US Patent 9936373 Discovery signals in heterogeneous wireless networks

In a heterogeneous network deployment that includes a macro base station and one or more low power nodes, a discovery signal is transmitted to facilitate the identification of low power nodes. The discovery signal is transmitted on a selected subset of resource elements, previously unused, to maintain backward compatibility with legacy user equipment. The transmission sequence and/or the locations of resource elements used for transmitting the discovery signal can identify the low power node to a user equipment.