Delay Sensitive Communications over Cognitive Radio Networks

TL;DR

This paper addresses delay-sensitive communication support in cognitive radio networks by formulating an optimal control problem, proposing heuristic policies, and demonstrating near-optimal performance with low complexity.

Contribution

It introduces a novel Markov decision process formulation and heuristic policies for admission control and channel allocation in cognitive radio networks.

Findings

Heuristic policies achieve near-optimal performance.

Largest-delay-first scheme is proven optimal.

Policies perform close to the theoretical upper-bound.

Abstract

Supporting the quality of service of unlicensed users in cognitive radio networks is very challenging, mainly due to dynamic resource availability because of the licensed users' activities. In this paper, we study the optimal admission control and channel allocation decisions in cognitive overlay networks in order to support delay sensitive communications of unlicensed users. We formulate it as a Markov decision process problem, and solve it by transforming the original formulation into a stochastic shortest path problem. We then propose a simple heuristic control policy, which includes a threshold-based admission control scheme and and a largest-delay-first channel allocation scheme, and prove the optimality of the largest-delay-first channel allocation scheme. We further propose an improved policy using the rollout algorithm. By comparing the performance of both proposed policies with the upper-bound of the maximum revenue, we show that our policies achieve close-to-optimal performance with low complexities.