Joint Link Rate Selection and Channel State Change Detection in Block-Fading Channels

TL;DR

This paper develops a joint channel change detection and rate selection algorithm for block-fading wireless links, improving adaptivity and reducing regret in dynamic environments.

Contribution

It introduces a novel CD-TS algorithm that combines change-point detection with Thompson Sampling for rate selection in block-fading channels.

Findings

Achieves sublinear regret when channel coherence time exceeds a threshold.

Improved algorithm accounts for higher packet-loss at increased transmission rates.

Validated through numerical simulations demonstrating effectiveness.

Abstract

In this work, we consider the problem of transmission rate selection for a discrete time point-to-point block fading wireless communication link. The wireless channel remains constant within the channel coherence time but can change rapidly across blocks. The goal is to design a link rate selection strategy that can identify the best transmission rate quickly and adaptively in quasi-static channels. This problem can be cast into the stochastic bandit framework, and the unawareness of time-stamps where channel changes necessitates running change-point detection simultaneously with stochastic bandit algorithms to improve adaptivity. We present a joint channel change-point detection and link rate selection algorithm based on Thompson Sampling (CD-TS) and show it can achieve a sublinear regret with respect to the number of time steps $T$ when the channel coherence time is larger than a threshold. We then improve the CD-TS algorithm by considering the fact that higher transmission rate has higher packet-loss probability. Finally, we validate the performance of the proposed algorithms through numerical simulations.