Wireless Congestion Control Protocol For Multihop Ad Hoc Networks

TL;DR

This paper introduces WCCP, a new congestion control protocol for multihop ad hoc networks that improves fairness, efficiency, and reduces delay by using a novel channel busyness ratio metric.

Contribution

The paper proposes WCCP, a congestion control protocol that uses channel busyness ratio for better network utilization and fairness in multihop ad hoc networks.

Findings

WCCP outperforms traditional TCP in channel utilization.

WCCP reduces delay and improves fairness.

WCCP eliminates starvation problems.

Abstract

The traditional TCP congestion control mechanism encounters a number of new problems and suffers a poor performance when the IEEE 802.11 MAC protocol is used in multihop ad hoc networks. Many of the problems result from medium contention at the MAC layer. In this paper, I first illustrate that severe medium contention and congestion are intimately coupled, and TCP s congestion control algorithm becomes too coarse in its granularity, causing throughput instability and excessively long delay. Further, we illustrate TCP s severe unfairness problem due to the medium contention and the tradeoff between aggregate throughput and fairness. Then, based on the novel use of channel busyness ratio, a more accurate metric to characterize the network utilization and congestion status, I propose a new wireless congestion control protocol (WCCP) to efficiently and fairly support the transport service in multihop ad hoc networks. In this protocol, each forwarding node along a traffic flow exercises the internode and intranode fair resource allocation and determines the MAC layer feedback accordingly. The endtoend feedback, which is ultimately determined by the bottleneck node along the flow, is carried back to the source to control its sending rate. Extensive simulations show that WCCP significantly outperforms traditional TCP in terms of channel utilization, delay, and fairness, and eliminates the starvation problem.