The Urban Sprawl of the IoT

As the Internet of Things proliferates, connected cities become smart cities. The complexity of multiple wireless protocols requires a sound embedded operating system to coordinate hardware and software.

Since the industrial revolution in the mid-18th century, people have moved from rural communities to cities in search of work and as they settled, the cities have sprawled outwards. Over 80% of the world’s population are expected to be living in cities by 2025 (Mordor Intelligence), and these cities are expected to be connected, intelligently managed, efficient environments, with smart utility metering, buildings, healthcare, and transportation systems.

Figure 1: Smart homes are expected to grow 24% CAGR 2018-2023. (Mordor Intelligence)

Part of city life is the ‘busy-ness’ with a transport infrastructure to take people from A to B by road or rail, and the network of entertainment, workplaces, and interests in the urban areas. This connectivity is mirrored by the Internet of Things (IoT), which is expected to be one of the main drivers of the connected, or smart, city, enabling increased levels of connectivity in the workplace, the home, and the wider urban areas.

Considering that many estimates put the number of connected devices at trillions, not billions any more, the need to ensure a secure data path for all of those devices is critical.

Connectivity Changes
At the moment, there are a lot of units working in a closed loop system, explains Simon Ford, Senior Director, Product Marketing, Mbed OS, Arm. “These will now be required to be connected and need flexibility to use the right one for the right job,” he says.

Arm’s open source embedded OS is designed for the IoT. Based on the Arm Cortex-M microcontroller, it includes a Real Time OS (RTOS) and drivers for sensors and I/O devices. For connectivity, there are multiple standards to support, such as LTE Cat-M1 (on the 1.4MHz bandwidth), Narrowband IoT (NB-IoT),, a Low Power Wide Area Network (LPWAN) technology, or, for non-cellular or private networks, the Long Range (LoRa) low power wireless technology, or Bluetooth Low Energy. In. In smart cities, LoRa is likely to be used to monitor a long-range infrastructure, such as an industrial estate. Wi-Fi and Bluetooth are likely to be confined to buildings and low power Wide Area Network (WAN) standards, such as NB-IoT and LoRaWAN 1.1 ( (January 2018)

Connectivity has to be ubiquitous. At the same time, connectivity must be secure and able to be managed remotely. And software has to be updated as and when updates are released. “Connectivity unlocks capability,” observes Ford. “We are now moving from a closed loop controller to an interconnected Internet world. This means changes to connectivity and security threat models.”

“Security is not optional,” warns Chris Porthouse, Vice President and General Manager of Device Services at Arm. One focus for Mbed OS is to enable multi-standard connectivity, and to support whatever standard is appropriate. The other, says Porthouse, is to ensure that users are confident the network is secure and know where data is coming from.

“Arm is in a unique position,” says Ford, “offering device level security and able to enhance at the hardware level with TrustZone  [Arm’s System on Chip security technology] for example.”

Platform Security Architecture (PSA)
The Platform Security Architecture (PSA) will be a common industry framework for secure, connected devices. The Arm initiative is supported by semiconductor companies, such as Microchip, Nuvoton, NXP, Silicon Labs, STMicroelectronics, and Renesas; software companies, including Arm Keil, IAR Systems, and Green Hills Software; security specialists, for example Data I/O, Symantec and Trustronic; systems companies, such as Cisco and Sprint; and Cloud companies, including Amazon Web Services AWS, Microsoft Azure, Google Cloud and Mbed OS. It will define different threat models, explains Porthouse. For example, a kettle has a different threat model to a smart meter, but both have data that needs protecting.

Figure 2: Arm’s PSA initiative is supported by giants from semiconductor vendors to Cloud platform providers. (Image: Arm)

The aim is to define security functions and guarantee a platform that allows developers to deploy the IoT in the target application. PSA will establish security parameters and implement them without thinking, continues Porthouse. “Security won’t be a hard decision, although there may be trade-offs, but not at the expense of timescales.”

Considering that many estimates put the number of connected devices at trillions, not billions any more, the need to ensure a secure data path for all of those devices is critical.

The Mbed OS is designed to help companies take the IoT to the target application. Its ecosystem of partners’ offerings provides hardware, for example, that is RF-certified, together with proven security and Cloud services. With half of the Mbed OS contributions made by partners, the open source project can help customers meet the new techniques that are thrown up by the IoT, making it a huge and complex area of design. As applications and their appropriate wireless technology standards continue to emerge, this trend towards complexity is set to escalate.

 Partners Build Cities
Arm has been working with partner Advantech to add elements to its traditional base of IoT customers. Its sensor nodes, IoT gateways, and WISE-PaaS/EdgeSense software for smart edge computing are built on Arm’s Mbed OS and mbed Cloud technologies.

Figure 3: Advantech’s starter kit introduces developers to LoRa and Mbed OS.


A LoRa module and starter kit includes Advantech’s WISE-1510 LPWAN LoRA IoT node, the WISE-DB1500 development board with built in temperature and humidity sensor, the WISE ED20 debug board, Arm Mbed OS support, accessories and Quickstart guide (Figure 3).

For long range IoT, such as smart lighting and smart metering, Advantech offers the WISE-1510 M2.COM sensor node, based on the standard M.2 sensor form factor, commonly used in IoT applications to combine wireless connectivity and computing performance. M2.COM was created by Advantech, Arm, Bosch,, Texas Instruments and Sensirion and is based on Mbed OS. It has an Arm Cortex-M4 processor and LoRa transceiver and is suitable for smart cities as it has interfaces for sensors and Input/Output (I/O) control, including Universal Asynchronous Receiver/Transmitter (UART), Inter-Integrated Circuit (I2C), General Purpose I/O (GPIO), Pulse Width Modulation (PWM) and Analog to Digital Conversion (ADC), low power consumption.

Caroline Hayes has been a journalist covering the electronics sector for more than 20 years. She has worked on several European titles, reporting on a variety of industries, including communications, broadcast and automotive.



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