Due to the high cost and safety risk brought about by wire penetration within the aerospace and underwater structure, reliable wireless cross-space multiple access transmission techniques become highly necessary. Lamb waves data transmission is recognized as a feasible solution, since it utilizes the solid structures as the transmission medium without being affected by electromagnetic radiation. However, in the case of synchronous transmission of multiple users, the aggravation of inter-access interference would severely weaken the reliability of the transmission system. Focusing on the issue of anti-interference synchronous independent data transmission for multiple cross-space users, this study proposes a Lamb waves-based pulse code frequency division multiple access (PCF-DMA) scheme. Firstly, a fast pulse position modulation strategy is established to improve the transmission rate. Considering the characteristics of the Lamb waves excitation pulses as the codeword, a PCF-DMA multiple access encoding method is designed. Secondly, by sparsely representing the Lamb waves physical transmission channel, a shift-invariant sparse deconvolution technology is proposed for decoding. Specially, to achieve reliable multiple access transmission with the PCF-DMA scheme, a normalized cross-correlation coefficient is used as the design criterion of the Lamb wave pulses. To validate these concepts, a three-user PCF-DMA data transmission system based on Lamb waves is built. The experimental results illustrate that the proposed design criterion can accurately predict the reliability of the multiple access transmission system. The bit error rate (BER) of the proposed PCF-DMA scheme is 30 % lower than that of conventional FDMA within a signal-to-noise ratio of −12 to 8 dB. Further, the influence factor analysis for the BER and communication rate are conducted. Finally, a synchronous independent data transmission for multiple cross-space users is achieved, with a maximum communication rate of 92.9 kbps per user and a BER below 0.17 %.

中文翻译：

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基于兰姆波的PCF-DMA：一种跨空间多用户抗干扰同步独立数据传输方案

由于电线穿透航空航天和水下结构带来的高成本和安全风险，可靠的无线跨空间多址传输技术变得非常必要。兰姆波数据传输被认为是一种可行的解决方案，因为它利用固体结构作为传输介质而不受电磁辐射的影响。然而，在多用户同步传输的情况下，接入间干扰的加剧会严重削弱传输系统的可靠性。针对多个跨空间用户的抗干扰同步独立数据传输问题，提出一种基于兰姆波的脉冲码频分多址(PCF-DMA)方案。首先，建立快速脉冲位置调制策略以提高传输速率。考虑兰姆波激励脉冲作为码字的特点，设计了PCF-DMA多址编码方法。其次，通过稀疏表示兰姆波物理传输信道，提出了一种平移不变稀疏反卷积技术进行解码。特别地，为了利用PCF-DMA方案实现可靠的多址传输，使用归一化互相关系数作为兰姆波脉冲的设计准则。为了验证这些概念，建立了基于兰姆波的三用户PCF-DMA数据传输系统。实验结果表明，所提出的设计准则能够准确预测多址传输系统的可靠性。所提出的 PCF-DMA 方案的误码率 (BER) 比传统 FDMA 的误码率 (BER) 低 30%，信噪比为 -12 至 8 dB。进一步对误码率和通信速率进行影响因素分析。最终实现了多个跨空间用户的同步独立数据传输，每个用户的最大通信速率为92.9 kbps，误码率低于0.17%。