Can Wireless Devices Avoid Failures in a Crowded License-free Spectrum?

By TMCnet Special Guest
Gary Sorkin
  |  September 03, 2013

All sorts of devices – from baby monitors to building security systems – operate in the license-free spectrum of 900mHz and 2.4gHz, and the space is getting increasingly crowded. Every device has to hold its own among the conflicting radio waves from other products. It also needs to adapt to real-life conditions, such as keeping its signal strength through brick or wooden building walls, snow and rain, and a truck parked in its pathway. Even a properly operating device can be a subject to a cyber-attack, so command and control communications need to be adequately secured.

Many such problems can be eliminated right off the bat– enhancing the end user experience and saving manufacturers and system aggregators significant costs – if the devices are tested to help prevent failures.

Are Must-Haves Enough?

A testing laboratory starts with detailed device testing for adherence to specifications. These vary and may include Zig-Bee, Wi-Fi, Wi-SUN or Wi-Gig as well as requirements mandated by the Federal Communications Commission. Some manufacturers and system integrators believe that after their products have passed the required specification tests, they are ready to go for the domestic market. This belief often ends up costing them dearly when criticism comes from the retailers, installers and customers about the product’s functionality failures.

Does It Work as Designed?

Knowing that the device under test performs to the specified communication is of primary concern, but knowing that the command sent to the device is acted upon fully and precisely is of equal importance. While actual functionality of devices is not examined during product certification, such testing is highly advised. For example, if a thermostat is told to raise the temperature four degrees, functionality testing checks to see that it does, in fact, raise the temperature precisely four degrees.

After a device passes functionality testing, a user can trust his or her in-home consumption graphs and the thermostat displays. When functionality issues are uncovered during testing, fixing them before products reach the consumer saves manufacturers millions of dollars in lost revenue.

Playing Well Together on the Network

While manufacturers have control over their product design, the real-world benefit of their devices stems from their ability to interoperate with other products on the network. To test how well various devices play with each other, laboratory personnel tests various products generally known to communicate with the tested device within specified application clusters to exercise a series of commands. For example, to test a device that allows a homeowner to set a thermostat from an iPhone (News - Alert), laboratory personnel buys two copies of every brand of thermostat on the market and evaluates how the device in question interacts with them, simulating real-world conditions.  

Testing to environmental conditions is critical because rain and snow affect the limited

distance radio signals, as does the EMI crowding of the bandwidth due to other devices sharing the frequencies. Even a car parked in the way of the signal, and whether the house walls are made of brick or wood, might impact the performance of such low-power devices. The more testing is done for interoperability, the more knowledge is gained, mitigating the risks associated with problems in the field.

A New Level of Security

After the device progresses through interoperability testing, some laboratories now have the capability to use a suite of cyber fuzzing and penetration attacks to establish benchmarks of hardening to adhere to various cyber-security threat levels, regulated by the emerging cyber-security maturity modeling. A typical test would involve trying to penetrate the network with false information to check how resistant it is. Giving the customer a peace of mind that smart technologies are not going to become weak security points in the home or workplace is essential for the growth of every company and the entire industry.

While testing beyond specification for functionality, interoperability and cyber-security might seem a significant investment, it has paid off for many brands in lower deployment costs and increased customer satisfaction. A comprehensive suite of product tests also helps companies attain credibility and enhance their reputation

Gary Sorkin (News - Alert) has a combination of project management, business development, sales, consulting and technical engineering skills. Most recently he served as the smart grid business development contractor with TUV Rheinland of North America, a global testing facility for many standards and alliances including UL, FCC (News - Alert), Wi-Fi, ZigBee, ANSI and others. 

Edited by Stefania Viscusi