What Are Small Cells?

By far the most confusing industry term that is widely used today is ‘small cell’. I see at least a couple of different articles every day talking about some aspect of small cell deployment. What becomes quickly clear after reading a few such articles is that the small cell terminology is being used to describe a number of different technologies.

A lot of the blame for this confusion comes from the CTIA, the industry group that representing the large cellular carriers. As part of lobbying the FCC last year to get the ruling that allows the carriers to deploy devices in the public rights-of-way the CTIA constantly characterized small cell devices to be about the size of pizza boxes. In reality, there are devices that range from the size of a pizza box up to devices the size of dorm refrigerators.

There are a number of different kinds of deployments all being referred to as small cells. The term small cell brings to mind the idea of devices hung on poles that perform the same functions as the big cellular towers. Fully functional pole-mounted cellular sites are not small devices. The FCC set a limit for a pole-mounted small cell to be no larger than 28 cubic feet, and a cell tower replacement device will use most of that allotted space. Additionally, a full cell tower replacement device generally requires a sizable box of electronics and power supply that sits on the ground – often in cabinets the size of the traditional corner mailbox.

These cell-tower replacements are the devices that nobody wants in front of their house. They are large and can be an eyesore. The cabinets on the ground can block the sidewalk – although lately the carriers have been getting smarter and are putting the electronics in an underground vault. These are the big ‘small cell’ devices that are causing safety concerns for line technicians from other utilities that have to worry about working around the devices to fix storm damage.

Then there are the devices that actually are the size of pizza boxes. While they are being called small cells just like to giant boxes, I would better classify these smaller devices as cellular repeaters. These smaller devices re-originate cellular signals to boost coverage in cellular dead spots. I happen to live in a hilly city and I would love to see more of these devices. Cellular coverage here varies widely block by block according to line-of-sight to the big cellular towers. Cellular carriers can boost coverage in a neighborhood by placing one of these devices within sight of a large tower and then beaming from there to cover the dead spots.

If you look at the industry vendor web sites they claim shipment of millions of small cell sites last year. It turns out that 95% of these ‘small cell’ devices are indoor cellular boosters. Landlords deploy these in office buildings, apartment buildings and other places where cellular coverage is poor. Perhaps the best terminology to describe these devices is a cellular offload device that relieves traffic on cell sites. The indoor units use cellular frequencies to communicate with cellphones but then dump cellular data and voice traffic onto the broadband connection of the landlord. It turns out in urban downtowns that 90% plus of cellular usage is done indoors, and these devices help to meet urban demand cellular without the hassle of trying to communicate through the walls of larger buildings.

The next use of the term small cell is for the devices that Verizon recently used to test wireless broadband in a few test markets. These devices have nothing to do with cellular traffic and would best be described as wireless broadband loops. Verizon is using millimeter wave spectrum to beam broadband connections for a thousand feet or so from the pole-mounted devices.

The general public doesn’t understand the wide array of different wireless devices that are being deployed. The truly cellular devices, for now, are all 4G devices that are being used by the cellular carriers to meet the rapidly-growing demand for cellular data. The industry term for this is densification and the carriers are deploying full cell-tower substitute devices or neighborhood repeaters to try to relieve the pressure on the big cellular towers. These purely-cellular devices will eventually handle 5G when it is rolled out over the next decade.

The real confusion I see is that most people now equate ‘small cell’ with fast data. I’ve talked to several cities recently who thought that requests for small cell attachments mean they are going to get gigabit broadband. Instead, almost every request for a small cell site today is for the purpose of beefing up the 4G networks. These extra devices aren’t going to increase 4G data speeds, aren’t bringing 5G and are definitely not intended to beam broadband into people’s homes. These small cells are being deployed to divvy up the cellular traffic to relieve overloaded cellular networks.