Patent ID: 7899430

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 employing a code division multiple access method and including a transmitter for transmitting a first frame comprising a predetermined number of slots and having a first frame-length (L 1 ), 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 for receiving the frame transmitted by the transmitter; and the second communication system for transmitting a second frame having a second frame-length (L 2 ), employing a GSM method 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 substeps of setting a plurality of idle periods within the first transmission period by compressing a plurality of the first frames within the first transmission period, determining an idle period interval, the idle period interval being expressed by a number of slots and defined as an interval between corresponding portions in an idle period and in one of other idle periods, such that the idle period interval corresponds to an odd-number times of a value obtained by dividing the second frame-length (L 2 ) by a predetermined even 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; wherein one of the compressed first frames is divided into a first portion and a second portion, the first portion including a front edge of the frame timing and the second portion including a rear edge of the frame timing.