Transmit Antenna Selection in Underlay Cognitive Radio Environment

TL;DR

This paper proposes a transmit antenna selection scheme for underlay cognitive radio systems that maintains interference below a threshold, deriving key performance metrics and validating results through simulations.

Contribution

It introduces a novel antenna selection method ensuring interference constraints in underlay CR, with analytical expressions for performance metrics.

Findings

Closed-form outage probability expressions

Derivation of ergodic capacity formulas

Simulation results confirming analytical analysis

Abstract

Cognitive radio (CR) technology addresses the problem of spectrum under-utilization. In underlay CR mode, the secondary users are allowed to communicate provided that their transmission is not detrimental to primary user communication. Transmit antenna selection is one of the low-complexity methods to increase the capacity of wireless communication systems. In this article, we propose and analyze the performance benefit of a transmit antenna selection scheme for underlay secondary system that ensures the instantaneous interference caused by the secondary transmitter to the primary receiver is below a predetermined level. Closed-form expressions of the outage probability, amount of fading, and ergodic capacity for the secondary network are derived. Monte-carlo simulations are also carried out to confirm various mathematical results presented in this article.