Chaos MIMO-based downlink non-orthogonal multiple access scheme with physical layer security

Recently, owing to the rapid increase of wireless traffic on smartphones and tablets, higher-capacity wireless communication systems have been developed. The non-orthogonal multiple access (NOMA) scheme has been studied as one of the potential solutions. In addition to the need for higher capacity, the demand for secure wireless transmission has also grown. To meet these requirements, we propose a chaos multiple-input multiple-output (C-MIMO) scheme that realizes both physical layer security and channel coding gain. In this paper, we apply the principle of C-MIMO to the NOMA scheme, and propose a chaos NOMA scheme that achieves higher-capacity, enabling a secure downlink wireless communication system. By performing numerical simulations, we show that compared to conventional power-domain NOMA schemes, we obtain improved performances and the physical layer security effect by introducing the C-MIMO principle into NOMA. In addition, we show that the throughput enhancement is obtained in the proposed scheme compared to previously proposed chaos orthogonal frequency-division multiple access (C-OFDMA) scheme.