been analyzed in Java Programming Language. The congestion control has been simulated in Java programming language environment and it also investigates of the effects of combining forward error correction (FEC) with TCP in simulation environment of Java. FEC reduces the number of retransmissions and shows better congestion control behavior, which can effectively run the network at a higher load. In TCP/IP Protocol Architecture, TCP provides reliable end-to-end communication. Traditional TCP implementations are tuned to work well over wired networks. A packet loss is occurred in a wired network mainly due to network congestion. On the other hand in a wireless link packet losses are caused mainly due to bit errors resulted from noise, interference, and various kind of fading. TCP has no idea whether a packet loss is caused by congestion or bit error. TCP assumes loss is caused by congestion and turns on its congestion control algorithms to slow down the amount of data it transmits. So invoking congestion control algorithm for bit errors of wireless channel reduces TCP throughput drastically. Proposal of this thesis is to analysis congestion/packet loss. FEC means adding some redundancy information along with data that means this redundancy will consume some portion of the available bandwidth. But using FEC reduces the number of retransmission at TCP level and thus preserves time to send more data. As a result overall performance may be increased. By simulation in Java Programming Language and in Windows Environment the comparison between various TCP versions is done and it is demonstrated that in certain cases performance of accurate data transmission can be increased significantly.
Keywords: TCP/IP, Cellular Mobile System, forward error correction, throughput, congestion/packet loss. Wireless-link-packet, Java Programming, Eclipse Framework, Simulation, Add-hoc network.