On The Selection of Power Allocation Strategy in Power Domain Non‐Orthogonal Multiple Access (PD‐NOMA) for 6G and Beyond

Abstract

Abstract Non‐orthogonal multiple access (NOMA) is an attractive candidate for 6G networks to support ultra‐massive machine‐type communications (umMTC). Power domain NOMA (PD‐NOMA) is the simplest type of NOMA, which assigns a different power level to each user. Power allocation in PD‐NOMA can be classified into fixed/dynamic power allocation (FPA/DPA). FPA is simple, but DPA is more suitable for the mobile environment than FPA. However, finding optimum power per each user in DPA is extremely complex. Fortunately, many DPA strategic design methods were introduced in literature as simple suboptimal solutions of DPA. Therefore, DPA strategic design methods and FPA techniques are simple approaches to implement PD‐NOMA in 6G and beyond. In literature, no previous work had compared the performances of all DPA strategic design methods, nor FPA techniques, to ease the selection of a simple strategy for PD‐NOMA in 6G. Motivated by that, this work compares performances of all DPA strategic design methods as well as FPA techniques, in terms of sum‐rate capacity, fairness, and bit error rate (BER). Results showed that the best DPA strategic design method and the best FPA technique have comparable performance.