Multi-pair device-to-device communications with space-time analog network coding

Device-to-device (D2D) communication, which enables a user equipment to communicate with another nearby UE directly over a D2D link without going through the central base station (BS), have attracted great research interests for future applications on high data rates and spectral efficiency. In this work, we investigate multi-pair D2D communications with a multiple antenna relay under three possible schemes: (i) Direct D2D transmission; (ii) Multi-hop D2D with analog network coding where the relay will help multi-pair D2D transmission by amplify-and-forwarding mixed received signals; (iii) Multi-hop D2D with space time analog network coding where the relay will help multi-pair D2D transmissions by amplify-and-forwarding mixed received signals together with space time coding techniques. Specifically, three pairs of D2D communications with a two-antenna relay are modeled and space-time analog network coding based on Alamouti scheme is applied. We compare the D2D sum rate and bit error rate performance of different schemes under different channel scenarios.