This brief proposes half-duplex wireless networks that use acoustic guided waves traveling on or through structures for physically-secure long-range power and data telemetry. It also develops a protocol for such networks to optimize their power and data delivery to compensate for slowly-varying factors like temperature and structural damage. Specifically, near-maximum power point tracking (nMPPT) is implemented by searching for the optimal transmission frequency in complex acoustic channels. Binary frequency shift keying (BPSK) modulated on the power waveform is proposed for downlink. A power-efficient fast uplink is achieved by using Non Return to Zero - Inverted (NRZ-I) data encoding. Data security is naturally ensured by the unique channel responses defined by the transceivers’ physical locations. Miniature smart sensor nodes with a quiescent power of 4.8 $\mu \text{W}$ and a peak power of $\sim 200~\mu \text{W}$ have been developed for such sparse networks. The proposed half-duplex telemetry approach is experimentally evaluated on a structural health monitoring (SHM) test bed and achieves a power transfer of $\sim 181.8~\mu \text{W}$ at 0.5 m and a BER of 10⁻⁴ for a 80 bps downlink driven at 20 $\text{V}_{pp}$ , and a BER of 10⁻⁴ for a 2 Mbps uplink driven at $\sim 2~\text{V}_{pp}$ .

中文翻译：

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结构上的自优化无线网络

本简报提出了半双工无线网络，该网络使用在结构上或通过结构传播的声导波，以实现物理安全的远程电源和数据遥测。它还为此类网络开发了一种协议，以优化其功率和数据传输，以补偿温度和结构损坏等缓慢变化的因素。具体来说，近最大功率点跟踪 (nMPPT) 是通过在复杂的声学通道中搜索最佳传输频率来实现的。在功率波形上调制的二进制频移键控 (BPSK) 建议用于下行链路。通过使用不归零 - 反转 (NRZ-I) 数据编码实现了高效节能的快速上行链路。收发器的物理位置定义的唯一信道响应自然地确保了数据安全。 $\mu \text{W}$ 和峰值功率 $\sim 200~\mu \text{W}$ 已经为这种稀疏网络开发了。所提出的半双工遥测方法在结构健康监测 (SHM) 测试台上进行了实验评估，并实现了功率传输 $\sim 181.8~\mu \text{W}$ 在 0.5 m 和 10 ^-4的 BER对于以 20 驱动的 80 bps 下行链路 $\text{V}_{pp}$ ，以及 BER 为 10 ^-4的 2 Mbps 上行链路驱动 $\sim 2~\text{V}_{pp}$ .