Advances in Device-to-Device Communications and Network Coding for IMT-Advanced

In this paper, we introduce two innovative concepts which have not been present in cellular systems for IMT-Advanced so far: Device-to-device (D2D) communication and network coding. Both of them are promising techniques to increase the efficiency of cellular communication systems, especially from a network point of view. First, we study the potential gains from D2D communication as an underlay to the downlink of a cellular network in an interference limited multi-cell indoor scenario. Our results show that multi-antenna receivers are required to achieve sufficient SINRs that allow device-to-device communication when the D2D connections re-use cellular resources within the cell. Then we investigate applying network coding for cooperative transmission and relay-based communications in networks. For the cooperative transmission, we propose to combine wireless diversity and the capability of increasing max-flow of network coding. We show designed non-binary network codes can substantially decrease outage probability and frame error rate (FER). For the relay based networks, we propose a novel network coding protocol applied to uplink cellular traffic protocol with an efficient decoding approach at the receiver. We complement this method with user grouping in order to make better use of the application of network coding. We show that user grouping in a multi-user networks improves substantially the capacity of network coding.