We’re accustomed to seeing the cellular networks looming above us – big antennas mounted on towers, masts and the rooftops, beaming down their signals from up on high. But the mobile network soon will start taking on a more human scale.
The mobile industry is miniaturizing the basic building block of mobile networks: the cell. These so-called small cells work the same way as big macrocells. They offer the same speeds, carry the same capacity and host the same phone calls as their tower-mounted counterparts. The difference is they cover a lot less ground.
That’s important because the mobile network is ultimately a shared network. Just because that LTE tower in the distance can support 100 Mbps, it doesn’t mean you’re ever going to see anything close to that speed on your smartphone or tablet. That capacity is sliced and diced up among all of the devices connecting to the tower at any given moment. However, once you start shrinking down the radius of each cell, then far fewer devices are linking to it. There are fewer resources to share, and everyone enjoys faster speeds. Any single small cell isn’t going to add much capacity to the network, but when you start deploying them in dense clusters, those capacity gains are substantial.
As an example, let’s say a macrocell with a one square-mile radius offers up to 100 Mbps in LTE capacity. A cluster of 20 small cells covering roughly the same area would support – theoretically at least – 20 times this capacity.
Consequently, mobile operators are eyeing small cells as a means of layering immense quantities of 4G capacity in areas where data demand is highest: urban corridors, high-traffic indoor areas and commercial districts. For example, Verizon has begun a small cell rollout in the main tech company corridors of downtown San Francisco, mounting them on utility poles on a block-by-block basis.
The macro network isn’t going away. Those big towers provide the coverage necessary to make our devices truly mobile. But in dense cities, those macrocells eventually will act more like big umbrellas. They’ll ensure we can get signals in our cars and in our less dense residential neighborhoods. They’ll provide network glue as we move between clusters of small cells. That coverage continuity will be crucial, but small cells will do most of the heavy lifting when it comes to data traffic.
There are still some technical obstacles the industry must overcome before we get that multi-layered network. When you start sticking small cells under that macro-network umbrella you inevitably get interference. One of the biggest problems the mobile industry has to sort out with small cells is ensuring that they play nice with their larger counterparts. But new standards developed for 3G and 4G networks are promising to keep that interference in check.
The small cell transformation won’t happen overnight, but many global operators are already deploying these tiny base stations in the urban fabric of our cities. Vodafone is sticking small cells on billboards and street furniture in Amsterdam. AT&T is installing them in malls, stadiums and pedestrian areas in major U.S. cities (it’s even putting them in Disney World).
So if you happen to see some strange box pop up on a neighborhood utility pole, you may want to check your phone. You might find you’re getting a much stronger signal.
Editor’s note: This is a guest post by Kevin Fitchard who is a journalist covering the mobile industry and wireless technology. He most recently wrote for Gigaom.