基于模拟扩频信号处理的超低功耗LoRa唤醒机制  

Ultra-low Power LoRa Wake-up Mechanism Based on Analog Spread Spectrum Signal Processing

作　　者：冯陆崴 朱丰源 田晓华[1] FENG Luwei;ZHU Fengyuan;TIAN Xiaohua(Department of Electronic Engineering,School of Electronic Information and Electrical Engineering,Shanghai Jiao Tong University,Shanghai 200240,China)

机构地区：[1]上海交通大学电子信息与电气工程学院电子工程系,上海200240

出　　处：《信号处理》2023年第6期1079-1088,共10页Journal of Signal Processing

基　　金：国家重点研发项目(2020YFB1708700);国家自然科学基金项目(61922055,61872233,61829201,61532012,61325012,61428205)。

摘　　要：在基于LoRa(Long Range Radio)的大规模物联网系统中,为了在低功耗的前提下降低通信延迟,同时与LoRa系统的通信距离相近,提出一种基于低功耗下变频和模拟解扩频机制的LoRa唤醒接收机制。首先利用发射机发出一个标准的LoRa前导码序列和一个与其中心频率有一定频率差的单音载波。其次在接收端天线对前导码序列和载波同时接收后,利用肖特基二极管的非线性效应,使两个信号完成混频,即单音载波充当本振信号并实现LoRa信号的下变频。然后控制射频开关的通断时序完成对接收信号的解扩频。最后对解调信号进行基带处理,利用两路正交信号降低误码率。理论分析和仿真结果表明,本文提出的基于模拟扩频信号处理的超低功耗唤醒机制在LoRa系统中具有可行性,接收灵敏度最高达到-136 dBm且整体功耗仅为137μW。In a large-scale IoT system based on LoRa(Long Range Radio),in order to reduce the communication delay with low power consumption while being close to the communication distance of the LoRa system,a LoRa wake-up mechanism based on low-power down-conversion and an analog dechirp mechanism is proposed.Firstly,a standard LoRa preamble sequence and a single-tone carrier with a certain frequency are sent out using the transmitter.Secondly,after the antenna of the receiver receives both the preamble sequence and the carrier wave,the non-linear effect of the Schottky diode is used to complete the mixing of the two signals,i.e.,the single-tone carrier wave acts as the local oscillation signal and achieves the down-conversion of the LoRa signal.Then the on/off timing of the RF switch is controlled to complete the demodulation of the received signal.Finally,baseband processing is performed on the demodulated signal to reduce the SER(Symbol Error Rate)using two quadrature signals.Theoretical analysis and simulation results show that the ultra-low power wake-up mechanism based on analog spread spectrum signal processing proposed in this paper is feasible in LoRa systems,with a reception sensitivity of-136 dBm and an overall power consumption of only 137μW.

关 键 词：超低功耗 LoRa 模拟解扩频 唤醒机制 

分 类 号：TN92[电子电信—通信与信息系统]