WHITE PAPER Why LoRaWAN Is Key to ® AMI Network Systems Patrick van Eijk Senior Director IoT Solutions semtech.com LoRaWAN®, a MAC layer LPWAN protocol specification defined and managed by the LoRa Alliance® as well as recognized as a global standard by the International Telecommunication Union (ITU) since 2022, is an excellent choice for Advanced Metering Infrastructure (AMI) network systems to not only connect smart meters and streetlights, but also provide connectivity for a host of other IoT devices in smart city and asset tracking verticals around the globe. This article explores the features and benefits of a LoRaWAN network with AMI in mind especially for deployments in North America. Introduction When LoRa® transceiver chips from Semtech first came to market more than a decade ago it quickly became apparent that the RF properties of the LoRa Spread Spectrum modulation outweighed the legacy use of Frequency Shift Keying (FSK) Modulation in Advanced Meter Reading (AMR) systems which are typically implemented as a drive-by solution where a mobile data collector gathers metrology data as it passes nearby water, gas or electric meters. The innate ability of a LoRa radio to demodulate a signal down to 17dB below the noise floor gave it an instant advantage over traditional and legacy FSK-based AMR systems. This higher link-budget that a LoRa radio offers over FSK radios benefits LoRa-connected smart meters (and other IoT devices) in two ways: Longer Range Lower Power Gateways that collect data from smart meters using LoRa devices can be further away from the meters and therefore cover a larger meter deployment area. The extra link-budget allows for successful metrology reads from meters located in difficult to reach areas, like pits with metal lids or deep indoors (basements). This results in lowering the overall cost of ownership of a LoRa-based solution. Transmitting at lower power levels over the same distance as comparable FSK connected smart meters, LoRa-based metering solutions can last 10 to 20 years on the same battery, thereby lowering the total cost of ownership. Why LoRaWAN Is Key to AMI Network System Semtech White Paper 1 Before the LoRaWAN® specification was created in 2015, LoRa® already had caught the eye of water meter OEMs in China, Europe and the U.S. who were using FSK in their AMR capable meters. These OEMs quickly pivoted to Semtech’s LoRa transceivers in new meter designs because LoRa transceivers can also operate in FSK mode, thereby guaranteeing backward compatibility with existing FSK-based AMR technology and allowing for a smoother product migration to LoRa technology. However, the fact that these LoRa/FSK transceivers operated as a physical layer device only meant that each vendor needed to implement their own MAC network layer protocol on top of LoRa, limiting the adoption and growth of LoRa technology. With the creation of the LoRa Alliance® in 2015, a standards-based MAC layer protocol was developed called LoRaWAN to solve these issues. The LoRa Alliance and its Ecosystem ® In the eight years since its creation, the LoRa Alliance has grown into an ecosystem of 400+ world-wide members, comprising device makers, gateway OEMs, chip and module suppliers, public network operators, solutions providers and IoT platform providers. Its members include metering OEMs like Diehl, Honeywell, Kamstrup, Minol-Zenner, Mueller, Neptune, Pietro Fiorentini and Sagemcom. The latest OMDIA LPWAN report lists LoRaWAN and NB-IoT as the two premier IoT technologies that will experience the most growth between now and 2028 as shown below. Why LoRaWAN Is Key to AMI Network System Semtech White Paper 2 AMI Network Systems Based on LoRaWAN ® LoRaWAN is a proven LPWAN technology with excellent characteristics that lends itself to AMI network systems. Features include: long range, low power, and a star network implementation a high level of network security the ability to acquire the various components from a multi-source value chain ecosystem preventing vendor lock-in at various levels. Despite these facts, concerns are sometimes raised towards the use of LoRaWAN in AMI network system implementations by utilities and municipalities in general. Hesitation in embracing LoRaWAN at this juncture has primarily been due to unfamiliarity with and unawareness of the LoRaWAN connectivity with concerns about maturity, IP ownership, performance, and security. The goal of this article is to provide a solid baseline as to why LoRaWAN connectivity is indeed a great fit for AMI network systems. While there are LoRaWAN implementations of AMI networks for electric meters (Vision Metering is a great example), this article focuses on AMI Network Systems for water and gas metrology, since these types of meters are battery operated and need to last 10-20 years, producing a much smaller amount of data compared to smart electric meters. The LoRaWAN standard and network were engineered with battery powered IoT devices in mind, which includes smart water and gas meters. Why LoRaWAN Is Key to AMI Network System What makes LoRaWAN a great fit for AMI? Today, LoRaWAN connected