Joint Power Allocation for NOMA-Based Diamond Relay Networks With and Without Cooperation

Abstract

Non-orthogonal multiple access (NOMA)-based diamond relaying (NDR) is an efficient approach for combining NOMA and relaying techniques in such a way as to enhance the achievable rate from the source to the destination in the network. This paper examines the problem of joint power allocation among all the transmission phases during the operation of such networks. Based on the Karush-Kuhn-Tucker (KKT) condition and the second-order sufficient condition (SOSC), at least the local optimal solution is derived and analyzed. In addition, a new protocol for NDR networks based on cooperative communications is introduced and the associated joint power-allocation problem is examined. It is shown that this cooperative NDR (C-NDR) network further improves the achievable rate in some typical placements of the relays. Simulation results verify the correctness of the deviation and confirm the effectiveness of the proposed joint power-allocation method for both NDR and C-NDR networks. INDEX TERMS Non-orthogonal multiple access (NOMA), relay networks, NOMA-based diamond relaying (NDR), cooperative communications, Karush-Kuhn-Tucker (KKT) condition, second-order sufficient condition (SOSC), joint power allocation, achievable rate.

Cooperative Power Domain Noma Transmission Using Relays

“…As an effective means to improve the system efficiency full-duplex (FD)-NOMA, the same study has been explored together with buffer-aided (BA) relay grids, incorporated with NOMA and broadcasting technique. To ensure consistency with enhancing system efficiency and achievable rate, Huang and Lee [11] proposed NOMA-based diamond relay cooperative and non-cooperative. Balyan and Daniels [12] performed resource allocations with the help of relays.…”

“…The SIC will be employed by any p th user to detect its own signal [21] and the achievable rates will be calculated using Eqs. ( 9)- (11).…”

Improved Error Performance in NOMA-based Diamond Relaying

“…( 10)] for only Rayleigh fading channels. By substituting these equations into (12) and then by substituting ( 12) into ( 9), the BER of the NOMA-DRN with the JML is obtained.…”

“…Moreover, when two relays are located between the source and the destination, as a subset of NOMA-CRS, called NOMA-based diamond relaying network (DRN) is proposed in [11] and the sum-rate expression is derived. Then, the optimum power allocation is studied in [12] to maximize the sum-rate of the NOMA-DRN. However, when the error probability of the NOMA-DRN is analyzed, it is seen that the NOMA-DRN has a poor error performance [13].…”