▌Solution Overview
There are many technologies available for reading water meters, which can mainly be categorized into wired and wireless reading methods. Among various meter reading technologies, wireless meter reading is more widely accepted due to its ease of installation and maintenance without the need for on-site wiring. However, some wireless technologies also face application issues, such as short FSK range, poor penetration, and unstable wireless signals. Although GPRS offers good network coverage, it consumes too much power. The emergence of LoRa technology addresses the challenges of transmission distance, network signal stability, and power consumption in meter reading applications. This article recommends a smart water management solution based on LoRaWAN.
The following diagram illustrates the application framework of the water meter/gas meter reading system based on LoRaWAN:
This solution adopts the standard architecture of the LoRaWAN network, achieving end-to-end data transmission. The traditional water meter terminal is designed as a LoRaWAN terminal, and the network server has optimized the data reporting based on the characteristics of the meter reading data.
▌LoRa Smart Water Management Solution Network Architecture
The following diagram shows the network system architecture of this solution:
Terminal Layer – A PCBA with LoRaWAN functionality has been specially designed for water and gas meter applications, and the glue application process for the current water and gas meter PCBA has been optimized. A waterproof box design facilitates the maintenance and replacement of the water and gas meter control system. The LoRaWAN antenna has been designed and optimized for the installation environment of the water meter, using a PCB antenna that has been professionally matched and tested for good transmission and reception performance.
Network Layer – The standard protocol based on LoRaWAN has been adopted and optimized for water meter data processing. Low Power Wide Area (LPWA) technology provides excellent technical support for large-scale data collection systems. A low-cost LoRaWAN relay device has been designed to address the blind spots in LoRaWAN network signals, solving the coverage issue of the LoRaWAN network. The results from pilot testing have shown promising outcomes.
Cloud Platform – The smart hardware cloud platform provides cluster deployment, protocol and service management, etc. The LoRaWAN network server (NS) can be deployed in a private cloud or a public cloud, making project deployment more flexible.
Application Layer – The smart water management application platform is responsible for operation and maintenance management, data visualization, and other tasks.
▌LoRaWAN Water Meter Product
The following image shows the physical pictures of the water meter and module:
To address the issue of MCU firmware upgrades in the future, this solution has also designed a dedicated tool and software that allows for over-the-air (OTA) upgrades via short-range wireless methods, eliminating the need to disassemble the meter casing, thus saving maintenance costs and improving efficiency.
Main Features:
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Minimum -147dBm high link sensitivity
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Maximum 20 km line-of-sight communication distance
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1.5~2.5 km communication distance in urban dense areas
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Maximum 20 floors cross-building communication capability
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Minimum 5uA ultra-low power design, ensuring a product lifespan of 6~10 years
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High accuracy pulse count error: ±1 per year
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Low-latency remote wake-up function
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Smart OTA upgrade function
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Advanced anti-theft water function with remote automatic alarm
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Supports external magnetic signal forced wake-up function
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Seamless integration with water meter device cloud and water plant management platform, ensuring data security
▌LoRaWAN Module
The main chip of the LoRaWAN module uses Semtech’s SX1278 and ST’s ultra-low power MCU STM32L051C8. The module frequency adopts the applicable frequency band in China, 470-510MHz, and supports the LoRaWAN standard protocol.
Main Features:
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Built-in STM32L051C8 processor
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Supports LoRaWAN™ 1.0 protocol stack
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Supports LoRaWAN™ Class A and Class C
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Uses TCXO
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Maximum link budget up to 168dB
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127dB RSSI dynamic range
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9.9mA low receiving current, 200nA standby current
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Supports multiple security encryptions such as AES128/SM4
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Supports modulation methods including FSK, GFSK, LoRa™
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Automatic RF signal detection, CAD mode, and ultra-fast AFC
Various encryption technologies (AES128/SM4) ensure the security of the network and data.
▌LoRaWAN Gateway
The LoRaWAN gateway complies with LoRaWAN protocol specifications, supports multi-channel concurrency, is powered by POE, and includes GPS functionality, with backhaul options including 3G/4G/WiFi. The LoRaWAN gateway has been optimized for anti-interference design to meet various environmental applications.
Main Features:
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Can simultaneously receive traffic on the same channel
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Easy to expand and increase network capacity
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Can simultaneously demodulate 2MHz bandwidth
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Simple star network with no latency
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Adaptive link rate
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Supports up to 100,000 communication nodes
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Transmission power of 27dBm
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Link sensitivity of -157dBm
▌LoRaWAN Network Server
The LoRa network server can be deployed privately or in a public cloud, such as Alibaba Cloud.
Main Features:
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LoRaWAN. MAC
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GW network management and configuration
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EN configuration and OTA
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Data interaction with application servers
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Based on source data to select the best downstream path
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RTCM high-precision positioning differential data broadcasting (optional)
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Scheduling downlink traffic
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GW access quantity: 2000 units
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EN access quantity: >1 million
▌Cloud Platform and Application Platform
The main functions of the smart water meter application platform include:
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Meter reading management (settings, community, water plant management, etc.)
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Product lifecycle management (testing, installation, traceability)
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Operation management (monitoring, upgrades, records, etc.)
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Data visualization (statistics, queries, charts, reports)
The main functions of the smart hardware cloud platform include:
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Uses the Dubbo distributed framework to support large-capacity high-concurrency requests
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Uses Docker container cluster deployment to save resources and time
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Supports OAuth2.0 protocol authentication and authorization
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Supports multiple protocol communications (HTTP, MQTT, TCP/UDP, etc.)
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Real-time request service governance and service monitoring
▌Smart Meter Management Platform, Billing Platform & Smart Life App
The following images are screenshots of the meter reading system backend management interface and the App interface, providing a visual data management backend.
▌Product Testing and Testing Equipment
The research and development and production of products rely on testing instruments and equipment, and professional and complete instruments ensure the quality of the solution design.
▌Solution Deployment Site
The following image shows the deployment site of the solution, where a LoRaWAN network basically covers six buildings, achieving nearly 100% successful meter reading through site design and optimization.
▌Conclusion
This solution is designed based on the standard LoRaWAN protocol and optimized for water meter data applications. During the actual deployment of the LoRaWAN network, there may inevitably be signal blind spots, for which a low-cost LoRaWAN network blind spot relay has been specifically designed to achieve seamless coverage of the LoRaWAN network signal. Additionally, to facilitate the maintenance and upgrade of water meters, an over-the-air upgrade tool has been designed that allows for MCU firmware upgrades without opening the meter casing, simplifying on-site maintenance and software updates.
This solution is also applicable to gas meter reading and other applications.
For solution inquiries, please contact via WeChat iwangzhijie