Patent ID: 7593370

Claim:
A mobile radio communication method employed in a mobile radio communication system, the mobile communication system including a first and second communication system, the first communication system configured to employ a code division multiple access method, the first communication system including a transmitter configured to interleave data in bit units within a first frame comprising a predetermined number of slots and having a first frame-length (L 1 ), and configured to transmit the first frame, at a first transmission period which is defined as a period required to transmit a first specified number of the first frames, and a receiver configured to receive the frame transmitted by the transmitter, and the second communication system is configured to transmit a second frame having a second frame-length (L 2 ), where the second frame is transmitted at a second transmission period which is defined as a period required to transmit a second specified number of the second frames and not an integer-times of the first transmission period, the second communication system coexisting with the first communication system, the mobile radio communication method comprising the steps of: transmitting the first frame from the transmitter in the first communication system to the receiver in the first communication system, the transmitting step including setting P pieces of idle periods within the first transmission period, where P is an even number, determining an idle-period interval, defined as an interval between corresponding portions in an idle period and in one of other idle periods, such that the idle-period interval most approximates to a value of (L 2 /P) times (P′n+1), where n is a natural number, and transmitting the first frames including the idle periods which are placed at the determined idle-period interval to the receiver in the first communication system; and observing a control data transmission channel in the second communication system during the idle periods at the receiver in the first communication system.