Reducing Congestion Effects in Wireless Networks by Multipath Routing

Abstract

We propose a solution to improve fairness and increase throughput in wireless networks with location information. Our approach consists of a multipath routing protocol, biased geographical routing (BGR), and two congestion control algorithms, in-network packet scatter (IPS) and end-to-end packet scatter (EPS), which leverage BGR to avoid the congested areas of the network. BGR achieves good performance while incurring a communication overhead of just 1 byte per data packet, and has a computational complexity similar to greedy geographic routing. IPS alleviates transient congestion by splitting traffic immediately before the congested areas. In contrast, EPS alleviates long term congestion by splitting the flow at the source, and performing rate control. EPS selects the paths dynamically, and uses a less aggressive congestion control mechanism on non-greedy paths to improve energy efficiency. Simulation and experimental results show that our solution achieves its objectives. Extensive ns-2 simulations show that our solution improves both fairness and throughput as compared to single path greedy routing. Our solution reduces the variance of throughput across all flows by 35%, reduction which is mainly achieved by increasing throughput of long-range flows with around 70%. Furthermore, overall network throughput increases by approximately 10% Experimental results on a 50- node testbed are consistent with our simulation results, suggesting that BGR is effective in practice.