A Near-Optimal Scheme for TCP ACK Pacing to Maintain Throughput in Wireless Networks

TL;DR

This paper introduces a near-optimal ACK pacing scheme at the base station to improve TCP throughput in wireless networks by predicting link outages and pacing acknowledgments accordingly.

Contribution

It presents a novel cross-layer ACK pacing scheme that predicts link failures and adjusts ACK timing to maintain TCP throughput in wireless environments.

Findings

Significant throughput improvement observed with the ACK pacing scheme

Effective prediction of link outages enhances TCP performance

The scheme is practical and easily implementable in existing systems

Abstract

The advent of fourth generation technologies in wireless networks and the rapid growth of 3G have heralded an era that will require researchers to find reliable and easily implement-able solutions to the problem of poor TCP performance in the wireless environment. Since a large part of the Internet is TCP-based, solving this problem will be instrumental in determining if the move from wired to wireless will be seamless or not. This paper proposes a scheme that uses the base station's ability to predict the time at which the link may be going down and to estimate the period for which the mobile would be unreachable due to conditions like fading. By using cross-layer and ACK pacing algorithms, the base station prevents the fixed host from timing out while waiting for ACKs from the mobile. This in turn prevents TCP on the fixed host from bringing down the throughput drastically due to temporary network conditions, caused by mobility or the unreliability of wireless links. Experimental results indicate a reasonable increase in throughput when the ACK holding scheme is used.