# Generalized Frequency Division Multiplexing-Based Low-Power Underwater Acoustic Image Transceiver
###### Abstract  
In this paper, a low-power underwater acoustic (UWA) image transceiver based on generalized frequency division multiplexing (GFDM) modulation for underwater communication is proposed. The proposed transceiver integrates a low-density parity-check code error protection scheme, adaptive 4-quadrature amplitude modulation (QAM) and 16-QAM strategies, GFDM modulation, and a power assignment mechanism in an UWA image communication environment. The transmission bit error rates (BERs), the peak signal-to-noise ratios (PSNRs) of the received underwater images, and the power-saving ratio (PSR) of the proposed transceiver obtained using 4-QAM and 16-QAM, with perfect channel estimation, and channel estimation errors (CEEs) of 5%, 10%, and 20% were simulated. The PSNR of the received underwater image is 44.46 dB when using 4-QAM with a CEE of 10%. In contrast, PSNR is 48.79 dB when using 16-QAM with a CEE of 10%. When BER is \(10^{-4}\), the received UW images have high PSNR values and high resolutions, indicating that the proposed transceiver is suitable for underwater image sensor signal transmission. GFDM; low-power; image transceiver; BER; simulation of transmission 20222223133052022223130520222231305202222231305202222223130520  
different assumptions for a more comprehensive result, e.g., via the design and adjustment of different parameters (e.g., transmission power). [PERSON] et al. [5] simulated the communication performance of the UWA channel capacity parameter in an UWA sensor network. However, data communication in underwater environments is difficult due to time-varying channel parameters. An accurate simulation approach is required to replicate the behavior of UWA sensor networks in a real scenario, and improve the transmission performance of UWA sensor networks. [PERSON] et al. [6] proposed an adaptive robust channel estimation mechanism for highly time-varying UWA communication channels with multipath propagation, large delay spreads, and frequency-dependent transmission loss. Adaptive filtering techniques, with a minimization logarithmic cost function, increased the convergence rate of the channel estimators. Orthogonal frequency division multiplexing (OFDM)-based UWA communication transmission solutions can combat the effects of long and time-varying channel impulse responses in an underwater environment. The bandwidth efficiency, reliability, latency, transmission throughput, and changing underwater propagation channel are critical parameters for UWA communication system implementation. Emerging UWA sensor network applications rely on physical layer technology due to its high throughput, reliability, and energy efficiency. [PERSON] et al. [7] aimed to explore new directions for next-generation underwater acoustic modems. Simulation methods are necessary to explore the design aspects of underwater acoustic communication, and the sea experimentation cost can be reduced. [PERSON] et al. [8] focused on the physical fundamentals and engineering implementations for efficient data transmission via mobile communication using physical waves in UWA sensor networks. Acoustic waves are the most widely used waves, due to the low signal attenuation of sound in water. The challenges of the UWA communication system include long latency, low bandwidth and high time-varying channel characteristics. MATS 3G has been used in underwater communications for decades, with impressive antenna sizes at the transmitters and loop antennas at the receivers [9]. [PERSON] et al. [10] adopted the downlink power allocation strategy using an OFDM technique for UWA communication networks. The block error rates with different signal-to-noise ratio (SNR) values were presented, and throughput performances for with and without power assignments (PAs) were compared. [PERSON] et al. [11] proposed a power allocation technology for non-orthogonal multiple access (NOMA) in UWA sensor networks.