TRANSMISSION DEVICE, RECEPTION DEVICE, TRANSMISSION METHOD AND RECEPTION METHOD

PROBLEM TO BE SOLVED: To provide a method, not necessitating rigid shield materials for an increased number of systems if the number of corresponding radio communication systems increases, without producing a cost increase of communication devices.SOLUTION: A transmission device, which transmits a plurality of high frequency signals having mutually different carrier frequencies, multiplies a plurality of low frequency signals respectively by a plurality of codes having mutually orthogonal relations (318), and adds up a plurality of low frequency signals multiplied by the plurality of codes by a first multiplier (317). The transmission device further converts the added low frequency signals into a plurality of high-frequency signals, and respectively multiplies them by the plurality of codes (315). By this, the codes respectively multiplied by the plurality of low frequency signals have orthogonal relations, and accordingly, the plurality of low frequency signals can be frequency converted in a unified manner, without producing mutual interference if the carrier frequencies become close by the plurality of high frequency signals.