le transmit and receive antenna exchange their data via a shared relay consisting of large number of antennas. system suffers from SLI and IUI, from the transmit antenna to receive antenna of the relay and user, respectively. system suffers from the inter-pair interference because of multiple users simulta- neously transmitting and receiving in the time/frequency resource. Before discussing the system model in detail, we briefly digress to discuss about the SLI suppression techniques. 4.8.1 SLI Suppression Full-duplex systems, due to its ability to double the SE as compared to half-duplex systems, have recently received significant attention [27, 33-36]. The main hurdle is the SLI, which arises due to transmission and reception on the same time-frequency resource. Recent full-duplex studies, however, have shown that the SLI can be significantly suppressed [2, 3]. There exist many SLI cancellation techniques in full- duplex literature; we will next discuss some of them. 4.8.1.1 Passive Cancellation It was shown in [37, 38] that the passive SLI suppression techniques (cross- polarization, absorptive shielding, and directional isolation) result in significantly reduction in the SLI. In addition if the statistical channel information is known, the authors in [38] showed even an increased level of SI suppression using the passive cancellation techniques. 4 Full-Duplex Multi-Hop Communication for Beyond 5G 4.8.1.2 Large Antenna Array at Relay If we consider a large number of antennas N, the channels between the transmit and receive antenna, i.e., the SLI channel and the desired signal channel, become nearly orthogonal [23]. Therefore, the low complexity linear beamforming techniques, as discussed in earlier sections (MRC/MRT or ZFR/ZFT), project the desired signal to the orthogonal complement space of the SLI, resulting in significant reduction of the SLI. 4.8.1.3 Lower Transmit Power at Relay Reference [23, 25] showed that the SLI is proportional to the relay power, PR. The relay transmit power can be reduced while ma