BER Analysis for Lattice-Partition-Based Downlink Non-Orthogonal Multiple Access Systems

Lattice partition (LP) is a promising technique to design power-domain non-orthogonal multiple access (NOMA) systems because it can approach the capacity region with reduced receiver complexity. Most of LP-based NOMA works have been focused on outage and capacity analyses. In this letter, theoretical expressions of the bit error rate (BER) are derived for a two-user LP-based NOMA system using bipolar pulse amplitude modulation. The derived BERs agree well with computer simulation results. Since a two-dimensional LP-based NOMA signal can be decomposed into two orthogonal one-dimensional LP-based NOMA signals, the analytical results can be easily extended to a quadrature-amplitude modulation case.