Building Wireless Sensor Networks with OpenThread

Overview

This book provides a comprehensive guide to developing applications for Thread wireless sensor networks, focusing on the use of CoAP (Constrained Application Protocol) and the Zephyr Real-Time Operating System (RTOS). It leverages Nordic Semiconductor's hardware, specifically the nRF52840 System-on-Chip (SoC), to demonstrate practical implementation of Thread networking concepts.

Key Visual Description

The introductory page features a detailed network diagram illustrating a typical Thread network setup. It depicts a "Client" and a "Server" communicating, with various nodes identified by numerical labels and roles such as "LOGGER". The diagram showcases data flow, including acknowledgments ("ACK [0x4d20]"), and measurements related to current (e.g., "Ampere meter", "3299 mV", "1.49mA"), time ("10ms", "10.84ms"), and charge ("16.20µC"). A Nordic Semiconductor development board is also visible, highlighting the hardware platform used throughout the book.

Core Topics Covered

The book systematically guides readers through essential aspects of Thread networking:

Introduction to Thread

• Thread architecture, including its link layer (IEEE 802.15.4), network layer (6LoWPAN, IPv6), and transport layer (UDP).
• Advantages such as scalability, security, reliability, low power consumption, and interoperability.
• Disadvantages like limited range, data rates, and complexity.
• Introduction to key platforms: Nordic Semiconductor's nRF52840 SoC, OpenThread, and Zephyr RTOS.

Development Environment Setup

• Configuring the Zephyr development environment for Nordic Semiconductor devices.
• Building and flashing Zephyr applications.
• Utilizing Wireshark and the nRF Sniffer for 802.15.4 packet capture and analysis.
• Using the OpenThread Network Simulator (OTNS) for testing and development.

Thread Border Routers

• Understanding the responsibilities of a Thread Border Router.
• Setting up border routers using Raspberry Pi and nRF52840 Dongle.
• Implementing border routers with Espressif platforms.
• Forming and joining Thread networks.

Thread Networking Fundamentals

• Device roles: Router, End Device, Leader, Border Router.
• Device types: Full Thread Device, Minimal Thread Device.
• IPv6 addressing schemes within Thread networks (Unicast, Multicast, Anycast, Link-Local, Mesh-Local, RLOC, ALOC, GUA).

Application Development and Communication

• Creating basic OpenThread applications with Zephyr.
• Configuring device types, roles, and operational datasets.
• Network discovery, using NAT64 for IPv4 translation, and sending DNS queries.
• Handling multicast addresses and UDP messages.
• Implementing network commissioning processes.
• Using CoAP for communication: messages, requests, responses, and server/client implementations.
• Controlling devices (e.g., LEDs) via CoAP.

Security and Service Discovery

• Securing CoAP messages using DTLS.
• Implementing service registration and discovery using mDNS, DNS-SD, and SRP.
• Using X.509 certificates for enhanced security.

Low-Power Devices

• Measuring and optimizing power consumption for Thread devices using tools like the Nordic Semiconductor Power Profiler Kit II.

Appendices

• Establishing serial connections over USB.
• Debugging tips for OpenThread applications.
• Programming boards with bootloaders (e.g., Adafruit nRF52 bootloader, UF2 conversion).