LoRa Devices and LoRaWAN Protocol Lead Smart Metering into the Connected Future

September 18, 2019 Patrick van Eijk, Semtech

As more cities move toward urbanization, countries all over the world are developing technology that will help fully monitor and control operations. With help from a unified Internet of Things (IoT) platform, cities are able to monitor and/or control a multitude of applications including electricity, water and gas meters, streetlights, waste management and parking.

Traditional utility meter monitoring operations are labor intensive, as they require manual reading and measurement by personnel in the field or remote reading using a short-range wireless technology typically in a drive-by scenario. Meters are often located in dense urban environments, indoors or even underground, which can be difficult or impossible to reach by many wireless technologies. By implementing a smart metering infrastructure comprised of sensors and gateways embedded with LoRa devices, utility companies can collect data remotely and use personnel more efficiently to streamline operations.

According to market research conducted by IHS Markit, current estimates suggest the global smart water meter market will surpass $2B in 2020. With one application, LoRa devices and the LoRaWAN protocol can create a smart metering application across verticals that are scalable, secure and reliable.

Here’s how it all works.

LoRa (short for long range) is a spread spectrum modulation technique derived from existing Chirp Spread Spectrum (CSS) technology. It offers a trade-off of sensitivity versus data rate and bandwidth. It uses orthogonal spreading factors that allow the network to make adaptive optimizations of an individual end node’s power levels and data rates with a goal of preserving end-node battery life.

For example, a sensor located close to a gateway should be transmitted at a low spreading factor since very little link budget is needed. A sensor located several miles from a gateway will need to transmit with a much higher spreading factor, as the increased spreading factor will provide increased processing gain resulting in higher RX sensitivity, but at a lower data rate.

LoRa itself is purely a PHY (Bits) layer implementation. Instead of a cable, the air is used as a medium to transport the LoRa radio waves from an RF transmitter in an IoT device to a RF receiver in a gateway and vice versa. In a traditional or Direct Sequence Spread Spectrum (DSSS) system, the carrier phase of the transmitter signal changes according to a code sequence. When multiplying the data signal with a pre-defined bit pattern at a much higher rate, also known as a spreading code (or chip sequence), a “faster” signal is created that has higher frequency components than the original data signal and, as such, spreads the signal bandwidth beyond the bandwidth of the original signal. In RF terminology, the bits of the code sequence are called chips, in order to distinguish between the longer uncoded bits of the original data signal. When the transmitted signal arrives at the RF receiver, it is multiplied with an identical copy of the spreading code used in the RF transmitter, resulting in a replica of the original data signal.

Semtech’s LoRa devices offer a low cost and low power, yet robust, alternative to a DSSS system that does not require a highly accurate reference clock. In LoRa modulation, the spreading of the signal’s spectrum is achieved by generating a chirp signal that continuously varies in frequency. An advantage of this method is that the timing and frequency offsets between transmitter and receiver are equivalent, greatly reducing the complexity of the receiver design. The frequency bandwidth of this chirp is equivalent to the spectral bandwidth of the signal. The data signal that carries the sensor data is chipped at a higher data rate and modulated onto the chirp carrier signal. LoRa modulation also includes a variable error correction scheme that improves the robustness of the transmitted signal. For every four bits of information sent, a fifth bit of parity information is sent.

Here are a few key features of LoRa devices and the LoRaWAN protocol that make it an optimal solution for smart metering and other smart city applications:

  • Long Range: A single outdoor LoRaWAN gateway enables deep penetration in dense urban environments (indoors or underground) while also providing the ability to connect to sensors up to 30 miles away in rural areas.
  • Geolocation: Enables the ability to track devices without GPS or additional power consumption.
  • Open Standard: The LoRaWAN open specification is a low power, wide area networking (LPWAN) protocol based on LoRa devices. It creates interoperability among applications, IoT solution providers and telecom operators to accelerate adoption and deployment of both private and public networks
  • Low Power: The LoRaWAN protocol was developed specifically for low power devices and enables unprecedented battery life of up to 10 years depending on the application.

There are many companies worldwide leveraging LoRa in smart metering or utility management solutions. In 2018, tens of millions of LoRa-based smart meter solutions were deployed and with constant urbanization, as well as demand for greater efficiency, utility companies need to augment capacity while developing new solutions to optimize management of their existing assets. By implementing a smart utilities infrastructure comprised of sensors and gateways utilizing LoRa devices and the LoRaWAN protocol, utility and metering companies can collect data remotely and use personnel more efficiently to streamline operations. With a strong value proposition to the utilities with flexibility to deploy and/or leverage private and public networks in a cost-efficient manner, along with interoperability at the next work and device levels, smart metering has become one of LoRaWAN’s most successful vertical markets.

LoRa is an established leader in the smart metering industry, creating scalable, secure, and reliable solutions to help customers deliver more efficient metering solutions, thereby reducing waste and utility spending. The arrival of advanced connectivity will encourage the utilities industry around the world to embrace new advancements. Utilities will continue to "get smarter" by leveraging their data and bandwidth capabilities to support a slew of connected devices that will provide increased system resiliency, reliability and security, cost savings, real-time monitoring and communication. As more cities move toward smarter, sustainable and reliable LoRa-based solutions for metering and other smart city applications, the companies using this technology are well positioned to be early leaders in this space.

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