Network planning issues are some of the more difficult challenges mobile operators face when it comes to deploying public access small cells.

Those potential problems, and their implications for operators, were discussed at a media briefing hosted by the Small Cell Forum Ltd. on Monday in London. (See Small Cells Throw Up Big Challenges for Operators.)

Basically, planning a small cell network is fundamentally different from mapping out a traditional macro cell network, and therein lies the challenge. Public access small cells are likely to be deployed for adding capacity in high-traffic areas, rather than for coverage like macro cells. And when it's a large deployment, certain things -- site selection, site acquisition, supplying the site with power, installing the small access points and having the right tools to analyze network traffic in order to determine where a small cell would be needed in the first place -- all become more difficult, adding time and money to the network planning process operators are used to with their macro 3G or LTE networks.

Telefónica UK Ltd. discovered all this when it rolled out Wi-Fi access points from Ruckus Wireless Inc. , which went live last week, on lampposts in central London. It's a Wi-Fi small cell network, rather than 3G or LTE cellular, but the planning issues are similar.

According to Robert Joyce, chief radio engineer for Telefonica in the U.K., getting backhaul transmission and a power supply to the access points was the biggest challenge for the network rollout.

But even attaching the access points to the lampposts proved to be an interesting procedure. In London's council of Westminster, the only people allowed to install anything on a lamppost are the folks who hang the Christmas lights each year, he explained. Also, only one additional fuse box is allowed to be installed for powering the access point, which means each lamppost is able to take just one access point from one operator.

"A lamppost installation is not cost-effective," said Joyce, adding that the deployment cost thousands of pounds per lamppost. "Ideally, I want to spend less than £1,000 [per lamppost]."

If mobile operators have to navigate such complex and idiosyncratic local authority rules about how lampposts, or other public assets, can or can't be used in a small cell rollout, then some say a different deployment model is needed from the outset -- such as network sharing.

"Operators must absolutely share small cell infrastructure," said Rob Reagan, president and founder of Public Wireless Inc. . "I think a neutral host is the missing piece of the puzzle in the small cell ecosystem."

New operator business models are already starting to emerge, according to David Swift, marketing director at Alcatel-Lucent (NYSE: ALU). In certain cities in Asia/Pac countries, a few consortia have cropped up offering a wholesale small cell service, he said.

New business models, overcoming network planning and other issues are bound to be just some of the subjects discussed and debated at the Small Cells World Summit, which kicks off in London on Tuesday.

--Michelle Donegan, European Editor, Light Reading Mobile