On the Performance of NOMA-OFDM Systems with Time-Domain Interleaving

Non-orthogonal multiple access (NOMA) based on orthogonal frequency division multiplexing (OFDM) multicarrier modulation technique is a promising multiple access scheme for next-generation wireless communication systems. This paper analyzes the bit error rate (BER) performance of a downlink power domain NOMA-OFDM system with time-domain interleaving (TDI) over frequency selective Rayleigh channel. Theoretical BER expressions for a downlink power domain NOMA-OFDM system with TDI and using minimum mean squared error (MMSE) equalizer are developed for an arbitrary number of users. The Monte Carlo simulation results show that the proposed downlink power domain NOMA-OFDM system with TDI has better BER performance over frequency-selective fading multipath channels compared to the conventional NOMA-OFDM system without TDI.