Methods and apparatus for efficient co-existence of macro and small cells

摘要

A femto base station (BS) maintains two different timings: a femto BS downlink timing and a femto BS uplink timing. A femto base station's uplink reference timing is based on the macro uplink timing being used by one or more UE devices in the local vicinity of the femto BS. In some embodiments, the femto BS synchronizes its femto uplink timing to the macro uplink timing being used by the closest UE device transmitting uplink signals to the macro BS. In other embodiments, the femto BS determines its femto base station uplink timing based on one or more uplink signals from UE devices in its vicinity transmitting to the macro BS. In various embodiments, femto cell uplink signals and macro cell uplink signals are received at a femto cell BS in synchronization. This approach facilitates frequency division multiplexing (FDM) in the uplink between a macro cell and a femto cell.

主权项

1. A method of operating a femto base station within a coverage area of a macro base station, the method comprising:
determining the arrival times at said femto base station of a first signals transmitted to said macro base station by different user equipment (UE) device, said multiple signals including a first signal transmitted by a first user equipment (UE) device to said macro base station and additional signals transmitted by other different UE devices; generating, at said femto base station, a femto base station uplink reference time based on said determined arrival times at said femto base station of the multiple signals including said first signal transmitted to said macro base station, said generating including generating an average arrival time based on the arrival time of said first signal and the arrival times of said additional signals transmitted to said macro base station by said other different UE devices and using the average arrival time to generate said femto base station uplink reference time, said additional signals used in generating said average arrival time being signals that are received at the femto base station at a power level above a predetermined threshold indicating that the UE devices which transmitted the additional signals are in the local vicinity of said femto base station; and controlling uplink transmission timing of devices communicating with said femto base station to synchronize arrival times at said femto base station of signals, transmitted by said devices communicating with said femto base station to said femto base station uplink reference time.