In the Internet of Things (IoT), where billions of small, battery-powered sensors and tags need to receive and transmit small amounts of data, the Sigfox protocol is a made-to-order solution for wireless connectivity. As a low power wide area network (LPWAN) protocol that’s supported by a global connectivity service, Sigfox delivers the kind of energy-saving, low-bit-rate, long-range connectivity that many IoT devices need.
Sigfox saves power by restricting the number of transmissions and limiting the messages—meaning Sigfox tracking devices can stay in the field for three to five years on the same coin-cell battery. Also, since SigfoIntx devices automatically connect only to the in-place Sigfox network, it’s easy to collect data without having to invest in or maintain a local network infrastructure. One low-cost subscription provides global coverage, without roaming charges.
As good as Sigfox is, though, developers are finding that Sigfox is even better when it’s combined with other wireless protocols. Integrating near field communication (NFC), for example, enables smartphone interactions without taxing the battery, while integrating RAIN Radio Frequency Identification (RFID) adds a new level of transparency to the supply chain. Here’s a closer look at how that works.
The NFC protocol supports secure wireless communication between electronic devices that are within 4 cm of each other. NFC is the technology that makes “tap” payments possible and it’s widely used in the consumer segment to support interactions with everyday items.
Now that the Android and iOS operating systems offer native support for NFC, NFC is gaining ground in the IoT. According to market analyst ABI Research, NFC penetration in smartphones is expected to reach 70% by 2023. With more people carrying smartphones (and tablets) with NFC readers on board, more IoT devices are using NFC to communicate.
As part of a Sigfox design, NFC can increase interaction and add functionality. During deployment, for example, NFC can be used to commission or activate the device. With a single tap of a smartphone (or tablet), the device wakes up and connects to the Sigfox network. Since the smartphone supplies power to the NFC tag, the device battery can stay in sleep mode until it’s needed for IoT operation. A smartphone can also be used to read out Sigfox device parameters, check utilization and write configuration parameters. NFC can upload new firmware from a smartphone, and the smartphone can read out diagnostic data or facilitate a post-mortem analysis.
The Sigfox design remains compact, since a connected NFC tag is the only additional IC needed for the layout. The NFC antenna is made from copper traces to the PCB, and the tag itself includes up to 2 kBytes of memory.
Combining NFC and Sigfox is particularly useful in the consumer segment, where it can create engaging consumer interactions and enable remote services, without requiring the presence of a local Wi-Fi or Bluetooth Low Energy (BLE) connection. With an e-bike, for example, the NFC/Sigfox combination can be used to authenticate replacement batteries, in order to combat counterfeiting and can be used to activate or deactivate Sigfox alarm messages if the bike is stolen. NFC can also be used to receive the consumer’s consent to data privacy or register consumer credentials, in accordance with regulatory guidelines like the GDPR. In white goods, such as washing machines and other home appliances, NFC can be part of predictive maintenance programs and can make it easier to diagnose issues and read out failure codes. NFC also gives people quick access to manuals, Wi-Fi setups, customer-service callbacks and other support mechanisms.
In the supply chain, the NFC/Sigfox combination enhances tracking by giving inanimate objects a way to communication with the IoT and with people. In an orchard, for example, a tracker-equipped apple crate can perform outdoor geo-localization using a GPS receiver and/or Sigfox triangulation. Sigfox can record temperatures, monitor movement or shocks and battery voltage, and enable long-range communication. NFC can take care of short-range communication, letting people in the supply chain use their smartphone to store or read data. The tracker design has a multi-year battery life, is dust- and water-resistant, and is cost-effective yet easy to maintain.
The other wireless protocol that Sigfox pairs well with is RAIN RFID, a key enabler in the IoT. RAIN RFID can read hundreds of items at once, without line of sight and at a distance of at least 10 meters. Like NFC, RAIN RFID is a passive technology, so it uses power supplied by the reader and doesn’t need a battery in the tag.
Since RAIN RFID supports real-time asset monitoring and tracking, it’s a leading choice in supply chains around the world. The RAIN Alliance industry association reports that, in 2020 alone, billion RAIN RFID ICs were shipped for use in tagging applications.
There are times, though, when RAIN RFID doesn’t provide the necessary coverage. When items are in transit, for instance, they may be beyond the reach of RAIN RFID readers, and third-party suppliers and logistics companies may not be equipped with RAIN RFID at their facilities. These gaps in coverage create moments when items are offline, and that can lead to logistical issues and generate opportunities for diversion.
Sigfox can be used to fill these gaps, by taking asset monitoring and tracking to places where RAIN RFID either can’t reach or isn’t available. Sigfox-enabled devices can periodically collect information about the location and status of goods at any point along the supply chain and can securely transmit that information through Sigfox’s global IoT network. Sigfox is available in compact modules that can be added to a RAIN RFID design, and Sigfox networks can be set up quickly at partner sites using private or public base stations. When integrating with enterprise resource planning (ERP) systems, the Sigfox payload can include the RAIN RFID tag’s unique ID (UID) or Electronic Product Code (EPC), so there’s no complex remapping or programming required in the back-end operation.
Sigfox makes real-time information available between locations within the RAIN RFID infrastructure. Worldwide coverage is provided by the Sigfox network, so items can report their location from hard-to-reach places while on the move, whether they’re traveling by truck, train, plane or ship.
Sigfox also adds an extra security component by protecting from theft and guarding against diversion into grey and black markets. Sigfox can issue an alarm if a pallet or crate containing individually tagged items is opened or begins traveling in an unauthorized or unexpected direction. An alarm can be sent if an individual box is opened in a location where it shouldn’t be touched, such as at a distribution center or while in transit. Sigfox can even support the use of Incoterms, the internationally recognized commercial terms of sale, by reporting when a subset of pallets leave a location.
As a recognized leader in RF protocols, NXP offers optimized solutions for every key wireless protocol used in the IoT, including Sigfox, NFC and RAIN RFID. We simplify the integration and qualification of designs that use more than one wireless technology, so developers can finish quickly and meet time-to-market requirements.
For Sigfox in particular, we offer the OL2385 system-on-chip solution and, through a third party, offer pre-qualified modules that are ready to run. Our secure NFC tags are fully compatible with Sigfox, and we also offer a dedicated Sigfox Asset Tagging Solution, which can be configured to use RAIN RFID when readers are available. The Sigfox/RAIN RFID tag design includes a rugged casing that’s resistant to dust and water, and a one-year subscription to the Sigfox network for field testing.
To learn more about how NXP is making it easy to use Sigfox in combination with NFC and RAIN RFID, visit www.nxp.com/connectivity.
Thomas has been working in the semiconductor industry for 20 years in various roles in engineering, and joined NXP Semiconductors in the UK as Product Marketing Manager for ZigBee/IEEE802.15.4 solutions in 2007. Since 2015, Thomas is part of NXP’s business line Advanced Analog in Hamburg where he is responsible for automotive and industrial sub-GHz products.
