基于LoRa的卫星物联网系统接收机同步与非相干软解调方案

doi:10.12263/DZXB.20220118

电子学报

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基于LoRa的卫星物联网系统接收机同步与非相干软解调方案

余忠洋¹^,², 高继勋¹(), 郭小波¹(), 李博¹(), 何栎¹(), 黄治国¹()

^1.河南工程学院计算机学院、河南省智慧城市多模态智能交互系统工程研究中心, 河南郑州 451191
^2.西安电子科技大学综合业务网理论及关键技术国家重点实验室, 陕西西安 710071

收稿日期:2022-01-25 修回日期:2022-06-16 出版日期:2022-07-13
- 作者简介:
- 余忠洋　男， 1989年8月出生于安徽省六安市.现为河南工程学院讲师.主要研究方向为短突发通信、卫星通信和物联网通信领域的物理层组帧技术和接收机同步技术等.E-mail: xd_yzy2013@sina.com
  高继勋　男， 1980年5月出生于河南省洛阳市.现为河南工程学院副教授.主要研究方向为嵌入式技术、人工智能、图像识别技术.E-mail: gaojixun@haue.edu.cn
  郭小波　男， 1980年4月出生于河南省新安市.现为河南工程学院副教授.主要研究方向为智能传感网技术、并行计算.E-mail: gxb@haue.edu.cn
  李　博　男， 1982年8月出生于河南省郑州市.现为河南工程学院讲师.主要研究方向为研究方向为计算机视觉、数据处理与分析.E-mail: csslib@haue.edu.cn
  何　栎　男， 1982年3月出生于江西省萍乡市.现为河南工程学院讲师.主要研究方向为进化计算与物联网.E-mail: engineerheli@126.com
  黄治国　男， 1978年11月出生于湖南省临湘市.现为河南工程学院副教授.主要研究方向为数据挖掘、智能计算.E-mail: huangzg2020@139.com
- 基金资助:
- 河南省科技攻关计划项目 (222102210200); 河南省高等学校重点科研项目 (22A520011)

Receiver Synchronization and Nonconherent Soft Demodulation Scheme for LoRa-Based Satellite IoT Systems

YU Zhong-yang¹^,², GAO Ji-xun¹(), GUO Xiao-bo¹(), LI Bo¹(), HE Li¹(), HUANG Zhi-guo¹()

^1.Henan Provincial Smart City Multimodal Intelligent Interactive System Engineering Research Center，School of Computer Science，Henan University of Engineering，Zhengzhou，Henan 451191，China
^2.State Key Laboratory of Integrated Services Networks，Xidian University，Xi’an，Shaanxi 710071，China

Received:2022-01-25 Revised:2022-06-16 Online:2022-07-13

摘要/Abstract

摘要：

LoRa（Long Range）技术是一种改进的高阶啁啾扩频（Chirp Spread Spectrum，CSS）调制技术，如今已经成为了地面物联网（Internet of Things，IoT）的主流调制技术之一.不同于地面物联网，卫星IoT将会实现全球范围内的无缝覆盖，但其通信距离遥远和高速移动使得接收机通常工作在极低信噪比下并面临较大时延和多普勒频移.鉴于此，本文将LoRa技术应用到卫星IoT系统中并研究相应的接收机同步与非相干软解调方案.首先给出了卫星IoT上行链路的系统模型和数据帧结构.接着根据LoRa信号的特点，设计了一种联合时延与多普勒频移估计方案.为了进一步消除相偏和其他残留项的影响以及考虑采用基于软判决译码的编码方案，又设计了一种低复杂度的非相干软解调算法.仿真结果表明基于所提同步方案和软解调算法的turbo-LoRa系统可以在极低信噪比和较小导频开销下获得接近于理想情况的误码性能，且在BER=10^-5下优于Hamming-LoRa系统3dB.

关键词: LoRa调制, 接收机同步, 非相干解调, 极低信噪比, 卫星物联网, 6G通信

Abstract:

LoRa(Long Range) technique is an improved high-order chirp spread spectrum(CSS) modulation technique, and becomes one of the mainstream modulation techniques for terrestrial internet of things(IoT). Different from the terrestrial IoT, satellite IoT can achieve seamless global coverage, however, the corresponding receiver often works under the extremely-low signal-to-noise ratio(SNR) and also faces large delay and Doppler shift due to long distance and high-speed movement. To this end, this paper applies the LoRa technique to satellite IoT systems and study the relevant receiver synchronization as well as noncoherent soft demodulation scheme. First, considered system model and data frame structure of the uplink satellite IoT are given. Then, according to the feature of LoRa signals, a joint delay and Doppler shift estimation scheme is proposed. In order to further eliminate the impact of the phase offset as well as other residual terms and consider using soft-decision decoding based coding schemes, a low-complexity noncoherent soft demodulation algorithm is also designed. Simulation results show that the turbo-LoRa system based on the proposed synchronization scheme and soft demodulation algorithm can achieve near ideal error performance under extremely low SNR and small pilot overhead, and can provide 3dB gains over the Hamming-LoRa system at a bit error rate(BER) of 10^-5.

Key words: LoRa modulation, receiver synchronization, nonconherent demodulation, extremely-low SNR, satellite IoT, 6G communications

中图分类号:

TN911.23

余忠洋, 高继勋, 郭小波, 李博, 何栎, 黄治国. 基于LoRa的卫星物联网系统接收机同步与非相干软解调方案[J]. 电子学报, DOI: 10.12263/DZXB.20220118.

YU Zhong-yang, GAO Ji-xun, GUO Xiao-bo, LI Bo, HE Li, HUANG Zhi-guo. Receiver Synchronization and Nonconherent Soft Demodulation Scheme for LoRa-Based Satellite IoT Systems[J]. Acta Electronica Sinica, DOI: 10.12263/DZXB.20220118.

图/表 6

图1 系统模型

图2 数据帧结构

图3 三种非相干软解调算法的误码性能

图4 不同残留联合偏移量下所提非相干软解调算法性能

图5 不同导频长度下所提同步方案的RMSE性能

图6 基于三种非相干软解调算法的turbo-LoRa系统性能

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基于LoRa的卫星物联网系统接收机同步与非相干软解调方案

Receiver Synchronization and Nonconherent Soft Demodulation Scheme for LoRa-Based Satellite IoT Systems

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