wM-Bus and LoRaWAN® Demo with LR1121 and LR2021

The evolution of smart metering has transformed how utilities collect and manage metering and consumption data. At the heart of this digital transformation of utilities lies the wireless M-Bus (wM-Bus) protocol, a wireless communication protocol for automated meter reading that has been adopted for over 20 years through the standard defined by the European Normalization Committee (CEN) under the standard series EN13757, encompassing Europe and beyond. In this blog post, we'll explore our recent demo featuring the Semtech LR1121 and LR2021, and discuss how enabling the dual connectivity for wM-Bus and LoRaWAN® is today’s demand of utilities for Smart Metering. 

Enabling Dual Connectivity, a Strategic Requirement for Smart Metering  

M-Bus 

M-Bus: Meter-Bus, is a European standard protocol for remote reading of utility meters. Originally developed in the 1990s, M-Bus was designed as a cost-effective solution for the networking by wire and remote reading of utility meters including electricity, gas, water, and heat meters. The protocol enables two-way communication between meters and data collection systems, making it ideal choice at this time for connecting meters by wire and supporting new applications. 

wM-Bus: Taking Meter Reading Wireless 

In 2003, the Wireless M-Bus (wM-Bus) extended the traditional M-Bus standard into the wireless domain, eliminating the need for physical wiring between meters and collectors. This wireless link and physical layers were standardized under the standard EN13757-4 specifically addressing wireless communication over the license-free industrial -scientific-medical bands on the Sub-1 GHz with different modes operating in 169 MHz, 433 MHz or 868 MHz. 

Key Operating Modes 

There are eight modes of wM-Bus, however only four modes (S,C,T, N) have been widely adopted. The wM-Bus modes define how the meter communicates. Stationary (S) mode is appropriate for meters that only send data a few times a day. Frequent transmit (T) mode is applicable when sending greater amounts of data per day. Compact (C) mode can handle even higher data rates. These three modes operate on 868 MHz. If meters are spread over a wide area and do not need high data rates, then Narrowband (N) mode is more appropriate because the 169 MHz will provide longer range but at the expense of bigger antenna. N mode can triple the areas covered by S, T and C modes. The other four modes – R, F, P and Q – are less common.  

• S Mode: Stationary mode, optimized for battery and stationary operation, commonly used for configuration and setup in short range. Different sub-modes exist (S1, S2). 

• C Mode: Compact mode communication in the 868 MHz - currently the most popular use in smart metering. Two sub-modes: 

• • C1: Uni-directional mode 

• • C2: same as C1 but bi-directional mode 

• T Mode: Frequent Transmit mode, operating at 868 MHz. Two sub-modes:  

• • T1: Frequent transmission mode 

• • T2: Enhanced reception capability 

• N Mode: Narrowband mode, operating at 169 MHz, used for longer range applications. Different sub-modes exist (N1, N2). 

Evolution of Utilities Requirements  

For smart meter data collection, the utility customers can utilize wM-Bus for Automated Meter Reading (AMR) using radio mobile collectors or Advanced Metering Infrastructure (AMI) using fixed network collectors (aka concentrators). Most of time, the smart meters transmit data ignoring if the collection is managed by a mobile collector in walk-by or drive-by method or by installed collectors composing a fixed network. The collectors receiving meter data telegrams can add crucial metadata like timestamps and RSSI (Received Signal Strength Indicator) that will help to monitor the meter and network status. Collectors usually forward all collected meter data to a central system either via cellular, LPWAN or Wi-Fi backhaul connections. 

The value of the European standard (EN13757) for utilities comes with the ease of data integration and interoperability of different meters. Many deployments happened and the installed base of wM-Bus kept growing compared to non-standard solutions. But the limited range of Frequency Shift Keying (FSK) radio used in wM-Bus and the higher cost of AMR/AMI system compared to manual reading made it hard to justify adoption everywhere. Many meter readings are still collected manually. 

When the first generation of LoRa transceivers of Semtech arrived in 2013, enabling lower power and longer range compared to the legacy FSK transceivers, the meter industry started to change. With the arrival of LoRaWAN mid-2015 as an open network protocol, it disrupted the smart metering market, giving utilities a broader choice of public and private networks. Nowadays, many European utilities are requiring in tenders of smart metering the dual connectivity with LoRaWAN and wM-Bus.  LoRaWAN for AMI and wM-Bus for AMR, or for AMI.  

