If you think about, calling your mobile device a "cellular phone" is very strange.

Until the 1970s, the adjective "cellular" had nothing to do with electronics or human communication, the Oxford English Dictionary tells us. Cellular was mostly (and reasonably) applied to biological phenomenon, things to do with living cells. A 1716 writer could say, "Cutting is dangerous for the Tendons; and if that could be safely attempted, yet the Bones being cellular at the Joint, and porous, it would avail little," for example, or much later, an author in the 1968 New England Journal of Medicine could write, "Once cellular DNA is damaged, the 'message' is irretrievably lost in the medium."

There were other ways you could use the term. One could use cellular to describe some material that had a lot of cavities in it. So, Darwin could say, "I‥had noticed the presence of a few small pebbles of a very cellular basalt." Or you could describe a jail with the word, as a 1931 legal scholar did: "For prisoners on trial, the cellular system should be applied absolutely."

Looking at a portable communication device, it's not immediately apparent why it would come to be called a cellular phone. It's not made of biological cells, nor does it seem to be of, related to, or characterized by any other kind (prison, monastic) of cell.

The answer to this minor mystery is actually all around you. What's cellular about the cell phone is the network. Here's the diagram V.H. MacDonald used in his 1979 article for The Bell System Technical Journal, "The Cellular Concept."


What it depicts is the basic layout of a mobile phone network. It, as you can see, is composed of "cells" - which are defined by the transmission ranges of the towers at their centers vertices.*

The genius of the cellular network is that it allowed much more efficient use of scarce radio spectrum. Carriers can use the same set of frequencies over and over without creating all kinds of interference. In this diagram, A, B, C, D, E, F use different channels, but A1 and A2 as well as D1 and D2 use the same ones. Repeat the pattern over and over and you can use both lower-power towers and much less spectrum to service the same number of customers. As you walk (or drive) around the map, the mobile switching center hands you from one tower's infrastructure to the next one's. Or at least that's what happens when your call doesn't get dropped.

And, yes, this is an idealized diagram, of course. But looking at it, you can see why it might be natural to call these little electromagnetic chambers punctuated with a base tower nucleus a cell.

Going forward, the best way to increase the bandwidth available to mobile phone users is actually to shrink the cell. That requires, of course, a bunch of tiny cell transmitters, and those are actually coming onto the market, Christoper Mims reported in Technology Review.

* This is actually an interesting part of the system, as pointed out by Tim De Chant on Twitter. The towers are not located at the center a circle. The cells are usually hexagons and one tower with a tri-dimensional antenna sits at the vertex of three cells. More on this in subsequent posts.

We want to hear what you think about this article. Submit a letter to the editor or write to letters@theatlantic.com.