Cellular carriers challenge mesh-network dominance.
Now that wireless carriers are promoting their networks as a cost-effective communications platform for smart grid data, they face legitimate questions about fundamental performance issues. But if public networks turn out to be the better choice in many cases, utilities might have some explaining to do before state commissions.
In the pantheon of annoying but effective TV advertising, Verizon Wireless’s “Can You Hear Me Now?” campaign has surely achieved immortality. By pointing out the most universal of mobile phone weaknesses—dead spots and drop-outs—Verizon cleverly moved out in front of the problem to position itself as the market’s coverage leader, much to the irritation of AT&T and the other major carriers.
But this marketing success highlighted cracks in the cellular mortar that have yet to be completely filled. The fact is, there’s no such thing as a perfect wireless phone network, and there never will be. Between the challenges of ground clutter, radio-frequency (RF) interference and technology gremlins, mobile phones will always suffer the occasional glitch.
Most callers have come to accept such imperfections as the price of affordable service—even if they gripe about it on general principles. However, now that wireless carriers are promoting their networks as a cost-effective communications platform for smart grid data, they face some nagging questions from utilities about performance issues like the ones Verizon parodied in its famous ad campaign.
And utilities aren’t just bitching on principle; we’re concerned about fundamental problems that, if unresolved, could leave people freezing in the dark.
But are those worries overblown? Is the real debate about market share and vested interests?
Technology vendor SmartSynch spent the past couple of years evangelizing the wireless smart grid, and bringing wireless carriers to the smart grid party. The company first arranged a new low-cost deal (i.e., 50 cents per meter, per month) with AT&T in March 2009, and during 2010 forged similar agreements with Verizon, Sprint, T-Mobile and other carriers. Since then, the company won contracts to install systems for TNMP, TVA, and the municipal utility in Memphis, Tenn.
So far, however, such deals have remained small—like 1,000 meters in the case of Memphis—partly because of lingering doubts about public wireless service. In July 2010 the Utilities Telecom Council summed up such doubts in its response to a DOE request for comments about the communications needs of the smart grid. The UTC said public wireless networks would play an increasing role in the industry, but that so far they are “not appropriate for mission critical communications because they lack sufficient reliability, geographic coverage and response speed (low latency).”
Since then, proponents of private networks have taken their cues from the UTC. Mesh-network provider Trilliant, for example, points out that its systems provide utilities with “full control of performance and [aren’t] reliant upon the policies and capabilities of a public carrier.” Others acknowledge the potential for public wireless to serve non-critical purposes, such as data backhaul for advanced metering infrastructure (AMI).
“Which choice is best depends on the utility use case,” said Narasimha Chari, chief technology officer with vendor Tropos Networks. “Going with a public carrier can be the fastest way to get an AMI project completed. But for distribution automation, cellular isn’t really an option. It doesn’t give you the low latency you need.”
SmartSynch and the wireless carriers, however, say such arguments are based on misconceptions and outdated information; that wireless networks have dramatically expanded their coverage in recent years, and nearly ubiquitous 2G data networks are perfectly capable of providing response rates below 800 milliseconds, as utilities say they need.
“We’ve spent millions of dollars testing the latency issue,” said SmartSynch Chief Marketing Officer Campbell McCool. “It’s easy to claim there’s a latency problem, but it’s absolutely incorrect. Latency is actually lower with cellular than it is with mesh networks.”
So the experience of the average cell phone user doesn’t accurately represent what public wireless networks can do for stationary utility systems, according to McCool. If mission-critical systems need things like low latency, guaranteed coverage and bandwidth priority, then public carriers can provide it under standardized service level agreements (SLA).
Will such SLAs explode the costs for utilities? The answer depends on whom you ask, but it’s fair to say that if they do, then public carriers won’t get the business. Utilities will board the cellular bus only if it makes more sense than building out their own mesh networks.
If it’s true that public wireless networks can provide the same level of service that mesh networks can deliver, then cost becomes the only question that really matters. Technology aside, the basic difference between the two platforms is that in most cases a private network is owned by the utility as a capital asset—usually subject to base-rate financial returns—while public network service represents an operating expense. Building a network is a much larger capital cost, but over time cellular service costs add up.
“It’s definitely a cost utilities aren’t paying today,” said Mark Munday, president and CEO of metering company Elster Solutions N.A., which designs its systems to be network-agnostic; Elster sells meters that operate on mesh networks, and also it signed an agreement in mid-December to integrate AT&T connectivity into its AMI products. “Utilities that already have private networks in place want to leverage that asset rather than adding a monthly charge. That makes sense, but sometimes private radio is narrowband and you need more bandwidth. We believe in matching the right technology to the applications and preferences of the utility.”
Only experience can prove whether public cellular networks are the right technology for mission-critical utility applications, as SmartSynch and the wireless carriers say they are. Time is running short, however, because once utilities build out mesh networks to transport their smart grid data, cellular might be locked out.
“We’re all trying to capture the market,” McCool said. “There’s no question about that. And utilities that have spent tens of millions of ratepayer dollars to start building out an RF mesh network aren’t going to suddenly stop and say, ‘Hey, maybe we made the wrong decisions.’”
However, if public networks turn out to be the better choice in many cases, utilities might have some explaining to do before state commissions. “Can you hear me now?” certainly wore thin as a TV commercial, and someday it might prove to be an imprudent reason for building private networks.