Building and testing cloud-connected wireless sensors

Wireless technology is a key driver of the Internet of Things. The global IoT market-research firm ON World predicts that the industrial wireless sensing IoT market alone will reach $35 billion by 2021.

“Today’s WSN and associated cloud technologies provide the key elements for the industrial IoT: multiyear battery-powered wireless nodes, IP addressability, fieldbus tunneling, and cloud-based provisioning and management systems,” said Mareca Hatler, ON World’s research director and a contributor to a new report on the topic.¹

The researchers found that short-range wireless mesh technologies such as WirelessHART and ISA100.11a as well as Wi-Fi, Bluetooth, and proprietary solutions will make up the majority of the market over the next five years, but they add that adoption of low-power wide-area-network (LPWAN) technologies such as LoRa, Sigfox, LTE-M1, and NB1 will increase even faster.

To prepare for wireless IoT proliferation, test-equipment makers and component manufacturers are rolling out products ranging from crystals to communications test sets.
In the latter category, Anritsu has announced a Network Mode for its MT8862A wireless connectivity test set (Figure 1), which is an instrument capable of supporting various WLAN protocol standards such as IEEE 802.11ac/n/a/g/b. Anritsu said that with the new mode configuration, the MT8862A serves as an efficient manufacturing test solution to verify WLAN chipsets designed into IoT devices as well as smart home electronics, connected cars, and smartphones.

Figure 1. MT8862A wireless connectivity test set with new Network Mode
Courtesy of Anritsu

The company said the new mode makes the MT8862A the industry’s first solution capable of measuring the performance of an 802.11ac-capable WLAN DUT in the actual operating state. RF performance characteristics such as Tx power and Rx sensitivity as well as waveform coverage range can be measured over-the-air (OTA) using the Network Mode, which eliminates the need for dedicated vendor-provided test modes typically required for WLAN device verification. Removal of a physical connection establishes a more accurate representation of the actual DUT performance in a real-world environment, as the measurements take into consideration the effect of the internal wireless antennas.

The MT8862A can be operated remotely via a web browser from a control PC connected by Ethernet. This configuration simplifies conducting measurements by eliminating more complex setups for more efficient testing.

Engineers realize numerous advantages when using the MT8862A compared with conventional WLAN test equipment, Anritsu said. The MT8862A can be integrated into a production line and is simple to maintain and calibrate, thereby reducing test system costs and increasing production throughput.

Cellular NB-IoT

WLAN technologies based on the IEEE 802.11 standard will play a role in IoT wireless sensor networks, but so, too, will LPWA services for applications such as smart metering and tracking. Currently, 2G and 3G technologies play a role here, but the 3GPP has developed Narrow Band IoT (NB-IoT) as a new cellular air interface based on 4G technology and adapted to the requirements of machine-type communications.

In support of NB-IoT, Rohde & Schwarz announced that China Mobile Communications Corp. (CMCC) has chosen Rohde & Schwarz as a partner to perform the first NB-IoT base-station tests in accordance with Release 13 Cat-NB1. The CMCC team tested the base station’s RF performance, applying test cases in areas of transmission power, spectrum analysis, group timing and delay, and coverage capability. In the next step, performance tests will include fading scenarios, with the fading capabilities of the R&S SMW200A vector signal generator offering a one-box solution.

Rohde & Schwarz said its solution for base-station testing for generation and analysis of NB-IoT signals consists of the R&S SMW200A vector signal generator and the R&S FSW signal and spectrum analyzer, which already have been used at leading manufacturers of mobile network infrastructure for base-station tests. The NB-IoT signal analysis is performed by the R&S VSE vector signal explorer software option. Users will be able to upgrade to NB-IoT capability to support NB-IoT ecosystem success.

Keysight Technologies also is focusing on 4G initiatives, including Cat M1—an IoT-centric variety of LTE that uses 1.4 MHz of spectrum to deliver 300 kb/s to 400 kb/s. The company recently announced that as part of its plan to help accelerate the deployment of IoT technologies, device manufacturers now are able to verify that their Cat M1-capable products comply with a North American carrier’s Cat M1-focused test plan by using the Keysight’s Anite SAS Interoperability Test. Keysight said the carrier validated the test plan following successful execution of test cases using a device equipped with Qualcomm Technologies’ MDM9206 LTE IoT modem.