devices can be found across a wide variety of markets including not only metrology, but also logistics, smart building, smart city, and smart agriculture. A LoRaWAN network can either be implemented as a dedicated network or a multitenant network providing a utility or municipality planning to deploy a smart metering project with more options and flexibility regarding network usage, ownership and management. In the following sections we will review the key aspects of a LoRaWAN network with a focus on AMI network systems. Semtech White Paper 3 A Truly Open and Evolving LPWAN Standard Other LoRaWAN network connected devices: There are several advantages to using a truly open and globally accepted standard like LoRaWAN®. First, there is no vendor lock-in for smart water or gas meters nor for any other devices one might want to connect to a LoRaWAN network. Street Light National Electrical Manufacturers Association (NEMA) controllers, Outdoor Air Quality Index (AQI) sensors or parking sensors that indicate if a parking spot is free or taken are good examples. Second, unlike with competing licensed spectrum or RF-mesh based AMI network systems, there is no gateway vendor lock-in as gateways can be acquired from a variety of OEMs. Open standards are known to drive down costs, while proprietary solutions keep costs elevated. Another key benefit of an open-technology standard like LoRaWAN is that the evolution of the standard is driven by customer needs through the LoRa Alliance®. The membership-based approach that the LoRa Alliance takes ensures that its members drive the specifications forward, evolving through contributions from key members as part of Technical, Marketing and Certification Committees. New innovations such as Device-to-Device (D2D) communication which allows a LoRaWAN connected device, like a Residential Methane Detector (RMD), to communicate directly to a LoRaWAN connected gas meter with a built-in shutoff valve. If the LoRaWAN network were unreachable, as might be the case in a natural disaster, D2D would ensure the safety of those who might be affected by a rogue gas leak. Another recent innovation is the LoRa-enabled relay, a low-cost, battery powered device to extend the range of LoRaWAN connected devices. This eliminates the need for a full gateway. Additionally, the LoRaWAN standard continues to be enhanced with new features such as support for additional cipher suites (beyond the standard 128-bit AES encryption as discussed in section 2.6) and rekeying options for meter endpoint Root Keys. Why LoRaWAN Is Key to AMI Network System Street Lights Outdoor Air Quality Sensors Parking Sensors Semtech White Paper 4 A Dedicated Versus a Multitenant LoRaWAN Network Dedicated Network ® LoRaWAN supports both dedicated and multitenant network implementations. While this choice has no bearing on meter endpoints or gateways, it does affect how gateway capacity is allocated as well as the total cost of ownership (TCO). In a dedicated network all the gateway capacity would be allocated to a single utility’s or municipality’s AMI network to which they can connect their smart meters as well as other LoRa®-enabled end-devices or sensors. In this case the utility or the municipality would be the owner of the gateway infrastructure which requires a capex investment. Multitenant Network In a multitenant network implementation, the network infrastructure is typically owned by a third party who then provides the Network as a Service (NAAS) to the utility or municipality. In this case, the capacity is securely shared between multiple parties. The benefits of a multitenant network are lower TCO, higher network efficiency and better device battery optimization as multitenant LoRaWAN networks typically will have a higher gateway density versus a dedicated LoRaWAN network. Why LoRaWAN Is Key to AMI Network System Semtech White Paper 5 A Star Based Network Architecture A LoRaWAN® network, whether dedicated or multitenant, is implemented as a star network, meaning there is always only a single hop (connection) between the end-device and a gateway, in this case the smart meter or meter reader, to a gateway. The benefit of a star network compared to an RF mesh implementation is increased battery life, as the battery only needs to be used to transmit metrology data from a single meter (itself). AMI meters connected to a RF mesh network need to not only use their battery power to transmit their own metrology data to the headend system but need to transmit metrology data of some or many of their neighboring AMI meters that are too far away from a gateway or data collector and need one or more RF hops to reach the nearest gateway through another meter. One of the operational limitations of an RF mesh network is the fact that the power consumption (and therefore the battery life) of a meter endpoint is hard to predict, as some nodes could be relaying a lot of data from other nodes while others might not. This could potentially result in more frequent battery replacements for an unplanned subset of meters. In a LoRaWAN network, there is no persistent 1:1 connection