There are two main use cases in smart metering requiring dual connectivity with wM-Bus and LoRaWAN supported on the same meter: 

• Two different AMI solutions: for utilities having a legacy infrastructure with wM-Bus and willing to plan migration, or for complementarity between two different networks   
• AMI and AMR: for utilities willing to connect meters on one LoRaWAN network and keeping a fallback method with wM-Bus used for walk-by/drive-by  

wM-Bus Demonstrations with LR2021 and LR1121 

Demo Architecture 

Our demonstration showcases the practical implementation of wM-Bus technology using two different generations of Semtech's LoRa products (LoRa Connect® with LR1121 and LoRa Plus™ with LR2021).  We partnered with EMBIT and WEBDYN for creating a simulated meter environment reflecting different scenario of dual connectivity with LoRaWAN and wM-Bus. 

• For the demo, the wM-Bus collector “Webdyn Easy” is connected by Wi-Fi to the Raspberry PI and forward received data via MQTT 
  

• For the LoRaWAN Gateway and LoRaWAN Network Server (LNS), we embedded both on the Raspberry PI for simplifying the demo (but the gateway could be separated and the LNS could be cloud based). 
  

• The demo requires a Wi-Fi network (preferably local and private in context of exhibition) 

Hardware Components 

• End Device (Meter Simulation): EMBIT module featuring the LR1121 running the LoRaWAN and wM-Bus stacks  
• wM-Bus Collector: Prototype of "new Webdyn Easy" based on Semtech’s LR2021 evaluation board with a development made by Webdyn.    

Demo Operation 

In our demonstration, the EMBIT module functions as an end device simulating a utility meter. The evaluation board transmits dummy meter data to the data collector, which maintains internet connectivity through cellular or Wi-Fi networks. This setup mirrors real-world AMI deployments where meters communicate wirelessly with collectors that aggregate and forward data to utility management systems.  

The demo proves that the Semtech LoRa Integrated Circuits (namely the LR1121 and LR2021) can support the wM-Bus standard for any exchange of communications between meter and collector.  

The interoperability and availability of first solutions enabling dual connectivity with wM-Bus and LoRaWAN is also proven with our demo partners.  

For customers who would like to fully implement their own wM-Bus stack over these LoRa ICs, this can be done now. For those who are seeking to integrate and get technical support, there will soon be a wM-Bus stack available supported by a STACKFORCE stack on LR2021. Semtech will showcase a demonstration of the STACKFORCE wM-Bus stack running on LR2021 in their booth at Enlit Europe. 

This indicates to utilities and meter manufacturers the unprecedented versatility of Semtech LoRa ICs for enabling different use cases each having a specific connectivity scenario. 

Use Cases 

Advanced Metering Infrastructure (AMI) 

For AMI configuration with wM-Bus, our demo shows how the EMBIT module sends wM-bus telegrams to a fixed network infrastructure. The meter data is enriched by the collector with meta data (RSSI level, timestamp of collector) to a central utility system. This approach provides multiple benefits: 

• • Real-time or near-real-time meter data collection enabling automated billing and index accuracy 
  • Scalability of network: it’s possible to add more collectors to densify and collect more meters and it’s possible to add wM-Bus repeaters to extend coverage if needed
  • Remote alarm management 
  • One-way or two-way communication capabilities 

Advanced Metering Infrastructure Demo Sequence

Demo Sequence Description: 

• • The meter transmits data at a rate of every 15 seconds in a wM-Bus telegram at 868 MHz in mode C1

• • Collector adds a reception timestamp and RSSI level to each received telegram

• • Meter data is aggregated by the collector

• • Collector forwards each telegram automatically to Central System

• • Dashboard shows a simple view of wM-Bus telegrams

In the demo, steps 2 thorough 4 are executed automatically in a single sequence per telegram over Wi-Fi

Real-world Scenario:  

• • Step 1: Transmission rate (TX) will be predetermined by the utility and the meter manufacturer, not necessarily every 15 seconds
  • Step 4: Transmissions are grouped and scheduled
  • Step 5: Exception handling: automatic retry mechanism; customer service is notified. It’s possible to schedule a mobile collection with walk-by/drive-by for persistent non-communicating meters
  • Step 6: Billing integration
  • Step 7: Advanced analytics including water consumption analysis, network performance metrics, battery life prediction, and alarm and meter management. 

Automated Meter Reading (AMR) 

The AMR use case demonstrates a more flexible, lower-capex approach to meter reading. Key benefits include: 

• • Minimal Infrastructure Investment: saving cost of a fixed network infrastructure 

• • Flexible Data Collection: Support both walk-by and drive-by reading scenarios 

• • Protocol Flexibility: in Europe predominantly, a common usage for AMR is wM-Bus modes C1 or C2  

In this configuration, meters transmit data regardless of collector presence (no acknowledgment is required). Mobile collectors – whether handheld devices, vehicle-mounted systems or even drone-based platforms - capture these transmissions opportunistically. These mobile collectors then regroup all telegrams and forward the data collected to central utility system via cellular or Wi-Fi connections. 

