Effects of spatial correlation on QoS‐driven power allocation over Nakagami‐m fading channels in cognitive radio systems

Abstract

Cognitive radio (CR) technology is a revolutionary wireless communication paradigm that targets at the efficient and flexible utilization of the limited radio spectrum resource. This paper considers a spectrum underlay CR system operating in a fading environment, where the secondary users (SUs) have specific communication quality requirements. In this system, the unlicenced SUs may coexist with the licenced primary users, as long as the average interference‐power that they cause to the primary users does not exceed a threshold value.The concept of spatial correlation (cross‐correlation) of Nakagami‐m fading channels is introduced in the quality of service‐driven CR system. Specifically, we present a power allocation scheme that aims at maximising the SU's effective capacity, and we study the effects of the spatial channel correlation on the performance of the proposed scheme. In order to investigate thoroughly the impact of fading correlation, two different scenarios are studied, depending on which links are considered correlated, the receive correlation model and the transmit correlation model. The performance of the proposed allocation scheme is evaluated through simulations. Finally, the effects of spatial channel correlation for different system requirements and scenarios are presented and discussed. Copyright © 2013 John Wiley & Sons, Ltd.

Optimal power allocation over parallel Gaussian channels in cognitive radio and jammer games

“…Until recently, the problem of optimal power allocation in CR networks (CRNs) has been studied to solve either the primary and secondary users (SUs) coexistence [1–4] or the spectrum sharing between the CR users [5, 6]. In [1], the goal is to maximise the weighted sum effective capacities of the SUs.…”

“…The authors determined the optimal power allocation through a convex optimisation method using Lagrangian functions with respect to Karush–Kuhn–Tucker (KKT) conditions. Poulakis et al [2] studied the impact of channel correlation on the optimal power allocation strategy. Multiple‐input–single‐output antenna techniques and antenna selection techniques are studied in [3] to combat the interference constraint and improve the capacity of the SU.…”

QoS‐driven spectrum sharing game in cognitive radio systems: a variational inequality approach

“…Effective capacity represents the maximum constant arrival rate that the channel can sustain to guarantee a specific delay QoS requirement. This concept has been adopted for the development of efficient resource allocation techniques in various wireless networks and recently in CR networks . In this paper, we propose a novel QoS‐driven spectrum sharing (QSS) scheme for an interweave CR system.…”