Practical Multiple User System Using Heterogeneous Frequency Modulation for High Data Rate in Underwater Sensor Network

초록

The goal of this paper is to improve the data rate in a multiple user (MU) underwater system. Toward this goal, we propose a new modulation, a combination of hyperbolic frequency modulation (HFM) and power frequency modulation (PFM) signals. By overlapping the heterogeneous signals, the number of bits which can be transferred during a symbol duration increase. In addition, by finely dividing the bandwidth into sub-channels, we increase the size of available modulation order per each user. Owing to the Doppler invariant characteristic of HFM signal, the Doppler shift can be estimated and it is utilized to compensate for the Doppler distortion occurred at the PFM signal. To take acoustic channel properties into account the system evaluation, we develop an acoustic network simulator involving well-defined propagation physics. The simulation results substantiate that our modulation scheme significantly increases data rate as compared with the existing MU systems.

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