Industrial wireless sensor networking has had a tough row to hoe from the very beginning, despite the significant benefits it brings. Unfortunately, sizable barriers still prevent the technology from reaching its full potential.
Initially, the primary obstacles included reliability (particularly for process-critical applications and situations that required deterministic performance), throughput and link range limitations, battery shortcomings, and the absence of standards. Slowly, though, new technologies eliminated these barriers.
Mesh networking, with its self-healing algorithms and redundant pathways, and mobile ad-hoc networks, with their self-configuring flexibility, go a long way toward addressing reliability concerns. The development of multiple-input and multiple-output, or MIMO, enabled by its smart antenna technology, greatly improves data throughput and link range without additional bandwidth or transmit power. And through the efforts of IEEE and Bluetooth SIG, the 802.11 and Bluetooth standards have provided the framework needed to get wireless off the ground.
Wireless adoption has also been hindered by the perception that batteries provide a less-than-optimal power source. While battery makers have continued to improve their technology, the cost and nuisance of replacing these power sources has made some reluctant to shift to wireless. This is changing with the refinement of energy harvesting. And while the technology is not fully developed, it is advanced enough to be an alternative to batteries and to open the way for broader adoption of wireless.
So what's holding wireless back? Although there are a number of challenges, one thing comes to mind immediately: the competition between ISA 100.11a and WirelessHart over which standard will be the dominant enabler of smart instrumentation.
The two standards are very similar in intent and technology. Both standards aim to serve the same market, perform many of the same functions, implement IEEE 802.15.4 hardware, and use Device Description Files. The differences between the two, however, are enough to prevent end users from using the two technologies together. So the industrial community is back in the familiar position of having to choose one standard over the other. The result is that end users don't have the freedom to select best-of-class instruments from the full range of vendors. And choosing one over the other means investing in an uncertain future. In addition, until the standard war is resolved, many vendors will be reluctant to invest precious R&D money in one standard or another.
Why don't the two sides work out their differences? Each side has invested too much to give up its perceived advantage or market share. The champions on both sides have committed resources, won over vendors and end users, and created product certification processes. Just as important, each believes its standard is better than the other.
So where does that leave wireless? In a slugfest, where the real losers are the potential users and the vendors who produce products that would benefit from one standard. How will this end? Ask anyone who participated in the fieldbus wars.
Tom Kevan is a New Hampshire-based freelance writer specializing in technology.