Optimization of TCP Over Wireless Networks

Abstract — As mobile devices are popular portals for internet users; they have some basic design limitations of the TCP having congestion control mechanism. But in mobile wireless networks, non congestion related packet losses due to varying signal power inherent with mobility and handover between base-stations are dominant. Due to the misinterpretation of such non congestion related packet losses optimum performance is compromised. This paper provides an overview of the challenges and suggests optimization techniques for TCP in wireless network environments. The consequence is a wireless enhancement scheme for TCP called Congestion Coherence. By several investigations and statistical analysis, we identified that the performance degradation of wireless TCP is mainly due to the timeout resulting from frequent packet losses. This scheme determines the cause of packet loss by using the sequential coherence of packet marking, it uses three-level ECN signals to detect congestion loss and to reduce number of timeouts established on the perception that congestion neither happens nor disappears abruptly. Simulations show that the performance and efficiency of this technique is better than the existing techniques. Index Term-- ECN, TCP, ECN-Echo I