SIGNAL TRANSMITTING METHOD AND COMMUNICATION SYSTEM

摘要

Signals are transmitted in secret even when the information representing the destination terminal is opened because a common access channel is used. Obstruction can be well prevented. A random number bit adding section (6) adds a random number alpha (digital signal) generated by a random number generator (5) to the transmission data DA generated by a transmission data generator (1), and outputs the composite signal (DA, alpha ). An enciphering section (2) enciphers the signal (DA, alpha ) and outputs the ciphered signal (DA, alpha )'. A receiving device deciphers the ciphered signals (DA, alpha )' to the original signals (DA, alpha ) and reproduces the data DA by removing the random number bit alpha .