To obtain such a solution with which IS-95 technology is compatible with the existing IS-95 infrastructure by combining modulated signals comprising entire information of data streams to send as a multi band signal.

Encoded data streams which are generated by a broadband signal generator 302 related to each broadband data stream are modulated and spread over the same number M carrier frequencies which are used by M IS-95 signal generators 102. A broadband signal is encoded by using a QPSK function that is designed that a broadband signal related to each data stream crosses both a broadband signal related to the rest of broadband data streams and a narrowband signal related with all IS-95 users at right angles, so that a broadband signal may not interfere with a narrowband IS-95 signal. A QPSK spectrum spread modulation system of each broadband unit 303 insures the orthogonality.