PURPOSE: To obtain the CDMA communication system capable of making stable communication even in the presence of a CM disturbing wave by providing a specific modulation section and a specific demodulation section to the system.
CONSTITUTION: Data inputted at first from an input terminal 1 are subjected to DS modulation at a DS modulator 2 based on a code generated in a spread code generator 6. That is, only one wave subjected to hopping is lost against fixed CM noise by implementing frequency hopping and data are recovered by the conventional error correction method. On the other hand, the signal inputted from an input terminal 8 is subjected to frequency conversion at a mixer 9 and inputted to a DS demodulator 11. Since hopping pattern is implemented in the unit of data blocks, inverse spread is implemented by applying hopping to the receiver side based on the information obtained by demodulating the signal subjected to direct spread spectrum processing. Thus, the inverse spread synchronization circuit or frequency hopping is not required.
OKAMOTO TAKESHI
HIGASHIMOTO MASASHI
HIKOFUSA KEIJI
