Outage Performance of NOMA in Cooperative Cognitive Radio Networks With SWIPT

Yuehao Yu,Jamal Ahmed Hussein,Zhicheng Dong,Zheng Yang,Wen-Kang Jia,Yi Wu

doi:10.1109/access.2019.2936321

Abstract

This paper considers the application of non-orthogonal multiple access (NOMA) into cooperative cognitive radio (CR) networks with simultaneous wireless information and power transfer (SWIPT). For NOMA in cooperative CR networks with SWIPT, the cognitive relay harvests the transmission power from the secondary transmitter with power splitting scheme, while the fixed power allocation scheme is used for the NOMA protocol. The closed-form analytical expression of the overall outage probability for the proposed networks is derived, as well as its diversity order at high signal-to-noise ratio (SNR) region is investigated. Furthermore, compared to OMA in cooperative CR networks with SWIPT, the proposed scheme can always achieve the same diversity order, but lower overall outage performance. Compared with NOMA in cooperative CR networks using its own battery for transmission, the SWIPT NOMA in cooperative CR networks will lead to losing a little of the overall outage performance, but without losing the diversity order.

Highlights

Non-orthogonal multiple access (NOMA) has been regarded as an important enabling technology for the fifth generation (5G) wireless networks
Two studies [12], [13] have considered cooperative cognitive radio (CR) NOMA networks, and they have shown that the performance of the secondary receivers can be significantly improved compared to OMA in cooperative CR networks
OVERALL OUTAGE PROBABILITY FOR simultaneous wireless information and power transfer (SWIPT)-BASED NOMA IN COOPERATIVE CR NETWORKS we focus on the fixed power allocation scheme at the secondary relay in the cooperative CR-NOMA networks with SWIPT, where more power is allocated to the far user than the near user to enhance the fairness among users

Summary

INTRODUCTION

Non-orthogonal multiple access (NOMA) has been regarded as an important enabling technology for the fifth generation (5G) wireless networks. The authors in [17], have studied a wireless-powered uplink communication system with NOMA for one base station and multiple energy harvesting users. In their investigations, a greedy algorithm has been proposed for the time-sharing strategy to optimize the performance and user fairness of the wireless-power NOMA networks. When the maximal interference tolerant level from the secondary transmitter and the cognitive relay to the primary receiver is proportional to the maximal transmission power at the secondary transmitter, the SWIPT NOMA/OMA in cooperative CR networks can achieve the same diversity gain, but the overall outage probability of the former is lower than that of the latter. The overall outage performance, but without losing any diversity gain

SYSTEM MODEL

NUMERICAL RESULTS

CONCLUSIONS