A New Rate Splitting Strategy for Uplink CR-NOMA Systems

• Published in: IEEE transactions on vehicular technology Vol. 71; no. 7; pp. 7947 - 7951
• Main Authors: Liu, Hongwu, Bai, Zhiquan, Lei, Hongjiang, Pan, Gaofeng, Kim, Kyeong Jin, Tsiftsis, Theodoros A.
• Format: Journal Article
• Language: English
• Published: New York IEEE 01.07.2022; The Institute of Electrical and Electronics Engineers, Inc. (IEEE)
• Subjects: Cognitive radio; cognitive radio (CR); Decoding; Interference; Interference cancellation; NOMA; non-orthogonal multiple access (NOMA); Nonorthogonal multiple access; outage probability; Outages; Power control; Power system reliability; Quality of service; Rate splitting (RS); Resource management; Splitting; Uplink; Uplinking
• DOI: 10.1109/TVT.2022.3166218
• ISSN: 0018-9545

In uplink non-orthogonal multiple access (NOMA) channels, the existing cooperative successive interference cancellation (SIC) and power control (PC) schemes lack the capability of achieving the full capacity region, which restricts the outage performance of uplink NOMA users. For the uplink cognitive radio inspired NOMA system, we propose a new rate splitting (RS) strategy to maximize the achievable rate of the secondary user without deteriorating the primary user's outage performance. Based on the interference threshold and its own channel gain, the secondary user adaptively conducts RS, transmit power allocation and SIC, which utilizes the transmit power efficiently. The closed-form expression for the outage probability is derived for the secondary user. Numerical results show that the proposed RS scheme achieves the best outage performance for the secondary user among the existing cooperative SIC and PC schemes.