School of Physics and Physical Engineering, Qufu Normal University, Qufu 273165, China.
College of Underwater Acoustic Engineering, Harbin Engineering University, Harbin 150001, China.
Sensors (Basel). 2020 Jan 9;20(2):379. doi: 10.3390/s20020379.
Underwater acoustic (UWA) sensor networks demand high-rate communications with high reliability between sensor nodes for massive data transmission. Filtered multitone (FMT) is an attractive multicarrier technique used in high-rate UWA communications, and can obviously shorten the span of intersymbol interference (ISI) with high spectral efficiency and low frequency offset sensitivity by dividing the communication band into several separated wide sub-bands without guard bands. The joint receive diversity and adaptive equalization scheme is often used as a general ISI suppression technique in FMT-UWA communications, but large receive array for high diversity gain has an adverse effect on the miniaturization of UWA sensor nodes. A time-reversal space-time block coding (TR-STBC) technique specially designed for frequency-selective fading channels can replace receive diversity with transmit diversity for high diversity gain, and therefore is helpful for ISI suppression with simple receive configuration. Moreover, the spatio-temporal matched filtering (MF) in TR-STBC decoding can mitigate ISI obviously, and therefore is of benefit to lessen the complexion of adaptive equalization for post-processing. In this paper, joint TR-STBC and adaptive equalization FMT-UWA communication method is proposed based on the merit of TR-STBC. The proposed method is analyzed in theory, and its performance is assessed using simulation analysis and real experimental data collected from an indoor pool communication trial. The validity of the proposed method is proved through comparing the proposed method with the joint single-input-single-output (SISO) and adaptive equalization method and the joint single-input-multiple-output (SIMO) and adaptive equalization method. The results show that the proposed method can achieve better communication performance than the joint SISO and adaptive equalization method, and can achieve similar performance with more simpler receive configuration as the joint SIMO and adaptive equalization method.
水下声（UWA）传感器网络需要在传感器节点之间实现高速率、高可靠性的通信，以便进行大规模数据传输。滤波多音（FMT）是一种在高速 UWA 通信中使用的有吸引力的多载波技术，通过将通信频段划分为几个没有保护带的分离宽子带，可以明显缩短符号间干扰（ISI）的间隔，具有较高的频谱效率和较低的频率偏移灵敏度。联合接收分集和自适应均衡方案通常用作 FMT-UWA 通信中的一般 ISI 抑制技术，但为了获得高分集增益，大型接收阵对 UWA 传感器节点的小型化有不利影响。一种专门为频率选择性衰落信道设计的时反空时分组编码（TR-STBC）技术可以用发射分集代替接收分集来获得高分集增益，因此有助于采用简单的接收配置来抑制 ISI。此外，TR-STBC 解码中的空时匹配滤波（MF）可以明显减轻 ISI，因此有利于减少自适应均衡的后处理复杂度。在本文中，基于 TR-STBC 的优点，提出了一种联合 TR-STBC 和自适应均衡的 FMT-UWA 通信方法。该方法从理论上进行了分析，并通过仿真分析和从室内水池通信试验中收集的实际实验数据进行了性能评估。通过将该方法与联合单输入单输出（SISO）和自适应均衡方法以及联合单输入多输出（SIMO）和自适应均衡方法进行比较，验证了该方法的有效性。结果表明，该方法可以比联合 SISO 和自适应均衡方法实现更好的通信性能，并且可以实现与联合 SIMO 和自适应均衡方法类似的性能，而接收配置更为简单。
