Abstract: Densely deployed small cells suffer from the problem of severe co-channel interference among the neighbouring cells and user equipments (UEs) in the network are confronted with a challenge of intensive energy consumption in inter-frequency scanning (IFS). In order to deal with the problems, a time of arrival (TOA) fingerprint database based small cell discovery strategy was proposed, where the synchronization reference signals (primary synchronization signal/secondary synchronization signal, PSS/SSS) of small cells are transmitted in a flexible scheme. The proposed method achieves the purpose of energy saving for UE by tremendously reducing the number of invalid inter-frequency detection. Meanwhile, it is capable of alleviating the co-channel interference of synchronization signals among small cells through flexible control of PSS/SSS transmission. Simulation shows that the proposed method can effectively improve the probability of detecting small cells and the energy efficiency of UEs in the network.

Key words: small cells discovery, interference cancellation, fingerprint database, inter-frequency scan