Optimal Power Allocation for Finite Blocklength Cooperative NOMA With Coordinated Direct and Relay Transmission

In this letter, we study the power allocation problem of cooperative non-orthogonal multiple access (C-NOMA) systems with coordinated direct and relay transmission (CDRT) in the finite blocklength regime. The overall average effective throughput is used as a performance metric to optimize the power allocation of the C-NOMA system with CDRT over Rayleigh fading channels. Specifically, the closed-form expressions of average block error rates and effective throughputs for two users are derived. Then, we derive, for the first time, the optimal power allocation coefficients to maximize the overall average effective throughput at high signal-to-noise ratios. Finally, Monte Carlo simulations are used to verify the correctness of the theoretical analysis.