Joint Sensing and Reception Design of SIMO Hybrid Cognitive Radio Systems

TL;DR

This paper proposes a joint design of spectrum sensing and receive beamforming in hybrid cognitive radio systems to maximize uplink rates while ensuring primary user QoS, outperforming traditional methods.

Contribution

It introduces a novel joint design framework for spectrum sensing and beamforming in hybrid CR systems with a realistic CSI model, including a new outage probability approximation.

Findings

Proposed design outperforms traditional underlay and interweave CR systems.

Derived a closed-form approximation for primary outage probability.

Optimized rate selection for hybrid CR operation modes.

Abstract

In this paper, the problem of joint design of Spectrum Sensing (SS) and receive beamforming (BF), with reference to a Cognitive Radio (CR) system, is considered. The aim of the proposed design is the maximization of the achievable average uplink rate of a Secondary User (SU), subject to an outage-based Quality-of-Service (QoS) constraint for primary communication. A hybrid CR system approach is studied, according to which, the system either operates as an interweave (i.e., opportunistic) or as an underlay (i.e., spectrum sharing) CR system, based on SS results. A realistic Channel State Information (CSI) framework is assumed, according to which, the direct channel links are known by the multiple antenna receivers (RXs), while, merely statistical (covariance) information is available for the interference links. A new, closed form approximation is derived for the outage probability of primary communication, and the problem of rate-optimal selection of SS parameters and receive beamformers is addressed for hybrid, interweave and underlay CR systems. It is proven that our proposed system design outperforms both underlay and interweave CR systems for a range of system scenarios.