Non-Orthogonal Multiple Access with Alamouti Technique for Future Wireless Communication

Abstract

Non-orthogonal Multiple Access Scheme (NOMA) is an important candidate in the field of mobile access scheme for advanced wireless networks. In order to improve the NOMA performance the researchers are working on various domains like users pairing, power allocation techniques, decoding techniques etc. we are focusing on various interference cancellation techniques i.e. decoding methods to improve the Bit Error rate (BER) of NOMA. In this article we propose a new hybrid model in which Non-orthogonal Multiple Access Scheme (NOMA) is combined with space time block coding (Alamouti scheme). Our focus is on two transmitter and one receiver (2X1) and two transmitter and two receiver (2X2) Alamouti STBC MIMO NOMA systems. The performance of this hybrid model in multiple input and multiple output technology is investigated in terms of Bit Error Rate (BER) over Rayleigh fading environment. The simulation results of proposed model were compared with maximum-ratio combiner (MRC), Zero Forcing (ZF), Minimum Mean Square error (MMSE) scheme. Further the proposed model is extended with Successive Interference Cancellation (SIC) scheme and results are compared with ZF-SIC and MMSE-SIC. The BER achieved in proposed method is 10– <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">5</sup> where as in other SIC it is up 10∓ <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">3</sup> . This validates that the proposed Hybrid scheme degraded BER compared to OMA and improve the performance of NOMA compare to above mentioned decoding methods.