Performance Analysis of a Relay-Assisted D2D Underlay Cellular Network

Device-to-device (D2D) underlay cellular network allows spectrum reuse that improves the spectral efficiency of the network. The challenge in allowing D2D links or relay-assisted D2D links to use the same resources as the traditional cellular down/uplink transmissions is the mutual interference between them. The cellular link contributes majorly to the interference due to the high power transmitted over the link. In this work, we consider interference due to cellular transmission at the relay and destination node of the relay-assisted D2D link are mitigated using decoding matrices obtained using interference alignment techniques. The exact expressions of the end-to-end outage probability and symbol error probability are obtained. The analysis is presented for a general scenario with multiple transmit and receive antennas. Numerical results are plotted to show the impact of the modulation order, interference due to other D2D devices, and power transmitted at the source and relay nodes.