Efficient Sidelink Identity Detection and Frequency Ambiguity Resolution for LTE-D2D Communications

Device-to-device (D2D) communication is a key enabler to facilitate the realization of the Internet of Things (IoT) in which devices directly communicate with each other. One of the major challenges in the D2D network is robust and low-cost synchronization for ultra-reliable low latency communication. To address this issue, this paper presents an efficient frequency ambiguity resolution and sidelink synchronization identity detection scheme for D2D communications in the long term evolution system. To perform low-cost joint detection, the proposed method is based on the grouping of the primary sidelink synchronization sequence (PSSS) subcarriers. The PSSS subcarriers are grouped into a number of subsets wherein the phase difference between the PSSS subcarriers is approximately a multiple of π/2. Numerical analysis is performed to present the relationship between detection probability and design parameter. Simulations show that the proposed method has the same performance as the existing detection method, with significantly reduced computational complexity.