TCP Kay: An end-to-end improvement to TCP performance in lossy wireless networks using ACK-DIV technique & FEC

Abstract

Wireless networks have evolved considerably in the last decade and the world has seen an exponential increase in the number of mobile device users. The performance of the wireless networks has become a critical factor and researchers nowadays are trying to bring out even the slightest increase in network performance wherever possible. TCP, which is the most dominant transport protocol of the Internet, fails to perform well in lossy wireless networks because it cannot differentiate congestion losses from non-congestion losses. This paper aims to improve the performance of TCP in lossy wireless networks and the resulting protocol is termed as TCP Kay. The major contributions of TCP Kay are: (1) it uses a modified ACK-DIV (Acknowledgment Division) technique for combating the loss of acknowledgement packets (ACKs) on the reverse path and (2) it combines the modified ACK-DIV technique with FEC to further enhance the robustness of data transmission in lossy wireless networks. The performance of TCP Kay has been studied using ns-2 and the same has been compared with TCP Reno with SACK (TCP SACK) and TCP Westwood+ (TCPW+). Results show that TCP Kay outperforms other TCPs in terms of goodput, received/sent ratio and packet drop rate in various wireless scenarios with up to 5% packet error rate.