高能效多载波水声通信技术研究

The underwater acoustic(UWA) channel has large delay and limited bandwidth, which leads to the high error rate and low communication rate. Recently, two main research fields of UWA communication are short-range high-speed UWA communication and low-speed remote UWA communication. Among them, the multi-carrier modulation technology in short-range high-speed UWA communication has attracted wide attention due to the advantage of high spectrum utilization. However, the high peak-to-average ratio(PAPR) caused by the large number of carriers affects the energy utilization of the system and is an obstacle to its application. This research intends to solve this problem from two aspects. On the one hand, researching on the PAPR reducing algorithm of traditional multi-carrier technology-orthogonal frequency division multiplexing(OFDM) to improve the system’s energy efficiency. On the other hand, an emerging 5G multi-carrier technology- generalized frequency division multiplexing technology(GFDM), which has low PAPR and high spectrum utilization is introduced into the UWA communication field. GFDM can freely choose the number of subcarriers and the number of subblocks, which is a new direction for the development of UWA communication. In order to achieve robust communication in a complex underwater acoustic environment, two technologies are proposed to be combined with adaptive techniques. This research applies this technology to the UWA communication for the first time.The research results can not only improve the energy utilization rate and spectrum utilization rate of multi-carrier UWA communication system, but also promote the realization of UWA communication networking, which has high reference value for the future UWA network and the UWA communication technology.

水声信道传播时延大、带宽受限，导致了水声通信误码率高，通信速率低。多载波调制技术以高频谱利用率的优势，在带宽资源有限的高速水声通信中受到了广泛关注。但载波数目多导致的高峰均比，影响了系统的能量效率。本课题针对这一问题，一方面，研究适用于OFDM水声领域的降峰均比算法，实现高速、高能效的水声通信系统。另一方面，针对无线电5G中峰均比低、频谱利用率高的基于滤波器组的广义频分复用技术展开研究，并提出利用扩频技术解决其对信道敏感的弱点。最后，为适应信道环境的变化，充分利用信道资源，拟将两种峰均比较低的多载波调制技术结合，实现一种高能效自适应多载波水声通信系统。本课题首次将可自由选择子载波数目、子块数目的方案应用到水声通信领域中，研究成果可提高多载波水声通信系统的能量利用率和频谱利用率，推进水声通信组网技术的实现，具有很好的推广和应用价值。

本项目针对“水声多载波通信系统能量效率提升研究”专题确定的研究目标，对传统降低峰均比算法进行优化，并将GFDM技术应用在水声多载波通信系统中，提升水下多载波通信性能，促进水声多载波技术的发展。.首先针对多载波水声通信中的OFDM技术峰均比高的问题，分析限幅类算法及压扩变换算法的效果，提出改进压扩变换与限幅结合算法，能够在实现降低峰均比的同时，对OFDM水声通信系统误码性能影响最小。在降低峰均比的概率类技术方面研究基于混沌序列的PTS优化算法，有效降低算法复杂度的同时减小系统的边带信息传输具有更好的降低峰均比能力。.然后从无线电5G新兴多载波技术入手，深入研究了基于GFDM技术的通信系统，包括通信系统框图、调制器结构及滤波器组参数及GFDM系统峰均比等问题。提出了将扩频方法引入到多载波GFDM调制技术中，实现了GFDM-DS水声通信系统。为了提高通信系统保密性、增加扩频序列的可选择性和接收端同步的准确程度，将混沌序列引入GFDM扩频中，利用混沌序列的自相关性强的优点，实现了GFDM-CSSS水声通信系统。.通过具体的计算机仿真及相应实验验证，上述方法能够很好的提升水声多载波通信系统能量效率，提升水下多载波通信性能，促进水声多载波技术的发展。