Beam division multiple access for millimeter wave massive MIMO: Hybrid zero-forcing beamforming with user selection

<p>Massive multiple-input multiple-output (MIMO) systems are considered a promising solution to minimize multiuser interference (MUI) based on simple precoding techniques with a massive antenna array at a base station (BS). This paper presents a novel approach of beam division multiple access (BDMA) which BS transmit signals to multiusers at the same time via different beams based on hybrid beamforming and user-beam schedule. With the selection of users whose steering vectors are orthogonal to each other, interference between users is significantly improved. While, the efficiency spectrum of proposed scheme reaches to the performance of fully digital solutions, the multiuser interference is considerably reduced.</p>

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>

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>