Transmission and Reception of Spread Spectrum Signals at Acoustic Frequencies

An algorithm of correlation reception of binary phase-shift keying pseudonoise signals generated by the direct sequence spread spectrum technique has been developed. The algorithm includes a procedure of synchronizing the transmitter and receiver based on detecting, using a matched filter, a separate signal obtained by manipulating the carrier with a pseudorandom sequence. To determine information symbols, the receiver distinguishes phase-shift keyed signals formed in accordance with the direct or inverse m-sequence of 127 chips. The algorithm of detecting and distinguishing spread spectrum signals by correlation accumulation is implemented as a digital module for the GNU Radio toolkit. A semirealistic simulation of the communication system with spread spectrum signals in the 512 Hz audio range has been carried out. The results of the work can be used in hydroacoustic communication systems and the Underground Internet of Things.