Device-to-device and mobile user communication with queuing in NOMA-based network

In this paper, device-to-device (D2D) pairs use the uplink resource of a mobile user. The transmission is done using a non-orthogonal multiple access (NOMA) technology. The D2D pairs are placed in a queue with maximum threshold time. The channel is allocated to D2D pairs using the TDMA scheme with the first in first out (FIFO) principle. Considering the slots of time division multiple access (TDMA) and channel state, the channel is shared by one D2D pair with the mobile user. The signal to interference (SIC) is employed for D2D pair or mobile user based on NOMA. A hybrid of TDMA and NOMA is used in which time and bit allocation are judiciously adopted. The results are simulated for four different scenarios of power and rate requirements with reduced latency and interference.