Network Paradox Part III: The incredibly shrinking cellular network
In Part I and Part II of this series, we established how cell sizes will have to shrink to meet data capacity demands. In Part III we examine just what those small cells will look like
See Part 1 of the Network Paradox, Mobile Data Demand by the Numbers, and Part 2, Meeting the Mobile Data Demand. All three stories are part of Connected Planet’s Mobile Data Paradox interactive feature and microsite.
There’s no question about it: If the mobile broadband network is going to support the enormous traffic loads the industry is anticipating, it will have to shrink. In order to scale traffic loads upwards, the size of cells have to scale downwards. Even with more efficient technologies and gobs of new spectrum, re-use of the current frequencies will be a major component of meeting mobile demand in the future. And while no carrier, vendor or regulator will argue that point, there’s little consensus over what those small cell architectures will like and when they must be implemented.
Small cells aren’t exactly a new concept for the wireless industry. Operators have been drawing in their cell radii since the advent of analog systems. As higher frequency bands have come online, operators have been forced to build tighter clusters of cells to deal with those frequencies’ lower propagation characteristics. As penetration has increased in urban areas, more towers have gone up to meet the needs for capacity as well as the need for coverage. Operators have dabbled in microcell and picocell architectures, deployed remoter radio heads and distributed antenna systems.
Ultimately, though, the macro cellular topology of wireless networks has remained unchanged. Spot coverage aside, the typical wireless network remains a collection of large microcells transmitting from towers and rooftops. That topology will have to change. The macro-cellular network won’t disappear, but industry experts believe it will become an umbrella coverage network, under which hundreds of thousands of much smaller cells will carry the burden of the mobile data explosion.
Just how small will those cells be? If technology and cost were not a factor and operators did nothing to curb the ever increasing consumer and enterprise hunger for bandwidth, there really isn’t a limit, said Rupert Baines, vice president of marketing for PicoChip.
“The logical endpoint is that the cell should be the size of a person,” Baines said. “Everyone should have their own bubble of coverage. We’re obviously looking at something more pragmatic.”
PicoChip’s more pragmatic approach is taking an already common home coverage solution, the femtocell, and optimizing it for the wide area network. Femtocells today are essentially private network coverage solutions. They use an operator’s spectrum, but they connect to the network via a customer’s broadband line. They only support a few connections at one time, and only pre-authorized devices can access them. That hardly seems the ideal platform for expanding the public mobile data network.
But Baines explained that femtos are designed as private home base stations because they were originally intended to be coverage solutions, bringing voice access to homes and businesses the wide area network had trouble reaching. As network capacity emerges as the operator’s most pressing need, the femto is being redesigned as a capacity platform, Baines said. PicoChip’s latest round of femto silicon meets the local area base station (LABS) standard for use in a wide area deployments, supporting 64 simultaneous data connections and the background signaling traffic for 400 simultaneous smartphones. The femto isn’t restricted to the devices of a particular home or business, and it can be toughened up to meet the needs of an outdoor public network deployment. Such a femto may not carry the sub-$200 price tag most home femtos are going for today, but even at a premium cost the economies of scale for such off-the-shelf base stations are enormous, Baines said.
“They’re what microcells would have been if operators had actually deployed them and what picocells should have been when they were first designed,” Baines said. “The capex works out so that you can add lots and lots of small base stations for much less than the cost of adding a single macro cell.”
Next: Femto, Pico or Metro?
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