Improving TCP Performance over Wireless Network with Frequent Disconnections

TL;DR

This paper proposes a new scheme with cross-layer modifications to improve TCP performance over wireless links with frequent disconnections, reducing timeouts and decoupling congestion control from link failure recovery, demonstrated through extensive simulations.

Contribution

It introduces a novel cross-layer approach that modifies TCP and link layer interactions to enhance performance during frequent wireless disconnections.

Findings

Significant reduction in TCP timeout occurrences.

Improved throughput and reduced latency during link failures.

Enhanced robustness of TCP over unreliable wireless links.

Abstract

Presented in this paper is the solution to the problem that arises when the TCP/IP protocol suite is used to provide Internet connectivity through mobile terminals over emerging 802.11 wireless links. Taking into consideration the strong drive towards wireless Internet access through mobile terminals, the problem of frequent disconnections causing serial timeouts is examined and analyzed, with the help of extensive simulations. After a detailed review of wireless link loss recovery mechanism and identification of related problems, a new scheme with modifications at link layer and transport layer is proposed. The proposed modifications which depend on interaction between two layers (i) reduce the idle time before transmission at TCP by preventing timeout occurrences and (ii) decouple the congestion control from recovery of the losses due to link failure. Results of simulation based experiments demonstrate considerable performance improvement with the proposed modifications over the conventional TCP, when a wireless sender is experiencing frequent link failures.