Next-Generation Multiple Access Based on NOMA With Power Level Modulation

To cope with the explosive traffic growth expected in next-generation wireless networks, it is necessary to design multiple access techniques that can provide higher spectral efficiency as well larger-scale connectivity. As a promising candidate, power-domain non-orthogonal (NOMA) has been widely studied. In conventional NOMA, users are multiplexed same time and frequency band different preset power levels, which, however, may limit under practical finite alphabet inputs. Inspired by concept of spatial modulation, we propose solve this problem encoding extra information bits into exploiting signal constellations help receiver distinguish between them. convey idea, termed selection (PS)-NOMA, clearly, consider simple downlink two-user NOMA system input constellations. Assuming maximum-likelihood detection, derive closed-form approximate bit error rate (BER) expressions for both users. Moreover, achievable region also characterized. Simulation results verify analysis show proposed PS-NOMA outperform terms BER rate.