Abstract—Cooperative Non-orthogonal multiple access (NOMA) is an effective solution to prevent the degradation in performance of the far users, by allocating less power to users with better channel conditions. The challenge for the base station is to decide how to allocate the power among the individual information waveforms, so we proposed cooperative NOMA in downlink MU-MIMO beamforming based on the signal to leakage ratio (SLR), to achieve power domain between the superposition users signal. We aim to minimize the total transmit power by exploiting the solution of the maximal signal to leakage ratio (maximal-SLR) for each user to find the minimum transmit power per user. sequentially, the best user’s channel will assigned in the first-time slot channel because there is a better channel for each user when the precoder with less transmits power. Order Successive Interference Cancellation (OSIC) and Maximum-likelihood (ML) estimator method are employed at the receiver. Rician fading channels are considered as second-time slot channel. Bit error rate (BER) performance evaluations show that the minimizing the total transmitted power in cooperative NOMA beamforming based on maximal-SLR scheme (MinP-NOMA-MaxSLR) (proposed scheme) is outperforming cooperative NOMA beamforming based maximal-SLR (NOMA-MaxSLR).
 

Index Terms—NOMA, Beamforming, signal-to-leakage ratio, cooperative NOMA, OSIC.

Cite: Mohammed Fadhil, Nor Fadzilah Abdullah, Mahamod Ismail, Rosdiadee Nordin, Abduljalil Saif, and Musaab Al-Obaidi, "Power Allocation in Cooperative NOMA MU-MIMO Beamforming Based on Maximal SLR Precoding for 5G," Journal of Communications, vol. 14, no. 8, pp. 676-683, 2019. Doi: 10.12720/jcm.14.8.676-683