Enhanced Backpressure Routing Using Wireless Link Features

TL;DR

This paper improves backpressure routing in wireless networks by using wireless link features to optimize bias scaling, maintain biases under mobility, and incorporate sojourn time awareness, significantly reducing delay and enhancing performance.

Contribution

It introduces a novel bias scaling method using link features, a low-overhead bias maintenance scheme for mobility, and a bio-inspired sojourn time metric for better last packet handling.

Findings

Proper bias scaling reduces end-to-end delay.

Bias maintenance scheme is effective under mobility.

Sojourn time-aware metric outperforms existing methods.

Abstract

Backpressure (BP) routing is a well-established framework for distributed routing and scheduling in wireless multi-hop networks. However, the basic BP scheme suffers from poor end-to-end delay due to the drawbacks of slow startup, random walk, and the last packet problem. Biased BP with shortest path awareness can address the first two drawbacks, and sojourn time-based backlog metrics were proposed for the last packet problem. Furthermore, these BP variations require no additional signaling overhead in each time step compared to the basic BP. In this work, we further address three long-standing challenges associated with the aforementioned low-cost BP variations, including optimal scaling of the biases, bias maintenance under mobility, and incorporating sojourn time awareness into biased BP. Our analysis and experimental results show that proper scaling of biases can be achieved with the help of common link features, which can effectively reduce end-to-end delay of BP by mitigating the random walk of packets under low-to-medium traffic, including the last packet scenario. In addition, our low-overhead bias maintenance scheme is shown to be effective under mobility, and our bio-inspired sojourn time-aware backlog metric is demonstrated to be more efficient and effective for the last packet problem than existing approaches when incorporated into biased BP.