To Stay Or To Switch: Multiuser Dynamic Channel Access

TL;DR

This paper investigates multiuser dynamic channel access in cognitive radio networks, focusing on how multiple users can optimally switch channels considering finite data arrivals and system congestion, to improve spectrum utilization.

Contribution

It introduces a novel analysis of collective multiuser channel switching with finite arrivals, extending prior work on spectral and temporal diversity exploitation.

Findings

Congestion significantly impacts opportunistic switching gains.

Optimal policies depend on user arrival patterns and system load.

System performance improves with coordinated multiuser strategies.

Abstract

In this paper we study opportunistic spectrum access (OSA) policies in a multiuser multichannel random access cognitive radio network, where users perform channel probing and switching in order to obtain better channel condition or higher instantaneous transmission quality. However, unlikely many prior works in this area, including those on channel probing and switching policies for a single user to exploit spectral diversity, and on probing and access policies for multiple users over a single channel to exploit temporal and multiuser diversity, in this study we consider the collective switching of multiple users over multiple channels. In addition, we consider finite arrivals, i.e., users are not assumed to always have data to send and demand for channel follow a certain arrival process. Under such a scenario, the users' ability to opportunistically exploit temporal diversity (the temporal variation in channel quality over a single channel) and spectral diversity (quality variation across multiple channels at a given time) is greatly affected by the level of congestion in the system. We investigate the optimal decision process in this case, and evaluate the extent to which congestion affects potential gains from opportunistic dynamic channel switching.