NOMA Combined with RC for Reliable and Secure Transmission in a Delay-Constrained System

This letter proposes a Rateless codes (RC)-aided reliable and secure beam-forming scheme for a multiple input single output (MISO) delay-constrained system, combined with non-orthogonal multiple access (NOMA) technique. Total delay of the system is constraint by the number of slots ( N_{TS} ) for which the source can transmit. To satisfy delay-constraint conditions, source uses NOMA to send two encoded packets in a single slot, and also exploits artificial noise (AN) for secure communication. In RC-aided communication, receiver can recover the source file when the received generator matrix is full rank. By using this characteristic of the RC, we determine the delay violation property (DVP) and the information intercept probability (IP) of the proposed system. We also determine the average number of packets that can be decoded successfully in N_{TS} transmissions. Results show that this beam-forming technique using NOMA gives a significant rise in the number of packets decoded successfully at the legitimate receiver, leading to a more reliable and secure communication as compared to the system without using NOMA.