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This paper presents an underwater acoustic communication channel model to reveal the influence of rough bottom reflection and scattering on the channel. We analyze experimental data from two channel measurement campaigns, and concentrate on the channel properties such as the spread-Doppler function, the time coherence function and the spatial coherence function to study the variations induced by medium...
The underwater acoustic communication system has a number of restrictions to DSP core because of the bad underwater environment. In view of this situation, we have designed a DSP platform with high performance, small scale, low power consumption and high reliability. This platform has only one processer, and a high speed and volume, low power SDRAM is integrated to improve the computation ability...
Underwater acoustic network nodes are widely used in underwater sensor networks. In this paper, an underwater acoustic network nodes that works at the frequency between 10 kHz and 15 kHz is designed. This system can operate in two modulation methods, MFSK and QPSK, which have a data rate of 288 bps and 4.2 kbps respectively. Two series of experiments were conducted in different seasons to verify the...
A direct-adaption based bidirectional turbo equalizer (DA-BTEQ) is proposed for multiple-input multiple output (MIMO) underwater acoustic (UWA) communications. Abandoning the traditional channel estimation process, the proposed DA-BTEQ works in a direct-adaption mode and is implemented with bidirectional soft-decision feedback equalizer (SDFE) to suppress error propagation. The diversity gain is exploited...
In-band full duplex (IBFD) can theoretically double the throughput of communication systems, and its feasibility has been demonstrated in wireless radio design. It is a promising alternative for the severely bandwidth-limited underwater communication system since it exploits both the temporal and spectral efficiency to the most. Self-interference cancelation is the primary challenge in IBFD's implementation...
This work considers the problem of false frame synchronization for underwater acoustic communication (UWAC), and a new frame synchronization approach based on Linear Frequency Modulation (LFM) signal parameters estimation is proposed. Two parameters estimation techniques including Fractional Fourier Transform (FRFT) estimation and Maximum Likelihood (ML) estimation have been presented in this paper...
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