An Evaluation of the Coverage Region for Downlink Non-orthogonal Multiple Access (NOMA) Based on Power Allocation Factor

Abstract

Non-Orthogonal Multiple Access (NOMA) is<br><br>known as one of the promising techniques in the fifth generation<br><br>of wireless communication. The classification of users in (NOMA)<br><br>is based on power, while it is based on time, frequency and code<br><br>in Orthogonal Multiple Access (OMA). In this study the<br><br>downlink NOMA includes two users, one strong and one weak.<br><br>The comparison of NOMA and OMA properties shows a range of<br><br>Power Allocation Factors (PAF) for the two users within which<br><br>NOMA properties have proved to be better than OMA. It was<br><br>also shown that the achieved PAF is a function of channel gains<br><br>of two users. Then, the coverage region is defined for multiple<br><br>access channel; and by considering the Base Station (BS) as a<br><br>fixed one in the center of the cell, the coverage region for both<br><br>NOMA and OMA is calculated. The theoretical and analytical<br><br>results show that the achieved coverage region of NOMA for both<br><br>weak and strong users has been increased compared to OMA.