Role Switching and Power Allocation Technique for Mobile Users in NOMA

TL;DR

This paper introduces a novel role switching and power allocation method for mobile NOMA users to address user mobility challenges, improving capacity by dynamically adjusting user roles and power distribution.

Contribution

It proposes the optimized power role switching-NOMA (OPRS-NOMA) technique, combining role switching based on channel gains with a bisection search power optimization for mobile users.

Findings

OPRS-NOMA outperforms conventional NOMA and OMA in capacity.

Role switching effectively addresses NOMA principle violations caused by user mobility.

Simulation results validate the proposed method's superiority in dynamic scenarios.

Abstract

In this letter, role switching and power allocation schemes are proposed to tackle user mobility in non-orthogonal multiple access (NOMA) systems. When cell center user (CCU) and cell edge user (CEU) come very close or even cross each other in NOMA pairing, channel gains of paired users violate the basic NOMA conditions. This article refers to such condition as NOMA principle violation problem (NPVP). To solve this NPVP, optimized power role switching-NOMA (OPRS-NOMA) technique is proposed. Role switching technique is used where roles of mobile users are switched on the basis of their channel gains. Furthermore, a power allocation scheme based on bisection search power optimization is presented to maximize the average sum capacity of mobile NOMA users. Random way point mobility model is considered for user mobility. Individual and sum capacity are used for performance evaluation. Simulation results show that OPRS-NOMA outperforms the conventional NOMA and orthogonal multiple access (OMA).