Modified Transport Control Protocol for Cellular Network

Day by day popularity of wireless devices used to access the Internet is increasing. It indicates that in the near future TCP protocol will be frequently used over the wireless links. The wireless links characteristics are significantly different from characteristics of wired links. TCP (Transport Control Protocol) is basically designed for wired network. One of the main reasons for TCP´s degraded performance in wireless networks is TCP´s interpretation that packet loss is caused by congestion. However, in wireless cellular networks packet loss occurs mostly due to high bit error rate, packet corruption, or link failure. As TCP is designed to use over wired network it needs to change when it is used over wireless network. Hence, various mechanisms were proposed to improve TCP performance over wireless links. TCP performance in wired/wireless networks may be substantially improved by modifying some of the algorithms used in TCP. This paper proposes a new TCP protocol named Modified-TCP (MTCP) that uses modified congestion algorithm, fast and local retransmission and SACK (selective acknowledgment). This makes the proposed protocol better suited in a wide range of applications in mixed wired and wireless links. This paper shows the results after comparing performance of MTCP with TCP over wired cum wireless network using network simulator ns-2.