Advanced Meter Reading Demo Sequence 

Demo Sequence Description: 

• • The mobile collector listens for meters sending index wM-Bus telegrams at 868 MHz for collecting data in short range in mode C1 every 17 seconds

• • Collector adds a reception timestamp and RSSI level to each received telegram

• • Meter data is aggregated by the collector

• • Collector forwards each telegram automatically to Central System

• • Dashboard shows a simple view of wM-Bus telegrams

In the demo, steps 2 thorough 4 are executed automatically in a single sequence per telegram over Wi-Fi

Real-world Scenario:  

• • Step 1: Transmission rate (TX) and mode C or T will be predetermined

• • Step 4: Transmissions are grouped and scheduled over a cellular network

• • Step 5: Billing integration 

Hot Switch Scenario 

One of the key advantages of dual connectivity with Semtech LoRa IC is demonstrated by the "Hot Switch" capability, developed by our partner EMBIT using the LR1121 modem E. This technology enables two critical use cases: 

• 1. Fallback Capability 

Provides continuity of service with connectivity redundancy by allowing automatic switching between the two communication protocols when primary connectivity is compromised. Meters can switch automatically from LoRaWAN to wM-Bus and vice-versa while keeping the network context. With this Hot Switch from EMBIT, meters can seamlessly return to the LoRaWAN network without having to make a new “Join Request”.  

2. Migration Path from wM-Bus to LoRaWAN 

A deployment of meters having dual connectivity and Hot Switch allows automatic migration from wM-Bus to LoRaWAN as soon as the network coverage is available. 

Hot Switch technology offers: 

• • Reduced Risk: Eliminates the need for field technician visits during network transitions 

• • Simplified Network Changes: Seamless protocol switching throughout the meter's lifetime 

• • Context Preservation: No loss of network context data or security keys 

• • No Re-joining Required: Maintains network association when switching protocols 

The system supports bi-directional communication at 868 MHz, enabling both data collection and remote meter configuration without service interruption. 

Technical Advantages 

The wM-Bus implementation with LR2021 offers several technical advantages: 

1. 1. Multi-mode Support: Ready for wM-Bus and full compatibility with all existing wM-Bus modes through the partner software stack 
   2. Flexible Deployment: Ready for AMR and AMI, for any fixed and mobile collection scenarios  
   3. Future-proof Design: Built-in capability to transition between wM-Bus and LoRaWAN 
   4. Robust Communication: Bi-directional capability in supported wM-Bus modes (C2, T1, T2, N), and unidirectional capability in mode C1 
   5. Standard Compliance: Full compliance to EN13757-4 standard for wM-Bus specifications 

Hot Switch Demo Sequence 

Demo Sequence Description: 

Meter can switch from LoRaWAN to wM-Bus and vice-versa and keep the network context (Hot Switch).   

1. 1. The meter sends transmissions in LoRaWAN at 868 MHz with an acknowledgement signal (ACK) from the LoRaWAN network every 15 seconds 
   2. When the meter detects a missing ACK (operator disables gateway to simulate unavailability of the network), the meter then switches to wM-Bus at 868 MHz mode C1
   3. The meter sends wM-Bus telegrams every 15 seconds while also continuing to send confirmed LoRaWAN uplinks to determine when the network becomes available again
   4. The collectors receive the wM-Bus telegrams, regroups them and forwards them to the Central System
   5. Dashboard shows a simple view of wM-Bus telegrams
   6. Reporting on which meters switched to wM-Bus 
   7. Once LoRaWAN network is back (operator reenables the gateway to simulate availability), the meter will receive ACK from network and stops transmitting wM-Bus telegrams and continues only with LoRaWAN uplinks

Real-world Scenario:  

• • Step 2: The utility and meter manufacturer determines the exact conditions of network unavailability for switching to wM-bus

• • Step 5: Billing integration 

Conclusion 

The wM-Bus demo with LR1121 and LR2021 proves a significant support for the enablement of dual connectivity scenarios in smart metering. By combining the flexibility of wM-Bus and LoRaWAN protocols with innovative features like Hot Switch technology, we're enabling utilities to deploy more adaptable, future-proof metering infrastructures. 

Whether implementing a full AMI system with fixed network infrastructure or opting for the flexibility of AMR with mobile collectors, our solution provides the versatility needed to meet diverse deployment requirements. The ability to seamlessly transition between wM-Bus and LoRaWAN ensures that investments made today will continue to deliver value as network technologies advance. 

As the smart metering landscape continues to evolve, solutions like our LR2021-based wM-Bus implementation will play a crucial role in enabling utilities to deliver more efficient, reliable and data-driven services to their customers. 

For more information about implementing wM-Bus solutions with LR2021 or to schedule a demonstration, please contact our technical team.

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