Reference signal design for LTE-based D2D communications

D2D (device-to-device) communications allow the terminals to establish direct connections without the intervention of the BS (base station), when the transmitter and the receiver are in close proximity. Considering the benefits such as spatially reusing licensed spectrum in cellular networks and directly connecting beyond the coverage of BSs, this feature should have fit the LTE (long term evolution). However, related literature mainly concentrated on resource allocation and energy efficiency. There is almost no literature majoring in the air interface of D2D-fitting LTE, the RS (reference signal) and the RS pattern design. The current paper targets at filling these gaps by adopting LTE uplink SC-FDMA (single-carrier frequency-division multiple access) as the air interface, the DMRS (demodulation reference signal) as the original RS and the proposed RS design as our new RS pattern. Simulation results prove the effectiveness of the proposed D2D RS scheme.