RADIO COMMUNICATION SYSTEM

PROBLEM TO BE SOLVED: To provide the radio communication system which can back up a failure of a wired communication line at low cost by effectively utilizing an existing radio communication line. SOLUTION: When an abnormality signal Sa generated by a sensor 101 in case of abnormality on a transmitter side is transmitted to a modulation and false noise code addition unit 104 through a controller 102, a false noise code Sn is generated and put together with a connection signal Sd of the abnormality signal Sa and an object code Si to generate a sum signal Sx. At the same time, a radio transmitter 107 and a high-frequency switch 108 are controlled with control signals Ca and Cb and the sum signal Sx is sent out of an antenna 109. When this Sx is received on a receiver side, a signal processor 207 performs correlation calculation and on the basis of this result, Sn is subtracted from Sx to find the connection signal Sd.