Mobile communication system

摘要

There is a problem that when a closed subscriber group (CSG) cell available to subscribers is installed in a macro cell area, communication cannot be performed due to the interference between a macro cell and the CSG cell in an area thereof. The CSG cell that is provided in the CSG cell area and transmits a downlink synchronization signal using a radio frame assigns control signals to a first subframe and a second subframe among a plurality of subframes constituting the radio frame, and the macro cell that is provided in the macro cell area and transmits a downlink synchronization signal using the radio frame assigns control signals to a third subframe and a fourth subframe, which are shifted from the first subframe and the second subframe by a predetermined number of subframes, respectively, among the plurality of subframes constituting the radio wave, the CSG cell and the macro cell being configured to perform transmission in synchronization with each other.

主权项

1. A mobile communication system comprising plural user equipments, a first base station and a second base station, the user equipments performing data transmission/reception using an orthogonal frequency division multiplexing (OFDM) system as a downlink access system and a single career frequency division multiple access (SC-FDMA) system as an uplink access system, the first base station being provided to a first cell made open only to specific ones of said user equipments and being configured to transmit, to said user equipments, control signals including a downlink synchronization signal using a radio frame including a predetermined number of subframes, the second base station being provided to a second cell made available for non-specific ones of said user equipments and being configured to transmit, to said user equipments, control signals including a downlink synchronization signal using a radio frame including the same number of subframes as those of said radio frame used in transmission by said first base station, wherein:
said first base station assigns said control signals to a first subframe and a second subframe among a plurality of subframes constituting said radio frame; said second base station assigns said control signals to a third subframe and a fourth subframe among the plurality of subframes constituting said radio frame, the third subframe and the fourth subframe being disposed in frame slots that are shifted in time from frame slots in which said first subframe and said second subframe are disposed, frame slots of the first base station aligning with frame slots of the second base station; and said first base station and said second base station transmit said control signals in synchronization.