Cooperative Relaying Using MIMO NOMA

Abstract

Non-orthogonal multiple access (NOMA) is considered to be a significant multiple radio access technology for future wireless networks owing to its improved spectral efficiency. This work proposes two different cases of a downlink two phase cooperative decode-and-forward relaying scheme using multiple-input-multiple-output non-orthogonal multiple access (MIMO-NOMA) systems with the availability of statistical channel state information at the transmitter. Ergodic sum capacities of the proposed cases are provided for independent Rayleigh fading channels. It has been demonstrated that the proposed protocol exhibits superior performance gains than the existing cooperative relaying scheme (CRS) using single-input-single-output NOMA, CRS using multiple-input-single-output NOMA, and conventional CRS MIMO protocols. It is also noticed that the relay position between the transmitter and the receiver can bring a vital change in the performance of the proposed network.