Experimental Evaluation Results of Acoustic Spread Spectrum Communications Employing Orthogonal Gold Sequences

This paper proposes code division multiple access (CDMA) acoustic spread spectrum communications for uplink terrestrial acoustic communications. For CDMA, the multiple access performance strongly depends on the auto/cross-correlation of the spreading codes. Therefore, this paper discusses a spreading code search criterion based on the orthogonal Gold sequences, which can select a set of spreading codes with good auto/cross-correlation at small computational complexity. Next, this paper proposes a frame structure, synchronization schemes, and frequency response of band-pass filters to cope with acoustic ambient noises, for the proposed acoustic spread spectrum communications. Finally, field evaluation results confirm that the proposed acoustic spread spectrum communications have good performance thanks to the proposed band-pass filter.