A new channel structure and power control strategy for D2D discovery in LTE cellular network

Device-to-device (D2D) discovery in long-term evolution (LTE) cellular network is a major issue in recent 3rd generation partnership project (3GPP) standardization meeting to support commercial/social services and public safety in disaster environment. For the D2D discovery signal transmission, physical uplink shared channel (PUSCH)-like channel structure is being generally considered. In such a channel structure, the discovery signal may be multiplexed with cellular physical uplink control channel (PUCCH) signal in frequency division multiplexing (FDM) manner. In contrast to cellular PUCCH signal, however, typical open-loop power control is still not considered for D2D discovery signal in order to guarantee the sufficient discovery range, thus inter-carrier interference (ICI) from the discovery signal may severely interfere with the reception of cellular PUCCH signal at evolved node B (eNB). Thus in this paper, we analyze the effect of the ICI in D2D discovery scenario, and evaluate two traditional solutions: the use of guard-band and the application of open-loop power control for discovery signal. Considering disadvantages of the two traditional solutions, we propose a new discovery channel structure and power control strategy for discovery signal transmission in which adaptive open-loop power control based on PUCCH scheduling information is applied. By extensive computer simulation, we verify that the proposed method guarantees relatively high signal-to-interference plus noise power ratio (SINR) of both PUCCH signal and discovery signal.