Power Allocation for NOMA with Cache-Aided D2D Communication

• Published in: IEEE transactions on wireless communications Vol. 23; no. 1; p. 1
• Main Authors: Shen, Kevin Z., So, Daniel K. C., Tang, Jie, Ding, Zhiguo
• Format: Journal Article
• Language: English
• Published: New York IEEE 01.01.2024; The Institute of Electrical and Electronics Engineers, Inc. (IEEE)
• Subjects: Communication networks; Communications equipment; Device-to-device communication; device-to-device communications (D2D); Downlink; Downlinking; Interference; Interference cancellation; NOMA; non-orthogonal multiple access (NOMA); Nonorthogonal multiple access; Optimization; Power management; Receivers; Resource management; Sum rate maximization; Video on demand; wireless caching; Wireless communication
• ISSN: 1536-1276; 1558-2248
• DOI: 10.1109/TWC.2023.3279266

Communication networks are becoming increasingly content-centric, and reusable content like viral information and video on demand are often requested by multiple users. Caching at the user equipment enables device-to-device (D2D) communications to be used to deliver requested contents which will help reduce data traffic at base stations and also enhance the achievable data rates. In this paper, we propose a system whereby users are able to exchange valuable cached content with each other via a D2D link which underlays the reception of a downlink non-orthogonal multiple access (NOMA) signal. We formulated a sum rate maximization problem that is subject to minimum rate constraints and derived optimal solutions depending on which user is the D2D transmitter. Additionally, sub-optimal solutions based on a negligible self-interference assumption are also proposed. Simulation results demonstrate the significant performance gains of underlaid D2D communications as compared with optimal downlink cellular NOMA. Furthermore, results on the self-interference (SI) cancellation factor highlight that the sub-optimal power allocation solution offers sum rate performance close to the optimal case. The performance gains are further enhanced when SI cancellation is high.