Keysight said it offers designers the ability to optimize IoT designs for critical performance attributes such as power consumption, RF performance, and interoperability by simulating the real world in the lab using the Keysight UXM wireless test set (Figure 2). The company reports that the UXM is the world’s first wireless test set to demonstrate connectivity with an NB-IoT device that complies with NB-IoT standards. NB-IoT is a standards-based low-power wide-area technology developed to enable a wide range of new IoT devices and services.

Figure 2. UXM wireless test set with extensible architecture
Courtesy of Keysight Technologies

“Keysight’s capability to support Cat M1 and NB-IoT technology using Qualcomm Technologies’ LTE IoT modems has resulted in IoT industry-leading design and test solutions,” said Giampaolo Tardiolo, senior director for Chipset Mobile Test at Keysight Technologies. “These solutions help customers bring reliable IoT-enabled devices to market more quickly.”²

SDK for Thread

On the component front, Nordic Semiconductor announced that it is addressing Thread networking with the release of its nRF5 SDK for Thread. The SDK is designed to utilize the IEEE 802.15.4 PHY support introduced on Nordic’s nRF52840 multiprotocol Bluetooth low energy SoC. In addition, the Nordic nRF5 SDK for Thread also adds a Device-Firmware-Update (DFU)-over-Thread network feature similar to the OTA DFU feature employed in other existing Nordic SDKs and chips.

The company said its nRF52840’s RAM (256 kB of RAM and 1 MB of flash memory) enable the SoC to run both the Thread and Bluetooth low energy protocol stacks from the same chip. In addition, the nRF52840 is able to run the Thread protocol at accelerated processing speeds by using its built-in ARM CryptoCell-310 cryptographic accelerator—which offers best-in-class security for Cortex-M based Bluetooth low energy SoCs—to run the Thread security algorithms.

The Thread Group describes the Thread stack as “… an open standard for reliable, cost-effective, low-power, wireless D2D (device-to-device) communication. It is designed specifically for Connected Home applications where IP-based networking is desired and a variety of application layers can be used on the stack.”³

The goals are simple network installation, security, low power, support for large and small networks, and reliability. Spread-spectrum technology at the physical layer provides adequate range and immunity from interference. The standard is based on the IEEE 802.15.4 PHY and MAC layers operating at 250 kb/s in the 2.4-GHz band.

Nordic says Thread is built around a developer-friendly 6LoWPAN⁴ mesh network. Prime “home Internet of Things” target applications for Thread include home automation, appliances, access control, climate control, safety, lighting, healthcare, and security systems.

“We are delighted that Nordic Semiconductor recognizes the developer and consumer value of the Thread specification,” said Grant Erickson, president, Thread Group. “With Thread, product developers and consumers can easily and securely connect more than 250 devices into a low-power wireless network that includes direct Internet and cloud access for every device. We’re pleased to see Thread Group member products hitting the market.”⁵

“Nordic Semiconductor has been a valuable contributor to OpenThread,” added Jonathan Beri, product manager, platform, Nest. “The Nordic nRF5 SDK for Thread fully leverages the highly portable nature of OpenThread. It’s a great example of how OpenThread can significantly accelerate the deployment of Thread in wireless devices to bring customers secure and reliable connected products.”

“We see Thread as one of the leading wireless technologies currently emerging in the home IoT space,” commented Geir Langeland, Nordic Semiconductor’s director of sales and marketing. “This is why we have decided to strategically invest our world-leading R&D ultralow power wireless expertise into contributing toward the ongoing development and evolution of the OpenThread software stack.”

As well as the unique support for DFU-over-Thread, the Nordic nRF5 SDK for Thread includes a prebuilt OpenThread stack for the Nordic nRF52840 SoC, examples of all the different Thread roles, support for an OpenThread network co-processor, a CoAP application layer example, a border router and cloud connectivity example, and a range of PC tools including a Thread topology monitor.

The Nordic nRF5 SDK for Thread is now available in Alpha release with full production scheduled for Q4 2017, aligning with the full production of the Nordic nRF52840 SoC.

