Patent ID: 6049534
Filing Date: 2000-04-11
Classification: H04B,H04W

Abstract:
A communication system, for carrying out hand-over from a radio base station to another radio base station in accordance with a request of hand-over output from the radio base station due to movement of a mobile station, said communication system comprising:a plurality of interface circuits through which communication signals are transmitted between a mobile station and a plurality of radio base stations via transmission paths;a switch which assigns the communication signals to said interface circuits such that the communication signals from said interface circuits are distributed in accordance with header information which the respective communication signals are transmitted from the radio base stations to the mobile station via the transmission paths;a control unit, connected to both said interface circuits and said switch, which receives a hand-over instruction output from the radio base station in accordance with the movement of the mobile station from the associated interface circuit; anda diversity hand-over processing unit, connected to both said control unit and said switch, which receives both a first communication signal received from the radio base station as a source of hand-over outputting a hand-over instruction and a second communication signal received from the radio base station as a destination of hand-over, and in accordance with the hand-over instruction to output one of the first and second communication signals to the associated interface circuit, transmits the communication signal received from the mobile station on the reception side for communication via the radio base station to both the interface circuit associated with the radio base station as the source of hand-over and the interface circuit associated with the radio base station as the destination of hand-over,wherein said diversity hand-over processing unit comprises:an instruction processing unit operated in accordance with an instruction output from said control unit,a synchronous selection unit which receives, via said switch, when a service area is changed from the radio base station as the source of hand-over to the radio base station as the destination of hand-over, both the communication signal from the interface circuit associated with the transmission path extending to the radio base station as the source of hand-over and the communication signal from another interface circuit associated with the transmission path extending to the radio base station as the destination of hand-over, in accordance with an instruction output from said instruction processing unit, and synchronizes both the two communication signals with each other, and outputs one of the two communication signals which is more excellent in quality to the interface circuit associated with the radio base station which communicates with the mobile station on the reception side for communication, anda signal duplicating unit which receives a communication signal from the interface circuit associated with the transmission path extending to the radio base station which communicates with the mobile station on the reception side for communication via said switch, transmits the communication signal thus received to both the interface circuit associated with the radio base station as the source of hand-over and the interface circuit associated with the radio base station as the destination of hand-over, and transmits the communication signal from the interface circuit associated with the radio base station which communicates with the mobile station on the reception side for communication to the radio base station as the destination of hand-over through that interface circuit.