Low Power devices - Integration in IoT systems

Introduction

All of us who work in electronics, telecommunications, or IT are familiar with Moore's famous law, which predicted the doubling of the number of transistors on a microcontroller and has been accurate year after year, bringing this number to nearly 50 trillion transistors where we stand now in 2023, starting from just a few thousand back in the seventies.

A logarithmic progression that has opened up a plethora of new computing and processing possibilities, taking Edge computing and portable devices to another level of capabilities.

But these computing capabilities have an immutable requirement so far (and I believe also in the future): energy. Without it, there is no processing, no communication, no data. Therefore, it is not at all crazy to place the law of Moore and the evolution of the available energy density in devices on a similar level of importance.

It is easy to realize that they have not been by any means parallel lives.

Modern batteries were born in the 19th century, while transistors as we know them in the 1970s. Therefore, batteries would have a 130-year "head start." Transistors have multiplied their number by 50 million, while energy density (Wh/l) has only increased by 250.

Leaving aside the physical considerations of both technologies, which are obviously different, the rate of evolution of batteries has not followed that of processing capacity. That's why it has been necessary to invest in reducing consumption to be able to close the gap between them.

Therefore, the concept of Low Power among current devices has become crucial to extending intelligence to the Edge, mobility, and personal devices."

Low Power Ecosystem

The effort of the electronics industry to build devices that are increasingly smaller and consume less has been considerable in recent years. This has led to not only Low Power devices with batteries or very low consumption when connected but also Ultra Low Power devices that operate without batteries. Through Energy Harvesting, these devices can collect and send data continuously, thus avoiding the need for recharging or replacing batteries."

The need for systems with long-lasting capabilities, especially in monitoring, sensing, and controlling physical elements and devices, has led to the emergence of various technologies that allow their implementation. These technologies are basically categorized based on how they connect to the internet or other devices. Therefore, we find those with direct connection capabilities such as:

• Wi-Fi: Perhaps the least Low Power of all, but it allows devices like computers or mobiles with high levels of data transfer and low latency, although its operating range is also limited.

• Cellular: Networks like LTE CAT 1, LTE CAT M1, or NB-IoT allow low-power devices to connect to the internet directly, with very wide connection ranges and diverse transfer volumes. However, these are licensed systems and require a subscription or SIM.

On the other hand, there are mechanisms that require a Gateway as an intermediate device for internet connection:

• Bluetooth: A proprietary protocol that has gained very broad market shares in the consumer environment, with low-power modes but limitations in terms of range, bandwidth, and security.

• ZigBee: With the ability to create mesh networks, communication between devices and with the Gateway allows internet connection with very low power consumption and a wide range of communications. However, it has reduced bandwidth and complex network management.

• LoRaWAN: These very low-power devices can connect to the internet with a Gateway, offering very large communication ranges at the cost of reduced bandwidth.

• Sub-GHz: Extremely low power consumption and considerable communication ranges, but with very limited bandwidth and variable regulations regarding radio spectrum in different countries for data communication through a Gateway to the internet.

All of this comes with a variety of protocols that allow data exchange, such as MQTT, AMQP, HTTP, CoAP, DDS, LwM2M, and many other specific protocols, creating a diverse and complex ecosystem."

Edge or No Edge

Except for cellular and Wi-Fi cases, the integration of Low Power systems often requires Edge devices to connect data to the internet. In these cases, Gateways become essential elements where devices connect and transmit their data. Gateways also serve as processing elements that enable the cleaning and optimization of this data.

Devices capable of connecting directly to the internet (Wi-Fi or cellular) allow skipping this intermediate connection and management layer. However, this approach also means delegating the management of the device's lifecycle to the device itself or to higher layers in the platform where they connect. This is necessary to carry out the necessary control and maintenance tasks, which can be even more complex if we are talking about licensed infrastructure.

Systems that require an intermediate Edge layer often use it to manage the lifecycle of connected devices. This includes onboarding, firmware updates (FOTA), device removal, and disconnection, or even to delegate data processing tasks. In many cases, this intermediate layer is not only necessary by architecture but also due to limitations in the management capabilities of the devices themselves."

Integration of IoT

The increasing standardization of protocols is allowing both IoT devices and platforms to have the necessary compatibility for the integration of any type of device and protocol. Additionally, the Edge layers where many of these devices connect enable the conversion of any type of protocol or data.

Devices with specific infrastructures, such as cellular communication technologies, also have the option to connect through data interconnection gateways to ensure that the data flow reaches its destination in the correct form and time. An example could be the implementation of a specific gateway between NB-IoT and the AWS cloud hub based on IP. This allows the communication of emergency beacons from HelpFlash, connected to the Vodafone network, to bring the data to an IP Cloud platform, ultimately integrating with the DGT platform.

On the other hand, systems that require Edge have the flexibility to scale this layer to provide almost infinite processing and interoperability capabilities. For example, we can connect numerous low-power Bluetooth devices from Roca using a Linux-based gateway. This setup allows for the management of the device lifecycle, updates, bidirectionality for device control, and data processing to optimize information packets to the cloud. Additionally, it enables the incorporation of an additional security layer that restricts both access and the spread of potential network attacks.

In summary, the choice of device, connectivity, and protocol is an important phase to consider in the development of the most favorable use case and business model. The operational maintenance needs of devices (such as battery replacement), the required communication range, the bandwidth needed for data transmission, along with the availability of communication and network infrastructure based on the location of the devices, influence the selection of the most favorable architecture to achieve a positive return on investment and a viable operating model.