Implementation and End-to-end Throughput Evaluation of an IEEE 802.11 Compliant Version of the Enhanced-Backpressure Algorithm

Extensive work has been done in wireless multihop routing with several ideas based on shortest path or load balancing routing algorithms, that aim at minimizing end-to-end delay or maximizing throughput respectively. Backpressure is a throughput-optimal scheme for multihop routing and scheduling, while Enhanced-Backpressure is an incremental work that reduces end-to-end delay without sacrificing throughput optimality. However, the implementation of both theoretical schemes is not straightforward in the presence of 802.11 MAC, mainly because of their requirement for centralized scheduling decisions that is not aligned with the aspects of CSMA/CA.

This paper proposes a novel scheme, named Enhanced-Backpressure over WiFi (EBoW), which is compatible with the decentralized operation of WiFi networks and efficiently utilizes the benefits of Enhanced- Backpressure design, combining throughput optimality with low end-to-end delay. EBoW router is implemented relying on Click framework for routing configuration. The performance of EBoW is evaluated both on a medium-scale outdoors wireless testbed as well as through experimentations in NS-3 simulator tool. The protocol has been compared against other state of the art routing protocols and we argue that EBoW is much more throughput efficient than the others, while succeeding similar end-to-end delay.