Opportunistic Scheduling in Underlay Cognitive Radio based Systems: User Selection Probability Analysis

TL;DR

This paper derives closed-form expressions for user selection probabilities in an underlay cognitive radio system with opportunistic scheduling, highlighting fairness conditions and validating results through simulations.

Contribution

It introduces novel analytical formulas for user selection probabilities in underlay cognitive radio systems with opportunistic scheduling.

Findings

Fairness in user transmission chances depends on equal distance ratios.

Analytical results are validated by Monte Carlo simulations.

Fairness is limited to scenarios with identical distance ratios.

Abstract

In this paper, an underlay cognitive radio (CR) system is considered with multiple cognitive or secondary users contending to transmit their information to the cognitive destination (e.g., eNodeB) using the spectral resource of a primary user. The novel closed-form expressions are derived for the selection probabilities of cognitive users with opportunistic scheduling wherein an optimal metric is employed for opportunistic transmission. The analytical results corroborated by the Monte Carlo simulations, can be used to demonstrate the fairness achieved in opportunistic scheduling. It is shown that the fairness in terms of equal chance for transmission amongst all cognitive users can only be seen for the scenarios when the fraction of distances between the cognitive transmitter and cognitive receiver, and cognitive transmitter and primary receiver is identical for each of the cognitive transmitters.