Efficient small cell discovery mechanism exploiting network synchronization and assistance for future radio access networks

In this paper, we propose an efficient small cell discovery mechanism that addresses two problems: the increases in the UE effort and corresponding battery consumption for inter-frequency small cell discovery due to an increase in the number of frequency carriers to be measured, and the severe interference among synchronization signals (SSs) and reference signals (RSs) transmitted by clustered small cells. The proposed mechanism utilizes synchronized transmission of discovery signals (DS) for the discovery of small cells. In addition, the network informs connected UEs about the transmission timing and configuration information of DSs. Therefore, the proposed mechanism based on network synchronization and assistance can achieve fast and efficient discovery of multiple small cells, if an appropriate DS is applied. To solve the interference among synchronized DSs, the DS design based on existing SS and RS with orthogonal resource configuration is also proposed. Simulation results show that the proposed mechanism with an appropriate DS design can ensure accurate discovery of multiple small cells within a short measurement time.