Patent ID: 7912015

Claim:
A mobile radio communication method employed in a mobile radio communication system that comprises a first communication system employing a code division multiple access method including a transmitter for transmitting a first frame having a first frame-length (L 1 ), and for transmitting a 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 for receiving the frame transmitted by the transmitter; and a 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-multiple of the first transmission period, the second communication system coexisting with the first communication system, the mobile radio communication method including 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 a plurality of idle periods each having a half or less length of the first frame-length in the first transmission period; 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 corresponds to an odd-number multiple 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 frequency component of a control data transmission channel in the second communication system during the idle periods at the receiver in the first communication system.