Long-Range Acoustic Communication Using Differential Chirp Spread Spectrum

Design of a High Range, High Efficiency Spread Spectrum Transmitter for Audio Communication Applications

This work proposes a direct sequence spread spectrum transmitter with high transmission range and efficiency for audio signals. It is shown that by choosing high process gain for spread spectrum signal the data could reach a range of 55km in the 2.4GHz ISM band. By employing a light modulation scheme, we have a relaxed SNR requirement for having a low bit error rate (BER) which translates to re...

Acquisition of Direct Sequence Spread Spectrum Acoustic Communication Signals

Acquisition of the code timing in DS/SS systems is addressed for time-varying frequency-selective underwater acoustic channels. Acquisition algorithm based on adaptive channel estimation and fitlering is proposed. The algorithm employs feedback of pre-cursor and post-cursor inter-chip interference to provide a channel estimate from which the code timing is acquired. The channel estimate is also...

Precise Location Technology Based on Chirp Spread Spectrum

This article introduces chirp spread spectrum technology (CSS for short) and optimized location algorithm. Symmetric double-sided two way ranging technique (SDS– TWR for short) is applied to improve accuracy and range of measurement. Linear frequency modulation ranging technology utilizes protocols combining CSMA / CA and TDMA, and adjusts dynamically transmission rate and frame length accordin...

A Novel Chirp Modulation Spread Spectrum Technique for Multiple Access

This paper proposes a new approach in chirp modulation spread spectrum (CMSS). A good selection of the parameters of the linear chirps, which are used in chirp modulation, combined with antipodal signaling significantly reduces the multiple access interference (MAI) even for small time-bandwidth products. This makes such systems attractive for efficient spread spectrum multiple access. Equal en...

Characterization of Long-Range Time-Varying Underwater Acoustic Communication Channels