Efficient NOMA Design without Channel Phase Information using Amplitude-Coherent Detection

<div>This paper presents the design and bit error rate (BER) analysis of a phase-independent non-orthogonal</div><div>multiple access (NOMA) system. The proposed NOMA system can utilize amplitude-coherent detection</div><div>(ACD) which requires only the channel amplitude for equalization purposes. In what follows, three</div><div>different designs for realizing the detection of the proposed NOMA are investigated. One is based on the</div><div>maximum likelihood (ML) principle, while the other two are based on successive interference cancellation</div><div>(SIC). Closed-form expressions for the BER of all detectors are derived and compared with the BER of</div><div>the coherent ML detector. The obtained results, which are corroborated by simulations, demonstrate that,</div><div>in most scenarios, the BER is dominated by multiuser interference rather than the absence of the channel</div><div>phase information. Consequently, the BER using ML and ACD are comparable for various cases of</div><div>interest. The paper also shows that the SIC detector is just an alternative approach to realize the ML</div><div>detector, and hence, both detectors provide the same BER performance.</div><div><br></div>