Discovery resource grouping for D2D discovery for mitigation of in-band emission in LTE-Advanced

Device-to-device (D2D) communication techniques have drawn considerable interests as one of the most essential features for the next wireless communications. Unlike the traditional cellular system, D2D communication uses a direct communication link between devices in a limited area and it takes additional advantages of spectrum efficiency, low power consumption, and communication even in out of cellular network coverage. In the 3rd Generation Partnership Project (3GPP), the standardization of D2D communication has been started focusing on D2D discovery and direct communication for the Long Term Evolution Advanced (LTE-A) system. Since D2D discovery coexists with physical channels in a given uplink carrier, the potential impacts of D2D discovery to cellular system are of main concern due to half duplexing constraint and in-band emission. Especially, the impact of in-band emission interference from D2D devices is critical in receiving physical uplink control channel (PUCCH) at eNB side and it eventually affects downlink user throughput. In this paper, we propose a new discovery resource grouping scheme. A D2D UE selects one of the two groups of discovery resources based on downlink reference signal received power (RSRP) for the transmission of its discovery signal. The proposed scheme minimizes the number of subframes where PUCCHs are impacted by the in-band emission interference of D2D discovery. Our evaluations show that the proposed scheme is beneficial for the alleviation of in-band emission.