Sigfox security

STMicroelectronics is addressing security concerns with IoT applications. The company recently announced the expansion of its STSAFE family of secure elements with the introduction of a plug-and-play solution that provides state-of-the-art security features to devices connected to the Sigfox LPWAN.

STSAFE-A1SX connects to the microcontroller of the IoT application or module via an I2C connection. The chips are provisioned in ST’s secure-personalization center with device ID and keys that allow plug-and-play secure connection to the Sigfox cloud and further ensure data-exchange integrity and confidentiality. Whether the frame is an uplink or downlink message, the STSAFE-A1SX secure element generates or verifies payload proof of integrity as well as optional encryption or decryption. Keys and other secrets are protected inside the secure element during manufacturing and over the end device’s full life.

“It’s more important than ever to consider and plan the security architecture at the very beginning of the design and development of an IoT solution,” said Laetitia Jay, CMO at Sigfox. “Working closely with STMicroelectronics has been fundamental to offering state-of-the-art certified tamper-resistant security to our ecosystem of partners and customers. The integration of the ST secure element with the Sigfox libraries, the STM32, and the S2-LP sub-1-GHz transceiver provides an ultralow power, high-performance turnkey solution that brings end-to-end security in IoT and sensor-to-cloud applications to the next level.”⁶

“By executing Sigfox security services within our certified tamper-proof STSAFE-A1SX, we support Sigfox Ready device makers and Sigfox application providers to implement state-of-the-art end-to-end security,” added Laurent Degauque, secure microcontroller marketing director, Microcontroller and Digital ICs Group, STMicroelectronics. “The STSAFE-A1SX makes security over the Sigfox network even stronger and more straightforward. Our customers simply attach this secure element to their general-purpose MCU, such as an STM32, and focus on application development.”

Like other members of the STSAFE family, the STSAFE-A1SX will come with an ecosystem of tools and software to speed its adoption by developers with or without expertise in secure designs. The device is available on expansion boards directly compliant with the popular STM32 Open Development Environment.

Tiny crystal for IoT

Kyocera announced that it has developed what it calls the world’s smallest crystal unit for smartphones, wearables, and other electronic devices. The new CX1008 quartz crystal unit (Figure 3) measures 1.0 x 0.8 mm yet delivers the same electrical characteristics as Kyocera’s conventional CX1210 model (measuring 1.2 x 1.0 mm), enabling it to be adopted without circuit-board revision. Samples are available now with mass production slated for early 2018.

Figure 3. CX1008 quartz crystal
Courtesy of Kyocera

Kyocera reports that the trend toward smaller, more functional smartphones and wearable devices requires smaller, better-performing crystal units. Traditionally, however, it was believed that miniaturizing crystal units beyond a certain point would compromise their performance, since electrical characteristics (such as equivalent series resistance) degraded as the device became smaller. However, Kyocera said it has succeeded in downsizing the crystal unit while maintaining its electrical characteristics through its own crystal-element design technology along with a process that Kyocera developed jointly with Associate Professor Kazuya Yamamura of Osaka University.

Kyocera said that based on this technology, it will accelerate the development of new low-frequency, high-frequency, and high-precision oscillators for such applications as automotive electronics, advanced driver assistance system technologies, IoT devices, wireless network base stations, and 5G mobile communications.

In related news, Kyocera announced that its Kyocera Communication Systems subsidiary has started providing IoT network services in Japan based on the Sigfox global IoT network. The service now is available in Tokyo, Kawasaki City, Yokohama City, and Osaka City and is planned to reach Japan’s 36 major cities by early 2018 and nationwide by 2020.

Kyocera cites a 2015 white paper titled “Past, Present and Future of ICT,” published by the Ministry of Internal Affairs and Communications, indicating that IoT market continues to grow worldwide with the number of connected devices estimated to reach around 53 billion by 2020. The goal of the Sigfox initiative is to enable low-cost IoT implementations while extending battery life for sensors delivering low data rates.

The Sigfox initiative marks the first availability of the Sigfox network in the fast-growing Japanese market, Kyocera said. Machina Research cites Japan as the third largest IoT market in the world behind the United States and China.⁷

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