Wireless Woes and Wows

As we are preparing to begin deployment of a handful of updates to our product line in the general area of the ZIgbee wireless device networking support, I have had a moment to reflect on our journey with wireless device networks over the past couple of years.

There can be little doubt that our product is dependent upon wireless device networking  technologies. By far the largest number of installed sites, whether they be commercial buildings (restaurants, convenience stores, etc.)  or residences, are preexisting structures where running new wiring is simply cost prohibitive.  This reality simply mandates the use of some type of wireless device networking technology. Having had previous experience with power- line based technologies, we quickly discounted this approach due to transformer coupling issues that are present in nearly all small commercial buildings. This left radio frequency technologies and, again due to past experience, we selected Z-Wave as the basis for our initial EcoView product offering.

Z-Wave is a very robust and mature wireless mesh networking technology popular in home automation products. Very early on in our field installation experience, however, we found that the relatively low power output of the Z-Wave radios caused numerous issues for us. This was particularly true in restaurants where it is common to find a lot of stainless steel and other obstructions that often result in signal attenuation and loss of information.  Nevertheless, we managed to install quite a few commercial facilities using Z-Wave and many of them still operate perfectly today (some have been switched to Zigbee).

This time last year (2009) we decided to try Zigbee radios to see if we would get any better performance in the field. We were attracted by the variety of Zigbee chipset vendors with competing features such as radio power choices and packaging options.  Early tests showed that the additional radio power alone warranted seriously considering making the switch. In May of last year (2009) we launched the first version of our EcoView product utilizing Zigbee radios.  This is where the fun started. We spent the next few months learning, painfully, about all of the Zigbee communication stack nuances and quirks and how they could come into play in real-world environments.

Particularly troublesome was the apparent tendency for the Zigbee wireless network to spontaneously decommission itself (nodes drop off).  While this feature may be potentially interesting in some scenarios, such as where a device can physically move about, it was a real headache for stationary networks where sources of attenuation move instead, such as in commercial kitchens.  This sort of issue was compounded by the fact that we currently purchase our HVAC thermostats from a private label vendor, who themselves struggled initially with the same wireless behaviors. Luckily, the initial trial-by-fire experience has smoothed out as our knowledge of the technology and its behaviors has matured.  Sitting here now from the position of having several hundred installed sites working, it is clear to me that our product base is overall much better off for the move to Zigbee radios.