Facilities of digital modulation techniques and conversion schemes in underground multiuser systems

The area of underground radio technology represents a constant problem among radio communication systems. This paper aims to suggest a possible scenario for transmission/receiving of signals from a salt mine. It is assumed that the system used is a synchronous CDMA system and the users´ signals have equal powers. In order for the performances to be improved the simulation includes digital modulation schemes such as QPSK and 16QAM and ADC levels. BER depends on the percentage of impurities in the salt, distance between transmitter and receiver and equipments used.