Optimal Power Allocation in Poisson Shot-Noise-Limited M-ary PPM Photon-Counting NOMA Systems

This data is related to the submitted paper Optimal Power Allocation in PoissonShot-Noise-Limited M-ary PPMPhoton-Counting NOMA Systems byYongkang Chen, Xiaolin Zhou, Haitao Zhou, Dailing Shen, Chongbin Xu,Xin Wang, and Lajos Hanzo.We formulate the power allocation optimization problem of nonlinear discrete-time Poisson (DTP) multiple-access channels (MAC), which is easier than reconfiguring the modulation mode or the duty cycle of signaling. We tackle the challenge is that discrete Poisson shot noise results in MAC mutual information expressions in a series form by deriving a closed-form expression in the low-power scenario for solving the optimization problems formulated. As a benefit of the optimal power-allocation, the average photon efficiency is improved by 1dB to 3dB in comparison to the equal-power benchmark scheme. We also formulate a second optimization problem for minimizing the power required, which becomes as low as 1/3 of that associated with the equal-power benchmark. The proposed scheme is eminently suitable for a variety of background noise conditions or user rate requirements.