Acta Photonica Sinica, Volume. 51, Issue 10, 1006006(2022)
Performance of OQPSK Modulation System Based on Composite Seawater Channel
Considering the competition for oceanic resources among different nations, Underwater Wireless Communication (UWC) technology has a lot of potential for development. As compared to its traditional counterparts, namely underwater acoustic communication and radio frequency communication, Underwater Wireless Optical Communication (UWOC) has many advantages, such as a strong information-carrying capacity, a faster communication rate, and good confidentiality, which can better suit the practical communication requirements of high-speed and large-capacity, lower implementation costs, and lower time latency in underwater wireless communication. The effects of the UWOC channel on the received laser pulse are typically categorized into the signal power attenuation caused by absorption, scattering, and the light intensity scintillation caused by oceanic turbulence, which leads to a decline in the transmission performance (bit error rate) of the UWOC system. The most widely used turbulence channel models are only suitable for a specific turbulence state. In order to further analyze the signal characteristics and system performance of the UWOC system of the Offset Quadrature Phase Shift Keying (OQPSK) modulation under the common action of turbulence channel and attenuation channel, this paper uses the Exponential Generalized Gamma (EGG) turbulence distribution model, which is more consistent with real oceanic channel characteristics. We obtain the turbulent random noises utilizing the acceptance-rejection sampling algorithm and further establish a composite channel model taking into account the attenuation channel, turbulence channel, and the Additive White Gaussian Noise (AWGN). In addition, according to the waveform of simulating signal, varying turbulence noise parameters, system noise parameters, and attenuation channel parameters, we analyze the average Bit Error Rate (BER) characteristics of the OQPSK modulation in the UWOC system. The simulation results show that the signal waveform does not change when it passes through the attenuation channel, but the amplitude is severely attenuated; the signal envelope passing through the turbulence channel changes with time, and the speed of signal amplitude change is negatively correlated with the turbulence coherence time; the signal waveform passing through the composite channel is distorted nonlinearly. For strong oceanic turbulence of the scintillation index
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Yi YANG, Jiayuan LEI, Xiaobo WANG, Fengtao HE, Yan LIU, Huan NIE. Performance of OQPSK Modulation System Based on Composite Seawater Channel[J]. Acta Photonica Sinica, 2022, 51(10): 1006006
Category: Fiber Optics and Optical Communications
Received: Aug. 8, 2022
Accepted: Oct. 8, 2022
Published Online: Nov. 30, 2022
The Author Email: YANG Yi (yangyi@xupt.edu.cn)