单载波频域均衡压电声透通信研究

Penetration-free ultrasonic data transmission using single-carrier frequency domain equalization

研究了单载波频域均衡压电声透通信技术,将系统复杂度集中至介质一侧,并实现高速压电声透通信。分析了压电声透系统信道特性,通过变步长自适应滤波器,有效降低了信道响应的计算量并提高了收敛速度。提出一种改进的单载波频域均衡相关同步算法,可涵盖已有的多种同步方案并提出最佳同步的帧结构判决方案。在此基础上,结合训练序列信息和能量判决方法,提出了针对压电声透通信系统的综合同步算法。同时针对实际应用中的采样起始点偏移和频率偏差累积问题,提出了相应的优化策略。实验中采用中心频率为500 kHz的换能器,在4 cm厚钢板两侧可达到1.298 Mbps的最大传输速率,表明该算法能有效抑制码间干扰,降低误比特率。

A penetration-free ultrasonic data transmission algorithm using Single-Carrier Frequency Domain Equaliza- tion （SC-FDE） is proposed. The main advantage of the algorithm is to concentrate most system complexity to one side of metal barrier. Characteristics of penetration-free ultrasonic data transmission channel are considered, the computational complexity can be reduced, while rate of convergence can be accelerated by a variable step-size adaptive algorithm. A correlation synchronization algorithm is presented, which can be treated as a generalization of several existing synchro- nization algorithms. Schemes of combining this revised correlation synchronization algorithm with energy detection and training sequence information are also analyzed. System performance degradation is caused by starting point bias as well as accumulated carrier frequency offset. Corresponding optimization strategy is presented. Monte Carlo results demonstrate the effectiveness of the proposed SC-FDE penetration-free ultrasonic data transmission algorithm. The full system is capable of transmitting data at 5.298 Mbps through a 4-cm thick steel wall using transducers resonance at 500 kHz. Both severe inter-symbol interferences as well as bit-error rate during high-speed data transmission can be reduced.