Smaller cells could do the same job, but for all phones, not just Wi-Fi enabled ones like the iPhone. They could also carry calls as well as data.
San Diego-based Qualcomm will be at the Barcelona show with a live demonstration of how "heterogeneous networks" — ones that mix big and small cells, can work. A key issue is minimizing radio interference between the two types of cells. Another hurdle is connecting the smaller cells to the bigger network through optical fiber or other high-capacity connections.
"That's an impediment that we're seeing many operators struggling with right now as data volumes have increased," Hays said.
LM Ericsson AB, the Swedish company that's the largest maker of wireless network equipment in the world, is also introducing a more compact antenna at the show, one it calls "the first stepping stone towards a heterogeneous network."
Small cellular base stations have already penetrated hundreds of thousands of U.S. homes. Phone companies like AT&T, Verizon Wireless and Sprint Nextel Corp. have for several years been selling "femtocells," which are about the size of a Wi-Fi router and connect to the phone company's network through a home broadband connection.
The cells project radio signals that cover a room or two, providing five bars of coverage where there might otherwise be none.
British femtocell maker Ubiquisys Ltd. will be in Barcelona to demonstrate the smallest cell yet. It's the size of a thumb and plugs into a computer's USB drive. According to Ubiquisys, the idea is that overseas travellers will plug it into their Internet-connected laptops to make calls as if they were on their home network, but there are potential problems with interference if used that way.
According to Rupert Baines, marketing head of Picochip Ltd., a more realistic application for a tiny plug-in cell is to make it work with cable boxes or Internet routers, to convert them into femtocells.
A key part of the "small cell" idea is to take femtocells outside the home, into larger buildings and even outdoors.
Picochip, a British company that's the dominant maker of chips for femtocells, will be in Barcelona to talk about its chips for "public-access" femtocells, designed to serve up to 64 phone calls at a time, with a range of more than a mile. They could be used not just to ease wireless congestion in urban areas, but to fill in dead spots on the map, Baines said.
For instance, a single femtocell could provide wireless service to a remote village, as long as there's some way to connect it to the wider network, perhaps via satellite.
Analyst Francis Sideco of research firm iSuppli pointed out a surprising consumer benefit of smaller cells: better battery life in phones.
When a lot of phones talk to the same tower, they all have to "shout" to make themselves heard, using more energy. With a smaller cell, phones can lower their "voices," much like group of people moving from a noisy ballroom to a smaller, quieter room.
"Ultimately, what you end up with is a cleaner signal, with less power," Sideco said.