Testing solutions

5 mins read

Martin Varga, Wireless and Custom Engineering Team Leader, Anritsu talks to Neil Tyler about the challenges associated with testing IoT devices.

Over the past few years intelligent connectivity has proliferated and the Internet of Things is seen as helping to accelerate the drive towards greater business insights boosted by the growing deployment of applications and the use of sensor-driven analytics.

Artificial intelligence models and edge computing architectures are being used across a wide group of sectors, linking IoT networks to the Cloud and providers such as Amazon Web Services and Azure are helping to reduce the cost of implementing edge-driven IoT.

The growth in users and the insights derived from the IoT are now extending into a whole new range of applications from the factory floor to better understanding and protecting the environment around us.

As this trend accelerates so companies will produce more IoT devices and, as they do so, they will need additional tools to test them. The growing impact of 5G on IoT technology is also expected to trigger an unprecedented growth in test & measurement.

When it comes to the IoT, network connectivity comprises of four core layers: the physical layer (sensors and controllers); network layer (gateways and communication units); data management layer (local or cloud services at the backend), and the application layer (software for user interaction), so it’ll be critical for devices to be able to exchange sensitive information easily before entering the market, so testing tools will be required to spot any defect in IoT devices. 

So, IoT testing is vital if companies are to validate the performance, reduce the security issues, and boost the functionality of their IoT devices.

The complexity and variability of IoT testing makes planning crucial when it comes to testing and a thorough testing process is recommended to ensure a quality IoT product and high customer satisfaction.

So, what are the issues confronting companies when it comes to IoT testing – is it the number of IoT platforms, the communications protocols, or security?

Addressing the testing issues

According to Martin Varga, Wireless and Custom Engineering Team Leader, Anritsu, “The IoT itself brings not just one communication technology but multiple technologies such as cellular (LTE, 5G) and short- range wireless technologies (WLAN, Bluetooth). Naturally, an IoT device must support both in order to provide various services and hence the major challenge when it comes to IoT testing is to test various aspects of each communication technology.

“Besides multiple communication technologies there is also the challenge of testing various layers in an IoT device. Where testing is focused on the physical layer of communication technology the aim is to ensure trouble-free connectivity; application layer testing is important to identify issues around the user-experience or to correct the functionality of services which IoT devices offer,” explained Varga.

When it comes to testing developers often think IoT technologies are already mature and are designed to provide trouble-free connectivity and communication.

According to Varga, while that may be true, “Each IoT device will have a unique design and deploy components differently. These will naturally influence each other and may also interfere with each other, so unless the IoT device is properly tested, you will never know how the design and the components used in a device work whatever the maturity of the technology.”

Varga also made the point that many developers think that testing is complicated, complex and expensive which he suggested was not the case.

“There are plenty of test and measurement systems that are able to provide easy, effective and cost balanced solutions which at the end of the day will save costs in the IoT device design process.”

There are certainly a wide range of issues that need to be considered when it comes to testing for the IoT, from RF design testing under specified conditions to performance measurements, such as power consumption and battery life, as well as compliance with applicable regulatory standards and operator-specific requirements before wireless devices can enter the market.

So, what makes for a good IoT test strategy?

“Simply put, a good IoT test strategy is just to have one,” Varga suggested. “That means you need to implement concrete testing and measurement in each phase of the IoT device’s design and development cycle. To develop an IoT device without any testing and measurement during the development cycle may result in costly mistakes with a device that does not work as expected or one that provides only partial or no service to the end user.”

Varga also made the point that it is important to differentiate between development IoT testing and production testing.

“The key difference is in the speed of measurement. IoT testing in the development phase usually requires full simulation of the network and involves the protocol stack for signalling which requires time to establish communication links for measurement.

“Manufacturing testing ensures products are of the highest quality, but this requires fast and accurate measurement hence production line testing does not involve protocol stack and signalling to establish an active communication link between IoT devices and the test instrument.

“Production line test works purely in the non-signalling mode where devices either transmit certain waveform signals and the test instrument measures it, or the test instrument transmits certain waveform signals and the IoT device measures the received signal.”

IoT test equipment can be categorised as cellular test equipment supporting cellular technologies like 5G, 4G, 3G and 2G and short range wireless equipment that supports technologies like Wi-Fi and Bluetooth, explained Varga.

“This type of equipment usually serves as a network or device simulator to test the IoT device to correct measurement states using protocol stack signalling and perform measurements.

“Such an operation naturally requires the setting of various parameters which makes measurement more complex, however on the other side measurements are done in real life conditions making sure that IoT devices will work correctly in commercial deployment and use. Another type of test equipment is focused on non-signalling testing where only the physical layer is tested without engagement with the higher layers of the protocol or application. Such measurements give less complex parametrisation and fast speed of measurements, although they are measuring only a limited part of the whole IoT device and so could leave some nasty surprises in terms of performance and operation once the IoT device is deployed and is use,” Varga warned.

The best types of IoT test equipment should offer multiple measurement types such as RF or/and application type measurements, according to Varga.

“It also should offer enough accuracy and quality in signal generation and analyses to accurately measure the performance of an IoT device,” said Varga. “Easy parametrisation and intuitive operation are also important factors. IoT test equipment needs to offer effective simulation and measurement capabilities where the developer has an environment under full control, which will enable them to verify and measure expected behaviour and performance through the whole development cycle so there are no delays caused by having to re-design or fix design faults.

“Pre-compliance testing before going to full certification will save time and money and accelerate the commercial launch of an IoT device.”

According to Varga, set up time is important in production line testing where speed of measurement is critical as well as capacity, due to the high number of devices that will be manufactured. He suggested that allowing parallel testing of multiple devices simultaneously would increase capacity and overall production line volume.

“Anritsu is able to offer multi-technology high volume production line test solutions allowing parallel testing of multiple devices with high levels of accuracy, but we are also able to offer other test and measurement solutions for cellular and short range wireless IoT devices, whether used in prototyping, design or development.

“Our solutions come with unique functions and are both easy and quick to set up, delivering effective and complex measurements.”

Critically, it’s important that companies like Anritsu understand the needs of engineers and developers who perform or require various types of measurement.

“The technology itself, whether it is cellular or short-range wireless, brings a certain level of complexity in terms of the measurement environment setup. Therefore, engineers need test equipment that is easy, intuitive, and provides a stable measurement setup to bridge the complexity of the technology and to deliver better and more understandable test results.

“While Anritsu is a test and measurement company it is also, and has to be, a partner for all its customers.”