This article introduces a highly integrated passive wireless sensing system based on the extended electronic product code (EPC) Gen2 protocol, using sensor tags and a reader to support concurrent data streams from multiple sensors. Multiple subcarrier multiple access (MSMA) is used by assigning different subcarrier frequencies to the sensor tags for backscattering so that each tag has an independent channel for communication to achieve the simultaneous streaming of multisensor data. In order to improve the subcarrier frequency accuracy and further increase the number of communication channels, this article proposes a novel method of subcarrier frequency calibration based on the Gen2 protocol. This method enables a high-accuracy clock to be generated on-chip. At the same time, this article also proposes a method based on Gen2 protocol to start a group of tags and receive real-time data in parallel. The tag chip is fabricated in a $0.18{-}\mu \text{m}$ CMOS process with a die size of $850\,\,\mu \text{m}\,\,\times 850\,\,\mu \text{m}$ , and the reader prototype is built using software-defined radio equipment. The test results show that the sensing system proposed in this article can collect and recognize concurrent data streams from multiple sensor tags synchronously. The measured sensitivity of the sensor tag is −14.9 dBm with a 3-axis accelerating sensor, and the calibration accuracy of subcarrier frequency is better than ${\pm }{\mathrm {0.385}}$ kHz in the range of 40–640 kHz. With this accuracy, the tags can be allocated up to 78 subcarrier communication channels theoretically.

中文翻译：

---

具有多个标签同步数据流的高度集成无源无线传感系统

本文介绍了一种基于扩展电子产品代码 (EPC) Gen2 协议的高度集成无源无线传感系统，该系统使用传感器标签和阅读器来支持来自多个传感器的并发数据流。多子载波多址（MSMA）是通过为传感器标签分配不同的子载波频率进行反向散射，使每个标签具有独立的通信通道，以实现多传感器数据的同时流传输。为提高子载频精度，进一步增加通信通道数，本文提出了一种基于Gen2协议的子载频校准新方法。这种方法能够在芯片上生成高精度时钟。同时，本文还提出了一种基于Gen2协议启动一组标签并并行接收实时数据的方法。标签芯片是在一个制造 $0.18{-}\mu \text{m}$CMOS工艺，裸片尺寸为 $850\,\,\mu \text{m}\,\,\times 850\,\,\mu \text{m}$ ，并且阅读器原型是使用软件定义的无线电设备构建的。测试结果表明，本文提出的传感系统可以同时采集和识别来自多个传感器标签的并发数据流。传感器标签的实测灵敏度为-14.9 dBm，采用3轴加速传感器，副载波频率校准精度优于 ${\pm }{\mathrm {0.385}}$kHz 在 40–640 kHz 的范围内。有了这个精度，理论上标签最多可以分配78个子载波通信信道。