Patent ID: 7995541

Claim:
A mobile radio communication system employing a CDMA method, comprising: a transmitter transmitting a plurality of uncompressed frames and a plurality of compressed frames within a first frame transmission period, which is formed of plural frames and required to transmit a predetermined number of frames; a receiver receiving said uncompressed frames and said compressed frames transmitted by said transmitter , said transmitter including an interleaver which performs interleaving of data in an uncompressed frame in bit units; a spreading unit, in which a plurality of uncompressed frames processed by said interleaver are inputted, wherein said spreading unit compresses uncompressed frames within said first frame transmission period to produce compressed frames, divides each of said compressed frames into two divided parts, allocates one of said divided parts at the beginning of a frame period and the other one of said divided parts at the end of said frame period, and creates, into each of said compressed frames, an idle period; and a radio frequency transmitter which transmits said compressed frames processed by said spreading unit, and said receiver including a radio frequency receiver which monitors, within said idle period, a frequency component in a control channel, said control channel having a second frame transmission period and being employed in a different mobile radio communication system, wherein the idle periods are set fixedly in the first transmission period by the transmitter.