between an AMI meter and a specific gateway. The absence of a dedicated connection prolongs battery life because the meter endpoints do not have to stay synchronized with a gateway. Furthermore, LoRaWAN networks are highly scalable as gateways can be added as needed without reprovisioning meter endpoints to connect to an added gateway. Why LoRaWAN Is Key to AMI Network System Semtech White Paper 6 High-Capacity Full Duplex Gateways While 8 or 16 channel gateways utilizing LoRaWAN® are the norm for most countries around the world, in North America the FCC allows for 64 channel gateways operating in the 915MHz ISM band. The added benefit from hopping over 50 channels or more (per FCC regulation 15.247) is the fact that endpoints can transmit at 30dBm (1 Watt). Even though higher meter endpoint transmit-power levels reduce battery life, a compromise can be made between the metrology reporting interval and transmit power because the extra 6-8dB of link budget over a typical 22dBm end-device frequently make a big difference for water meters that are often located in a concrete pit under a metal or concrete lid. Water as well as gas metrology data that needs to be passed from the meter through an AMI network system to the headend system (typically cloud based) is small enough to be passed in the payload of a LoRaWAN frame. In efficient implementations, this can be as little as 11 bytes, but can be as high as 254 bytes if needed. Even at an assumed network load of only 5% (meaning 95% of the time there is no data being sent), a 64-channel full-duplex gateway utilizing LoRaWAN can process up to 9 million 11-byte payload uplink messages (equally distributed between the 4 spreading factors; more on spreading factors in section 2.5) in a 24-hour period. With a maximum uplink link-budget of 164dB, AMI meters can be located up to 15 km from the gateway. The long-range capabilities of the LoRa RF modulation means that gateways utilizing LoRaWAN only need to transmit their downlinks to the meter endpoints at 0.5W, compared to gateways from some competitive licensed-spectrum AMI solutions which transmit at up to 60x (30W!) power levels, severely increasing the size of a backup battery needed with each gateway in case of a power outage. As an example, a single full-duplex 64 -channel LoRaWAN gateway can support well over 100k meter endpoints each reporting 24 metrology reads (or more) per day. Intelligent Network Server In a LoRaWAN network, uplink messages from any AMI meter within linkbudget range of any gateway will be processed and transmitted over a secure TCP/IP backhaul link (typically 4G cellular) to a cloud-based network server utilizing LoRaWAN. The network server performs a function called data deduplication where it will delete all additional copies of each LoRaWAN uplink message and only keep the one with the best RSSI/SNR. The network server will then forward the uplink to the head-end system of the utility or to a specific application platform/IoT platform to which the end device belongs. Uplinks (from an AMI meter to a gateway) can be transmitted using one of four different data rates (called Spreading Factors). The fact that these four different Spreading Factors are orthogonal to each other in the RF space (meaning they appear as noise to each other) provides an often overlooked Why LoRaWAN Is Key to AMI Network System Semtech White Paper 7 and extremely valuable feature of LoRa® modulated packets. The orthogonality allows incoming uplinks on the same channel (same frequency) of a gateway at the same time to be processed concurrently because they appear as noise to each other, and because LoRa packets are received well below the noise level. This significantly increases the overall throughput of any gateway utilizing LoRaWAN® (whether it has 8, 16 or 64 channels). Each network server utilizing LoRaWAN employs a dynamic Adaptive Data Rate (ADR) mechanism which controls the SF and power levels of all AMI meters utilizing LoRaWAN (via Network MAC commands sent through downlinks from the network server to the meter). The main goal of the ADR mechanism is to optimize the battery life of the AMI meters by for example having the meters that are located close to a gateway (based on RSSI/SNR levels) transmit their uplinks at a low power level and with the lowest Spreading Factor (SF7). The lower the Spreading Factor, the shorter the time-on-air (transmission time of the LoRaWAN frame) thus reducing overall current usage. Higher Spreading Factors are assigned to meters that are located further away from the nearest gateway and therefore need the additional RF gain (from using the higher Spreading Factor) to close its link-budget with the gateway. By balancing the distribution of the four spreading factors (SF7, SF8, SF9 and SF10), the ADR mechanism directly contributes to the maximization of the processing capacity of the gateways utilizing LoRaWAN therefore increasing the overall LoRaWAN network throughput. Operation in the ISM (915MHz) Band In North America, LoRaWAN networks operate in the unlicensed 915MHz ISM Band. In the U.S., this ISM band is regulated