Verizon is laying down 400 tiny cells in SF to boost LTE capacity

In the coming months, workers and visitors along San Francisco’s major tech corridors may notice some very big improvement in Verizon’s 4G network speeds in some very specific places. The carrier plans to blanket the city’s SOMA, Financial District, Market Street and North Beach neighborhoods with 400 pint-sized transmitters called small cells.

You can think of small cells as a big tower-mounted macro cell shrunken down to size of your dorm-room space heater. They’re mounted on utility and light poles, and while they carry the exact same amount of capacity as a big macro cell, that capacity is concentrated in a much smaller area — in [company]Verizon[/company]’s case, a 250 to 500-foot radius.

Small cells are intended to be surgical tools in the network: Carriers use them to layer significant amounts of capacity in high-traffic and high-demand places. And in the case of San Francisco, there’s probably no more high-demand area than downtown, where the city’s tech industry is concentrated and everyone always seems to be surfing on smartphone or tablet, said Eric Reed, VP of entertainment and tech policy at Verizon.

A rendering of what two small cells (on different frequencies) would look like on an SF light pole.

A rendering of what two small cells (on different frequencies) would look like on an SF light pole.

Verizon is using small cells in other cities — New York, Chicago and Phoenix to name a few — but the San Francisco network in particular is an apt proving-ground for the technology because Verizon’s customers scarf down mobile data there like few other places in the country, Reed said. Specifically, Verizon anticipates a three-fold boost in capacity in the areas covered by these [company]Ericsson[/company]-designed transmitters, and customers should also notice some big increases in average speed as tinier cells split their capacity among fewer users.

There have been other small cell deployments in the U.S. — [company]AT&T[/company] is in the middle of a big one — but Verizon’s is particularly notable because of its extent. It’s packing a lot of cells into a limited area to create a very dense network, rather than just plopping cells down here or there to fill a coverage or capacity hole. While these cells won’t be in a massive single cluster, they’ll be spaced near enough that Verizon has to be careful they aren’t too close, otherwise their signals might interfere with one another, Verizon’s director of network engineering and operations Jake Hamilton told me.

What Verizon is building is what is known as a heterogeneous network, or HetNet, a kind of multi-layered system, which reuses the same spectrum over multiple radio technologies. Both the small and large cells will transmit over the same frequencies, which normally would result in a murky soup of cross-interference, but Verizon and Ericsson are taking a lot of steps to make sure that doesn’t happen. According to Hamilton, they’re shaping the radio patterns from Verizon’s towers so they wrap around the small cells where possible, and they’re also using an LTE-Advanced technique called enhanced Inter-Cell Interference Coordination (eICIC) to make the two networks behave as one.

Verizon is working with the city of San Francisco to use its utility infrastructure, and it’s currently getting all of its paperwork in order so its installation crews can get to work in the second quarter, Hamilton said. Verizon expects to have all 400 cells up and running by the end of the year.