Title :
Performance Analysis of Cognitive Relay Networks Over Nakagami-
Fading Channels
Author :
Xing Zhang ; Yan Zhang ; Zhi Yan ; Jia Xing ; Wenbo Wang
Author_Institution :
Wireless Signal Process. & Network Lab., Key Lab. of Universal Wireless Commun., Beijing, China
Abstract :
In this paper, we present performance analysis for underlay cognitive decode-and-forward relay networks with the Nth best relay selection scheme over Nakagami-m fading channels. Both the maximum tolerated interference power constraint and the maximum transmit power limit are considered. Specifically, exact and asymptotic closed-form expressions are derived for the outage probability of the secondary system with the Nth best relay selection scheme. The selection probability of the Nth best relay under limited feedback is discussed. In addition, we also obtain the closed-form expression for the ergodic capacity of the secondary system with a single relay. These expressions facilitate in effectively evaluating the network performance in key operation parameters and in optimizing system parameters. The theoretical derivations are extensively validated through Monte Carlo simulations. Both theoretical and simulation results show that the fading severity of the secondary transmission links has more impact on the outage performance and the capacity than that of the interference links does. Through asymptotic analysis, we show that the diversity order for the Nth best relay selection scheme is min(m1, m3) × (M - N) + m3, where M denotes the number of cognitive relays, and m1 and m3 represent the fading severity parameters of the first-hop transmission link and the second-hop transmission link, respectively.
Keywords :
Monte Carlo methods; Nakagami channels; channel capacity; cognitive radio; decode and forward communication; interference suppression; optimisation; probability; radio links; relay networks (telecommunication); Monte Carlo simulation; Nakagami-m fading channels; Nth best relay selection scheme; asymptotic analysis; cognitive decode-and-forward relay networks; ergodic capacity; fading severity parameters; maximum tolerated interference power constraint; maximum transmit power limit; outage probability; secondary system; selection probability; system parameter optimization; transmission link; Decoding; Fading; Interference; Quantization (signal); Relay networks (telecommunications); Signal to noise ratio; $N$th best relay selection; Cognitive relay networks; Nakagami- $m$ fading; Nakagami-m fading; Nth best relay selection; ergodic capacity; outage probability;
Journal_Title :
Selected Areas in Communications, IEEE Journal on
DOI :
10.1109/JSAC.2014.2361081