DAS: The Technology You’ve Never Heard of Enables the Wireless Campus

• By Walt Magnussen
• 09/08/10

Spurred by students’ voracious appetites for smartphones and broadband mobile devices, demand for wireless service and bandwidth-intensive mobile applications has grown dramatically at Texas A&M University. Faced with this challenge, the university had two alternatives: deploy new microcell sites for each operator, or deploy a shared network of Distributed Antenna Systems (DAS). Texas A&M’s solution provides a glimpse into the communications challenges that many universities face today. [Above: A DAS antenna sits unobtrusively atop a light pole.]

At Texas A&M University, the networking infrastructure for our campus-wide communications has to be more resilient today than perhaps at any time in the past. This is due to a confluence of factors, including a dramatic reduction in use of high-cost landline telephones in dorms, a growing concentration of smartphones in the student population, and the expectation of limitless bandwidth for the variety of new smartphone-based applications in demand by students, faculty, and staff.

Meeting such demand in the modern university has always been a matter of deploying the right technology and ensuring that it will “scale up” with increases in demand. That’s the situation we faced at Texas A&M as the basic “wired” telephone system, with unused phone jacks in every dorm room, became too costly to maintain, and too underpowered to meet the needs of always-on students. Cellular technology attacks the problem, providing service for smartphones, but so-called dead zones limit its use in environments that are out of the reach of a cellular tower.

At Texas A&M, the challenge was two-fold: how to accommodate the requirements for scalable bandwidth by the campus population, and how to equip our sports venues--the 90,000-seat Kyle stadium, for example--to provide wireless coverage and bandwidth for a sellout crowd.

Why DAS? Why Now?

Initially, the university supplemented cellular coverage with the addition of macrocells and microcells in select locations across campus. However, we realized that this approach could lead to a rather complex networking environment. The university’s facilities manager, for example, would have to approve the placement of every microcell and macrocell, and the legal department would have to draw up a contract for each cell site addition. Making matters worse, these requirements would be replicated for each operator serving the campus.

A second factor arose: With the near-universal adoption of smartphones by today’s university students, macrocells and microcells would, at some point, reach a limitation in their ability to deliver the necessary bandwidth to support those smartphones, both indoors and outdoors.

That’s where an optical fiber-fed distributed antenna system, or DAS, entered the picture. DAS involves the strategic placement of unobtrusive, low-profile antennas connected back to a central location via fiber strands. Each DAS site is shared by multiple wireless operators, substantially reducing the number of sites needed on campus. DAS can be installed to meet current needs and the fiber transport easily scales up as demand grows. Best of all, deploying fiber-fed DAS across the campus requires only a single contract with a DAS provider if that is the way you choose to deploy it.

As technology goes, what’s here today won’t always work tomorrow, but DAS technology defies that rule: DAS is what wireless network managers call device- and protocol-agnostic, which means that it doesn’t “care” what new communications protocols are introduced on the network, or what new user devices, such as smartphones and wireless eBook devices, become popular. DAS simply carries, over the fiber, the traffic that it’s given. Nirvana among network managers means “future-proofing” their networks, and although that term doesn’t always represent reality, it’s fair to say that fiber-fed DAS “future-proofs” the university for any conceivable technology developments in wireless communications.

The DAS Plan

While expanded bandwidth and coverage demands provided the incentive to adopt DAS at Texas A&M, what sped up deployment was the university’s mandate that we select and deploy our technology of choice before decommissioning the under-utilized landline phones across campus. Our first move was to survey students about the level of lost mobile connections they were experiencing. We found the best record with two national carriers and elected to work initially with them, using new DAS sites to extend coverage on their networks.

With carriers already on the campus, the process of placing DAS sites became routine. Since the carriers’ central transmission equipment was already housed in the same general location, our DAS provider, NextG Networks, simply specified where the university should build out fiber, and we would then utilize the new and existing fiber, identifying strategic sites for the placement of new antennas. Each DAS site could then go live after it was installed, providing quick relief for students who either had no reliable wireless signal or lacked the bandwidth they needed. Each DAS site already supports two operators, eliminating the campus clutter that would result if each operator had its own network of cell sites. The system is designed to add operators as they sign on.

Today, DAS spans the campus, and we’ve met our goal of providing broad coverage throughout the residence halls. In the last one-and-a-half years, we’ve deployed approximately 50 sites across campus. And we currently have new sites under consideration. All of this was accomplished by the strategic placement of outdoor DAS sites, in coordination with a single vendor and a single point of contact, yet servicing multiple wireless operators.

Is DAS Really Future-Proof?

A benefit that DAS brings to any university with a football stadium is the ability to “reallocate bandwidth capacity” to handle a massive increase in bandwidth demand and serve thousands of smartphone-toting fans. It’s not uncommon today to see a football fan watch another game on his smartphone while attending our game in person. Other fans will blog, send e-mail, and update their social network page while watching the game.

Still, universities have to look beyond the immediate demand. Today’s communications protocols are known as 2G or 3G (second or third generation). But newer 4G technologies are now being deployed, and they’ll provide bandwidth increases on the network to double bandwidth--and then double it again as required--to meet ever-greater needs for network capacity.

Here’s the crux of the matter: While these technology advancements will speed up communications fairly dramatically, they are compatible with the DAS network that extends their “reach” to the four corners of the campus. As a reminder, DAS is device- and protocol-agnostic. Throw 3G or 4G at it, and it blithely transmits over the fiber whatever it’s given. You could call that future-proof.

What’s Next?

At Texas A&M, we’re in a good spot to deploy 4G technologies. We’re in talks now with carriers who are planning to introduce new 4G services. When that happens, these carriers will be able to install new 4G equipment cabinets in the same locations as their existing equipment cabinets, connect them to our existing DAS fiber network, and extend 4G technology across campus in a very short space of time using the same fiber. Furthermore, the capital costs to upgrade will be minimal.

DAS is truly an enabling technology. I feel confident that universities using DAS today will be among the first to team up with wireless providers to roll out 4G technology and, by so doing, improve the academic experience for all. With the number of DAS sites we have on campus, I’d venture to say that Texas A&M University is among the top two to three percent of American universities in wireless coverage, and we’re 4G-ready.

With the elimination of landline phones and the reduction in the number of individual-operator microcell sites, DAS provides ample traffic capacity, with room to meet the inevitable traffic demand for 4G. Those voracious smartphone-loving Aggie students won’t go “wireless hungry” at Texas A&M; we will be able to feed them all of the coverage and capacity they want and need thanks to the DAS network they’ve never heard about.