Claims:1. A apparatus of user equipment (UE) configured for direct device-to-device (D2D) communication with one or more other UEs, the apparatus comprising: transceiver circuitry; and
processing circuitry, configured to:
receive, from an enhanced node B (eNB), an allocation of resources for D2D communication;
modulate control information, for a D2D transmission within resource elements (REs) of a physical D2D control channel, in accordance with a single-carrier frequency division multiplexing (SC-FDM) technique;
modulate data, for a D2D transmission within REs of a physical D2D shared channel, in accordance with the SC-FDM technique;
provide synchronization information for the D2D transmissions, the synchronization information based on signaling; and
generate a demodulation reference signal (DMRS) for transmission within the resources allocated by the eNB for D2D communication, the DMRS configured for demodulation of the physical D2D control channel and the physical D2D shared channel,
wherein the REs of the physical D2D control channel and the REs of the physical D2D shared channel are within the resources allocated by the eNB for D2D communication.
, Description: Device-to-device (D2D) communications is one means for improving the performance of LTE (Long Term Evolution) and other cellular networks. In D2D communications, terminals (referred to as user equipments or UEs in LTE) communicate with one another directly rather than being linked through the base station (referred to as an evolved node B or eNB in LTE). D2D communication between two or more D2D devices is typically very local, due to the short distance between D2D devices and uses very lower transmit power. D2D communications is also a powerful way to increase spatial reuse in cellular systems for higher throughput.

[0003] One approach to D2D communications as an underlay to an LTE network infrastructure is an out-of-band solution, in which the D2D traffic is unloaded to an unlicensed band (e.g., Wi-Fi as defined by the IEEE 802.11 standards) on the application layer. Another approach is an in-band solution, in which the D2D transmissions take place in the same licensed band used by the LTE network. The present disclosure deals with aspects of the in-band approach to D2D communications. In particular, the focus is on a signal structure for supporting in-band D2D communications, scheduling of D2D transmissions, and power control for interference management.