基于Chirp波形的物联信号在低轨卫星信道上的适应性分析

Adaptive Analysis of IoT Signals Based on Chirp Modulation in Low Earth Orbit Satellite Channels

以远距离无线电(Long Range Radio, LoRa)体制为代表的啁啾(Chirp)波形在低功耗广覆盖的物联网(Internet of Things, IoT)技术中具有广泛的应用。针对低地球轨道(Low Earth Orbit, LEO)卫星IoT(Satellite-based IoT,SIoT)场景下,Chirp波形在LEO高动态信道上的适应性问题,在传统LoRa体制的基础上提出了一种参数可配置和可扩展的物联波形设计方法,基于ZYNQ+AD9361的软件无线电(Software Defined Radio, SDR)平台,终端侧实现了带宽(Band Width, BW)、扩频因子(Spread Factor, SF)等参数可配置、可扩展的LoRa信号调制功能,网关侧实现了接收信号时频同步以及快速傅里叶变换(Fast Fourier Transform, FFT)解调算法。研究分析了LoRa调制的各项参数配置,在LEO卫星信道中的适应性;通过误比特率(Bit Error Ratio, BER)测试验证了LoRa调制的通信性能,并证明了参数可配置、可扩展的LoRa调制比传统LoRa调制,在LEO卫星信道下有更好的适应性。说明以LoRa体制为代表且基于Chirp波形的这一类物联信号在LEO SIoT场景下具有应用前景。

The widespread application of Chirp waveforms represented by the Long Range Radio(LoRa)protocol in low-power,wide-area Internet of Things(IoT)technologies is evident.Addressing the adaptability issues of Chirp waveforms in Low Earth Orbit(LEO)high-dynamic channels within LEO Satellite-based IoT(SIoT)scenarios,a parameter configurable and scalable IoT waveform design method is proposed based on the traditional LoRa system.Leveraging the ZYNQ+AD9361 Software Defined Radio(SDR)platform,we implemented configurable and scalable LoRa signal modulation functionalities at the terminal,encompassing parameters such as Band Width(BW)and Spread Factor(SF).On the gateway side,we realized time-frequency synchronization of received signals and Fast Fourier Transform(FFT)demodulation algorithms.Analysis of various parameter configurations of LoRa modulation in LEO satellite channels is conducted,followed by validation of communication performance through Bit Error Ratio(BER)testing.Results demonstrate that the parameter-scalable LoRa modulation introduced in this paper exhibits superior adaptability in LEO satellite channels compared to traditional LoRa modulation.This study underscores the prospective applications of LoRa-based IoT signals utilizing Chirp waveforms in the LEO SIoT networks.