US Patent 9622170 Wireless communication in heterogeneous networks

Systems, methods, and apparatuses for energy saving in heterogeneous wireless communication networks are provided. The small cell (e.g., pico cell, relay cell, femto cell) may adjust its transmit power based on the requirement of user equipments (UEs) in the cell's coverage. The small cell may detect a UE entering its coverage with or without assistance from the macro cell. An appropriate small cell may be selected to serve the UE based on its traffic load when the UE is located in the coverage of multiple small cells. The small cell may also transmit auxiliary synchronization signals to reduce the association time for the UE.