DAS Crazy: Distributed Antennae Systems Hit the Big Time

By Paula Bernier, Executive Editor, TMC  |  June 17, 2014

Small cell solutions have grabbed headlines in recent years for their ability to add capacity and indoor coverage to cellular networks. But while these offerings have gotten off to a slow start, DAS continues to make gains in large indoor environments including high-end malls like Galleria Dallas, high-rise office and residential spaces, hospitals, and sports arenas.

"As we anticipated, the great small cell ramp did not happen in 2013 as many in the industry had hoped. Testing activity remained solid, but actual deployments were modest. Small cell revenue was just $771 million last year, a sharp contrast to the $24 billion 2G/3G RAN market," reports Stéphane Téral, principal analyst for mobile infrastructure and carrier economics at Infonetics Research.

ABI Research (News - Alert), meanwhile, says that the in-building market continues to grow, with DAS equipment revenues up by more than 10 percent year over year and almost $1.4 billion being spent on in-building coverage in 2013.

While small cells and Wi-Fi have their place and grab a lot of headlines, at the end of the day if you are holding a big event for which you need communications to operate smoothly, DAS is the answer, says Téral.

“The Super Bowl could’ve never happened without DAS,” opines Téral.

Perhaps. In any case, some folks are now referring to DAS as the fourth utility (with water, gas, and electricity as the other three).

Sizing Up the Market

At the moment, DAS is a $2 billion worldwide market, and that’s despite the big drop in investment for this kind of infrastructure in China, where DAS upgrades were just recently completed, says Téral. But the $2 billion just represents the hardware piece, he adds, the related engineering and support services are worth another $5 billion.

DAS hardware vendors, many of which also have professional services practices, include industry leaders Corning (News - Alert) Mobile Access, CommScope, and TE Connectivity, as well as Axell Wireless, Comba (out of Hong Kong), Ericsson, Kathrein-Werke, NSN, Optiway, PowerWave Technologies, Solid, and Zinwave. And AT&T, one of the world’s largest cellular services providers, has a large and growing DAS practice.

Typical DAS solutions consist of an existing macro base station that sits somewhere within the venue; that connects to a DAS hub that propagates and/or converts, processes or controls the communication signals transmitted and received through the DAS nodes, each including at least one antenna for the transmission and reception of a wireless service provider’s RF signals and one remote radio head; and on-site fiber is used to distribute signals to remote radios heads throughout the defined area.

The Goodness of DAS

These solutions are purchased both by cellular service providers, and by large businesses and other operations. At $50 million to $200 million per project, DAS isn’t cheap, says Téral, but it offers a load of capacity, and can be a lot less complicated than setting up a network using a bunch of small cells.

“There is nothing else today that can blast so much capacity in one shot,” explains Téral.

That’s what AT&T and its customers like about DAS, says Chad Townes, vice president of antenna solutions at the service provider. AT&T has done DAS deployments in various environments including airports, convention centers, high rises (including New York’s iconic Rockefeller Center), and stadiums.

DAS allows AT&T to hit the capacity demands people have with the speeds they expect, Townes says. He adds that DAS is good for large-scale venues whereas small cells (at least today) are better for “small rifle shot” applications, and that AT&T is leveraging both technologies where appropriate. DAS is also attractive because it enables a neutral host model, in which multiple cellular carriers can share the infrastructure (a good thing for venue owners such as stadiums), and because it can carry all frequencies.

AT&T treats DAS as any other node in its network, so customers have the same experience whether they’re on cellular or DAS infrastructure, says Townes. Some companies use repeaters in their DAS deployments, adds Townes, but AT&T doesn’t because repeaters just boost signal strength but they don’t add capacity.

Townes says AT&T views DAS a being critically important to its success. His team of 1,000 employees, which was established about four years ago, does about 1,000 3G and LTE DAS deployments a year. Last year, he adds, AT&T spent seven to eight times the capital on DAS that it spent just three years ago.

Axell Wireless, which ABI Research says is one of the most innovative companies in the DAS equipment space and is No. 3 in worldwide DAS market share, provides its equipment to more than 170 service providers around the world, including T-Mobile (News - Alert), Verizon Wireless, and Vodafone, says Matt Thompson, vice president of sales for the Americas at Axell Wireless.

Eighty of world’s largest subway systems have deployed DAS networks with the Axell gear, which is now being used to build out a DAS solution in the Paris Metro. Axell powers the DAS network in the Chunnel, a train route connecting London and Paris. Its gear is in some of the world’s large buildings, including Dubai’s Burj Khalifa, the Department of Homeland Security campus, the Pentagon, and the World Cup stadiums in Brazil. Axell gear was used in indoor and outdoor environments in the 2012 Olympics. It’s also used in pipeline deployments, as well as in public safety applications, a space in which Axell claims No. 1 DAS market share.

Small cells today generally only support a single band and a single operator, whereas, as noted above, DAS solutions can work on all frequencies and enable multiple carriers to come aboard.

The BYOD phenomenon, and the fact that around 80 percent of mobile data traffic is streamed indoors, also are contributing to the success of DAS, says Thompson. As noted above, cellular companies are active users of DAS. But because the BYOD craze can dilute the number of subscribers each service provider has with a company, the service provider might not think the number of subscribers in a particular location warrants a DAS build, he says. In that case, the company itself may want to make an investment in DAS.

The Latest Thing

Téral of Infonetics sees big buildings in tier one cities like Chicago, Los Angeles, New York City, and San Francisco being the next frontier for DAS and what he considers DAS-like solutions.

DAS vendors are adding Wi-Fi and small cell capabilities to their systems to capture share in this area and others, says Téral. Meanwhile, solutions like AtomCel from Huawei (News - Alert), Cube from Alcatel-Lucent, and Radio Dot from Ericsson, which Téral says is based on the same basic architecture as DAS, are going after some of the same opportunities.

“We are going into a mixed up jungle, and they are all going into the untapped market,” Téral says.

In a jungle environment, only the strongest survive, and Axell believes its product, which Thompson calls the first point-to-point DAS solution, is giving it an edge over the competitor. He says the solution works in a similar way to a Cisco routing system, by going through a centralized hub and being able to send packetized data to any remote in the system. That’s beneficial, he says, because it opens the door to capacity shifting.

Typically, DAS solutions are designed to support the heaviest traffic load expected, but the Axell solution allows the base stations to shift capacity between the buildings they service, so if one location in a multi-building deployment has more capacity needs on a given day, it can shift more capacity in that direction, Thompson explains, adding that other DAS solutions tend to use a simulcast model. Capacity shifting creates savings for the DAS system owner because it means fewer base stations are needed, says Thompson, who adds that DAS base stations typically cost between $50,00 and $150,000 each.

Axell’s DAS solution is also futureproof, he says, because if you want to add another sector/base station, and assign some remotes to that new base station, you don’t have to rewire as you do with some DAS solutions. Instead, he says, you can make the change using the Axell software.

Although Ericsson has been pushing its Radio Dot solution – which is in trials with several large cellular carriers including AT&T and Verizon, and several abroad, and which will begin shipping later this year, Ericsson Networks Head Johan Wibergh (News - Alert) in a recent interview with INTERNET TELEPHONY said Ericsson offers a DAS solution as well and called DAS a well proven technology that is applicable to certain types of buildings. About 100 buildings in Manhattan are now served by DAS, he said, but he added that Radio Dot is much more cost competitive and easier to install. 

Edited by Stefania Viscusi