A novel power control based on a relaxed constraint in cognitive system

Abstract

The next‐generation 5G networks will integrate two technologies, cognitive radio and cooperative communication, which use radio spectrum opportunistically and efficiently. In addition, they enhance the reliability and the capacity of the system. In this paper, we present a novel power control scheme based on a relaxed constraint in cognitive network under both the outage probability limit (OPL) of the primary system and the interference constraint limit (ICL). We show how to transform the optimization problem of the condition on the OPL and the ICL into a condition on the channel so that the cognitive user observes the channel from cognitive source to primary receiver and control its transmit power based on the channel condition. Moreover, we extend the studies to the cognitive relay network. We derive the closed‐form expressions of the outage probabilities over independent but not necessarily identically distributed Nakagami‐m fading channels. By using the theoretical analysis and from the numerical results, firstly, we show that the proposed power control scheme, which is based on both the OPL and the ICL, achieves better performance in underlay spectrum rather than the traditional one, which is based only on the interference constraints. Secondly, we show that the proposed scheme allows lower power consumption at cognitive side while the performance of cognitive relay network is improved, and the QoS of primary system is guaranteed in parallel. Copyright © 2016 John Wiley & Sons, Ltd.

A Survey on Compressive Spectrum Sensing for Cognitive Radio Networks

“…There exist two popular mode of spectrum access in CRN are underlay and interweave. In the first approach, the secondary user (SU) can transmit simultaneously with primary user (PU) over the same radio frequencies (RF) spectrum, while minimizing interferences with primary users , i.e., if the interference generated by SU at primary receiver is tolerable and controlled by an acceptable level [1] [2]. In the second approach, the SU does not interfere with PU.…”