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Hetnet evolution: Network providers combine DAS and small cells

Network providers are combining technologies as they add multiple operators to their systems. Carriers are bringing their solutions of choice to the network, and providers are finding ways to accommodate them.

In Atlanta, Crown Castle is in the process of building 459 nodes to support one carrier, using remote radio heads. A second carrier will also be joining the DAS, but this one will use lower power small cell units that include baseband processing as well as the radio and the antenna.

Crown Castle’s Mike Kavanagh, the company’s president for distributed antenna systems, said that the key to supporting multiple carriers and different technologies is a high quality fiber backbone. He said that Crown Castle significantly increased its fiber footprint in Atlanta through its acquisition of Sunesys, and is able to offer operators a “turnkey” solution. Crown negotiates access to the public rights of way on behalf of the carriers, and pays the required fees to the Atlanta city government and the local utilities. Carriers then pay Crown Castle for access to the system. Crown Castle is acting as a “neutral host” provider, leasing space on a DAS in much the same way it leases space on cell towers.

In Central Texas, ExteNet Systems is the neutral host provider for a distributed network that supports Verizon Wireless and AT&T at Circuit of the Americas race track, the only certified Formula 1 track in the US. The 1,500-acre facility is also hosts non-F1 car racing, motorcycle racing, X games and concerts.

“Given the high concentration of traffic within the facility, we continue to invest in our neutral host distributed network that enables robust cellular coverage and capacity across the 1,500-acre property for two national wireless carriers today,” said Jon Davis, VP for indoor networks at ExteNet.

ExteNet designed the COTA network to support four carriers. Verizon, the anchor carrier, went live in late 2012 and AT&T went live in 2013. The network is a hybrid of distributed antennas and remote radio heads. DeltaNode supplied the DAS equipment and Ericsson and Alcatel-Lucent supplied the remote radio units.

Hybrid networks indoors
Indoors, operators are starting to use small cells with baseband processors as signaling sources for distributed antenna systems. These can make for a much more efficient headend.

“A signal source in the past has been a rack full of equipment because they had to use a macro base station in order to have software that would be compatible with the rest of the macro network outdoors,” said analyst Joe Madden, founder of Mobile Experts. “The signal source often puts out 80 watts of RF power, which is way too much to feed into a DAS, so they attenuate that power down to less than a watt so they can feed it into a DAS and then distribute it through the building and re-amplify it. It’s been really wasteful. So the new trend now is instead of doing one of those big macro station cabinets as a signal source they can use a small cell … with a low power output to feed into that DAS system and then support one sector of the DAS. And now instead of the big rack you’ve got a little box and you might be able to stack up six or seven of them in the same space.”

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Martha DeGrasse
Martha DeGrasse
Martha DeGrasse is the publisher of Network Builder Reports ( At RCR, Martha authored more than 20 in-depth feature reports and more than 2,400 news articles. She also created the Mobile Minute and the 5 Things to Know Today series. Prior to joining RCR Wireless News, Martha produced business and technology news for CNN and Dow Jones in New York and managed the online editorial group at Hoover’s Online before taking a number of years off to be at home when her children were young. Martha is the board president of Austin's Trinity Center and is a member of the Women's Wireless Leadership Forum.

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