Polynomial Phase Modulation-Based Code-Domain NOMA

In this paper, we propose a new modulation scheme for downlink non-orthogonal multiple-access (NOMA) transceivers based on polynomial phase signals (PPS). The PPS producing outstanding spectral efficiency and bit error rate (BER) performance. We also propose a design criterion to enable the NOMA system to deploy a large number of users with more flexibility as well as lower design and detection complexity than traditional code-domain NOMA systems. The transmitter involves a low-density code encoder, allowing diversity in different resources to the users. Detection is performed by combining the High-Order Ambiguity Function (HAF) and the Maximum Ratio Combining (MRC) algorithm. Simulation results illustrate that the proposed scheme can not only support a higher number of users, but also achieve a lower bit error rate (BER) than the other CD-NOMA systems.