Is 5G an over-specification for cellular IoT devices?

With its innovative network architecture, 5G supports a wide range of performance improvements for existing applications and creates possibilities for completely new solutions. But not all applications need the enhancements that 5G offers. In many cases, 4G’s technology performance is sufficient. With this in mind, designers should avoid over-specifying mobile device design to use a 5G solution when it’s not necessary to do so.

So when is 5G necessary for your device? Read on to find out.

What does 5G mean for mobile device design?

To deliver improved performance and enable new applications, 5G-NR (new radio) networks use a broader range of frequencies. To utilise these frequencies, antennas designed for 5G should, in theory, be larger than those required for 4G networks. This is because surface mounted antennas use a printed circuit board (PCB) in the device as a ground plane. Often, antennas are designed to be placed on the edge or corner of the PCB and must have a clearance area between the antenna and other components.

Another factor that affects device size is the ground plane. A resonant circuit is formed when the PCB ground plane and quarter-wave antenna work together. To make sure it doesn’t impact the total radiated power (TRP), the ground plane must be a quarter of the length of the wavelength. Lower frequency, longer wavelength bands need a longer ground plane. As a result, 5G antennas in devices for applications that use long wavelengths are typically larger than what was required for earlier cellular technologies.

Power consumption also impacts on device design, as power-hungry devices that can’t operate for long periods without recharging or replacement have limited use in many applications. A poorly-designed device will operate at low efficiency and have a shorter lifespan.

Antenna efficiency varies across frequencies. It’s a measure of the radiated power vs. the input power, expressed as a percentage. Ground plane length also impacts on efficiency and is more significant at lower frequencies. Low percentage efficiency antennas will consume more energy and reduce battery life.

Do all cellular devices have to use 5G?

5G is not intended to replace 4G, but work alongside it. Existing 4G infrastructure will remain, so new cellular devices do not automatically have to be 5G-enabled.

Though 5G delivers improvements to some core 4G LTE features, such as higher speeds and larger bandwidth, there are applications that will not benefit from transferring over to 5G because they do not require its benefits. Many of the Internet of Things (IoT) applications, such as sensors in petrochemical plants or consumer vending machines, do not need to transfer much data or transfer it very fast. However, they generally need a long battery life and good range. This makes 4G the best network for this type of application, as it has longer range and uses less energy than 5G.

There can be value in future-proofing mobile devices if the current performance expectation is low, but it may increase in future. An IoT monitoring device, such as a multi-sensor on a pipeline, may only measure daily flow rates when first installed because the back-end platform lacks the capability to monitor more complex data flows. And it may be monitoring thousands of sensors simultaneously across a network. Sending a single data set once every 24 hours to confirm operation is perfect for 4G.

The plan may be to upgrade the pipeline and its back-end monitoring and analytics platform to monitor flow in real-time, alongside temperature, humidity, vibration and other operational variables. Suddenly, the sensor is sending more data in real-time, and if the pipeline is supplying critical facilities, monitoring becomes mission critical and so needs access to 5G.

Does the designer specify 5G from the outset, even if not needed, or could there be another solution?

How to avoid over-specifying cellular devices for 5G

The core message to designers and engineers is not to be duped into thinking that all new mobile device designs should incorporate 5G network technology. Unnecessarily incorporating 5G compatibility into the design of an IoT sensor is over-specifying the device, changing its shape and causing issues for the wider application.

Most IoT devices are small, operate independently for long periods, and have low data volume and speed requirements. So why would they need the performance improvements offered by 5G when 4G already delivers what’s needed? Adding a 5G antenna for a device that will never use many of its frequencies could increase the size of the device.

Selecting fit-for-purpose antennas

Outlining the ground plane availability and clearance if needed, efficiency requirements, device size and frequency bands will help to narrow down antenna choice and determine which type of antenna is best for the application. Where ground plane requirements can’t be met, innovative off-PCB alternatives, such as flexible printed circuit (FPC) antennas, are a viable option.

Alternatively, the future-proof solution is our Allani antenna. This is smaller than 4G antennas, including the clearance area, yet it supports 5G. We can say it offers the best of 5G and 4G without enlarging the mobile device.

Antenova manufactures a wide range of antenna products to suit different devices and their applications. To see our full range of antennas for cellular devices – including 5G, 4G and 3G – browse our range of antennas or download our antenna comparison guide.

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