Probing-based anypath forwarding routing algorithms in wireless mesh networks

Abstract

Existing routing protocols for Wireless Mesh Networks (WMNs) are generally optimized with statistical link measures, without focusing on the intrinsic uncertainty of wireless links. We show evidence that, with the transient link uncertainties at PHY and MAC layers, a pseudo-deterministic routing protocol that relies on average or historic statistics can hardly explore the full potentials of a multi-hop wireless mesh.We study optimal WMN routing using probing-based anypath forwarding, with explicit consideration of transient link uncertainties. Starting from a two-state link capacity model, we show the underlying connection between WMN routing and the classic Canadian Traveller Problem (CTP) [1]. Inspired by a stochastic recoverable version of CTP (SRCTP), we develop an practical SRCTP-based online routing algorithm under link uncertainties. We study how dynamic next-hop selection can be done with low cost, and derive a systematic selection order for minimizing transmission delay. We further extend our solution to a general multi-rate link model, and present a Stopping Theory (ST) based solution, which naturally degrades to the SRCTP algorithm in the two-state link model. We conduct simulation studies to verify the effectiveness of the SRCTP and ST algorithms under diverse network configurations. In particular, compared to deterministic routing, reduction of end-to-end delay (51.15–73.02% for two-state links, 5.16% for multi-rate links) and improvement on packet delivery ratio (99.76% for two-state links, 94.44% for multi-rate links) are observed. By using RTS/CTS as the online probing tool in ns3 simulator, we observed both significant goodput improvements (29.9% than EXOR, 61.8% than HWMP) and much less packet arriving jitter (14.27 times less than EXOR, 45% less than HWMP) as compared to EXOR and HWMP routing protocols.