Outage Performance of Cognitive AF Relay Networks with Imperfect CSI Based on Geometrical Analysis

• Published in: Chinese Journal of Electronics Vol. 26; no. 5; pp. 1048 - 1056
• Main Authors: Liu, Shuai, Sun, Dechun, Liu, Zujun, Yi, Kechu, Yang, Hong, Wang, Kan
• Format: Journal Article
• Language: English
• Published: Published by the IET on behalf of the CIE 01.09.2017
• Subjects: amplify and forward communication; analytical lower bounds; asymptotic analysis; channel estimation; closed‐form upper bounds; cognitive AF relay networks; cognitive amplify‐and‐forward relay network; cognitive radio; Cognitive relay networks; diversity order; diversity reception; error statistics; Geometrical analysis; geometrical analysis method; geometry; high signal‐to‐noise ratio regime; high SNR regime; Imperfect Channel state information (CSI); imperfect channel state information estimations; imperfect CSI; outage performance; outage probability; Primary user; probability; Rayleigh channels; Rayleigh fading; relay networks (telecommunication); secondary system; theoretical analysis; outage performance; Imperfect Channel state information (CSI); amplify and forward communication; Geometrical analysis; diversity order; cognitive radio; outage probability; cognitive amplify-and-forward relay network; closed-form upper bounds; error statistics; relay networks (telecommunication); diversity reception; geometrical analysis method; Primary user; Cognitive relay networks; probability; Rayleigh channels; asymptotic analysis; theoretical analysis; secondary system; cognitive AF relay networks; channel estimation; imperfect CSI; imperfect channel state information estimations; high SNR regime; geometry; Rayleigh fading; high signal-to-noise ratio regime; analytical lower bounds
• ISSN: 1022-4653; 2075-5597
• DOI: 10.1049/cje.2017.04.008

This paper studies the outage performance of a cognitive Amplify-and-forward（AF） relay network subject to Rayleigh fading.Under the condition of imperfect Channel state information（CSI） estimations of the links from the secondary system to the Primary user（PU）,the closed-form upper and lower bounds of the outage probability are derived through a geometrical analysis method.An asymptotic analysis of the outage probability is also derived in the high Signal-to-noise ratio（SNR）regime to gain additional insights on the system.The simulation results corroborate our theoretical analysis,and the effectiveness of the geometrical analysis method is verified with the conventional approach as a benchmark.The asymptotic results are very tight with the analytical lower bound in the high SNR regime.It also can be observed from the simulation results that the impact of the number of relays as well as the imperfect CSI on the outage probability and the diversity order.