Power Allocation Coefficient Optimization in NOMA in a 5G Perspective

High spectral density, leading to a higher capacity, is an exceedingly desirable feature in wireless communication. Ubiquitous connectivity enabled with machine-to-machine (M2M) communication is a prominent proposal of 5G. Now, to successfully establish M2M communication, a powerful technique is required that can successfully improve the capacity of wireless communication. Several Multiple Access (MA) technologies are available in the literature that are targeted at improving the spectral density. One such technology is Non-Orthogonal Multiple Access (NOMA), which has generated major research interest over the years. NOMA relies on Successive Interference Cancellation (SIC) to decode the user signal. It is observed that optimal allocation of power to the end users can considerably improve the NOMA performance. In the current work, an optimized power allocation technique is derived for a three-user NOMA scenario. Through extensive Monte Carlo simulations, the proposed method is shown to considerably improve the performance of a three-user system under Rayleigh fading and Nakagami – m fading conditions with an Additive White Gaussian Noise (AWGN) in the communication channel. The simulation results are noted to achieve an improved sum-rate, thereby establishing a superiority of the proposed system compared to the existing fixed power allocation NOMA techniques.