How to Design IoT Systems

By Paromik Chakraborty

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Now let’s talk about the frequency, which determines the range and data-throughput capacity. For IoT applications, sub-1.0GHz and 2.4GHz are the most used frequency ranges. Unlike the large data flow during media streaming or voice/video calls, IoT applications are associated with small data packets.

Now, many developers opt for 2.4GHz frequency range owing to its popularity in mainstream applications. This frequency range does provide higher data throughput capacity but not without challenges. First, the 2.4GHz array has a lower range of coverage and poor penetration through obstacles. More importantly, this frequency has a heavy traffic of data packets coming from other devices like microwave ovens and Wi-Fi devices. This creates the problem of signal interference.

Wi-Fi IoT module (Image source: makerstream.blogspot.in)
Wi-Fi IoT module (Image source: makerstream.blogspot.in)

Sub-1.0GHz range, on the other hand, offers greater coverage range and sensitivity in lieu of data volume throughput. Distributed infrastructure can greatly benefit from its long-range characteristics. Moreover, data transmission through obstacles is possible.

Char suggests, “Since sensors of an IoT system generate small data throughout the day, sub-1.0GHz frequency is suited for most applications as it consumes much less power and provides connectivity for years on a battery.”

For instance, IoT systems in agricultural fields or oil and gas industries will share very low-volume data such as soil pH, moisture level and gas level. A sub-1.0GHz frequency can efficiently cover the complete perimeter while consuming much less power.

Coming to wireless standards, while 802.11ac is the most popular Wi-Fi standard in the market, a newer iteration called IEEE 802.15.4 is gaining prominence for the IoT.

Creating a power-efficient system

For IoT applications, designers need to focus on power requirements. Batteries used in these systems are expected to last up to 20 years without requiring much manual intervention. The uniqueness of IoT design elements is their ability to sleep when not in use.

Gaurav Sareen, country head-India, Sigfox, explains, “The transceiver wakes up only when it is supposed to transmit data. As soon as it is done, it goes back to sleep. So, the hardware is essentially asleep most of the time. That is how it conserves energy.”

IoT systems consume power in two modes: dynamic (when the hardware is active) and static (when the hardware is asleep or in standby mode). It is essential to keep these factors in check. Consumption of both the MCU and the transceiver are considered. 32-bit MCUs can transmit data faster. Therefore their dynamic consumption can be much less, enabling the chip to save more energy. FPU compatibility further enhances efficiency. Large-scale applications in businesses can greatly benefit from FPU-supported MCUs.

Key IoT components (Image source: rfpage.com)
Key IoT components (Image source: rfpage.com)

Software for security

Security solutions are essential to ensure that no part of the system (hardware, software or network gateway level) is compromised.

Sareen mentions, “Secure Elements (SE) are in use to ensure safety at hardware level. An SE itself is an additional hardware component that encrypts data and checks authenticity of the device receiving it. The network layer is secured by hiding the data in motion with advanced encryption schemes (AES). Data cannot be breached while being transmitted through network gateways. Finally, data itself is tested in the application layer to ensure it is infection-free.” Authentication levels, including passwords and biometrics, provide secured access to all components and data. In addition, there are debug software that ensure proper functioning of the IoT system.

Why it’s the best time

The job of designers is becoming even simpler with manufacturers introducing integrated modules like MCU-cum-transceiver units that facilitate quicker IoT system design. Efficient software tools allow speedy programming of embedded systems. With improved technology and capacities, isn’t this the best time to be an IoT designer?


 

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