by the FCC’s 15.247 rules to ensure fair coexistence of RF Transmitters. The 15.247 regulation is implemented as follows: It limits end-device transmission power levels and enforces a distribution of these transmissions over different frequencies (channels) by either a frequency hopping requirement or a minimum bandwidth requirement. Unlike FSK or GFSK based AMI systems (operating in licensed or unlicensed bands), LoRa packets can still be received with a SNR below the noise floor, down to -17dB (when using the highest Spreading Factor, SF10). In a LoRaWAN network, gateway diversity boosts network capacity and lowers packet error rates by reducing collisions between uplinks with the same spreading factor. If certain gateways utilizing LoRaWAN channels are experiencing higher levels of interference on a local level, the network server utilizing LoRaWAN can reassign the channel usage as needed. Competing licensed-spectrum AMI network system providers often try to paint the ISM band as some kind of unregulated and noisy wild-west type spectrum. Nothing could be further from the truth. The ISM Band is strongly regulated by the FCC who makes sure that many different products can coexists in this band. For example, the fact that over 80 million smart electric meters managed by some of the largest utilities in some of our largest cities are currently connected to competing AMI networks that operate in this unlicensed 915MHz ISM band is a testament to the fact that FCC regulation works as it was intended. There is no need to pay for overpriced licensed spectrum equipment when it comes to AMI network systems. Why LoRaWAN Is Key to AMI Network System Semtech White Paper 8 LoRaWAN Security ® As for any network, security is one of the most important aspects of a LoRaWAN network. The security implementation of LoRaWAN relies on standards-based, well-vetted algorithms and end-to-end security. The key security characteristics of a LoRaWAN networkdedicated or multitenant- are mutual endpoint authentication between the meter and the network, data-origin authentication, integrity and replay protection and confidentiality. Symmetric cryptography and prior secret key sharing between a meter endpoint and the LoRaWAN network enables a very efficient and secure activation procedure. The security mechanisms for LoRaWAN are based on National Institute of Standards and Technology (NIST) approved Advanced Encryption Standards (AES) cryptographic algorithms. These types of algorithms have been accepted and deployed for many years and are an excellent security implementation for LPWAN networks. The LoRaWAN standard specifically relies on the 128-bit AES cryptographic primitive combined with several modes of operation such as Cipher-based Message Authentication Code (CMAC) for integrity protection and Counter Mode Encryption (CTR) for endto-end encryption of all metrology data between meter endpoints and the head-end system as well as command and control data between the network server utilizing LoRaWAN and the meter endpoints. Unlike cellular devices which need to be provisioned with a SIM card, devices using LoRa® are provisioned with their security credentials at manufacturing, ideally injected into a tamper proof Secure Element. These credentials consist of a set of Root Keys that uniquely identify the meter endpoint, the LoRaWAN network and the head-end system (Application Server). In a secure manufacturing process, these keys are generated by Hardware Secure Modules (HSMs) which are tamper- Why LoRaWAN Is Key to AMI Network System proof physical appliances. This provisioning process allows for low-cost and efficient meter deployments. Once a smart meter utilizing LoRaWAN is deployed, network connectivity is achieved by an Over-The-AirActivation (OTAA) procedure which consist of a JoinRequest and Join Accept message exchange between the meter endpoint and the LoRaWAN network. Since a comprehensive review of the security features of LoRaWAN is beyond the scope of this white paper, additional details can be found here: LoRaWAN security Semtech White Paper 9 Summary Any LoRaWAN® network has key attributes that make it attractive for AMI: scalability, high capacity, long range, low power, ease of deployment, high security, and low cost. The LoRaWAN standard is an open source, member driven protocol and a unique LPWAN technology that should receive serious consideration for any new AMI network implementations service, particularly smart water or gas meters, as well as electric meters where meter read intervals or verbosity can be limited. Explore these valuable links: LoRa Alliance® Academy for LoRaWAN Everynet Senet Tektelic Adtran Viaanix See more examples of LoRa in Action ® 200 Flynn Road, Camarillo, California 93012 | 805-498-2111 semtech.com | Find us, like us, follow us Semtech, the Semtech logo and LoRa are registered trademarks or service marks of Semtech Corporation or its subsidiaries. LoRaWAN and LoRa Alliance are licensed marks. Other registered trademarks that appear in book are property of their respective owners. ©2023 Semtech Corporation. All rights reserved.
