Full-Duplex Nonorthogonal Multiple Access With Layers-Based Optimized Mobile Relays Subsets Algorithm in B5G/6G Ubiquitous Networks

Abstract

In view of noteworthy communications performance improvements for future B5G/6G ubiquitous networks (such as cognitive Internet of Things (IoT) network, UAV communications, air-space-ground integration network, and so on), cooperative communications (CCs) diversity with relays selection algorithms has been extensively studied to significantly improve communications quality. In light of unsolved millennium issue in CC—nondeterministic polynomial (NP) and NP-hard problems have not been solved efficiently for relays subsets selection, in this article, theorems of relays subsets with <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">${K}$ </tex-math></inline-formula> -layers power allocation standard have been further put forward to explore better performance in B5G/6G networks. We propose unified layers-based optimized mobile relays subsets algorithms for full-duplex (FD) nonorthogonal multiple access (NOMA) to greatly improve transmission rates. After taking into account fundamental properties of relays, such as mobile relays nodes state, relays locations, fading characteristics, and so on, optimized FD-NOMA algorithm based on these relays features has been presented to improve transmission rates, and a related series of relays subsets theorems has been derived and proved, then minimum upper bound of maximum transmission rates is estimated to reveal two-way balanced optimal transmission conclusion for FD-NOMA. Furthermore, simulation results show that proposed algorithm has 1–3 dB advantage than other relays subset algorithms for signal to interference and noise ratio (SINR), and it can more efficiently transform NP-hard problem to P problem for relays selection. Importantly, under revealed two-way balanced optimal transmission phenomenon for FD-NOMA, the proposed scheme with FD-NOMA has more than two times minimum device-to-device (D2D) transmission rates higher than other classical relays selection algorithms.