Wi-Fi and Cellular
In 100 words or fewer, describe the difference between Wi-Fi and Cellular.
Our first inclination is to say they are really quite different. One ties a computer -- probably a laptop -- to the Internet, and the other ties a telephone to the telephone network.
But let's look at it a bit more closely. Both are wireless systems -- that is, radio. But Wi-Fi has a radio transmitter and receiver that operates only at a range of 200 feet or so. The range of cellular is measured in miles.
Wi-Fi's transmitter and receiver is called an access point. It is mounted in the corner of a room, or on a lamp post, or in a hotel lobby.
Cellular's transmitter and receiver is called a call site, or a base station.
Wi-Fi's access point is tied to a telephone central office with coax, fiber, or copper. Incidentally, the clever use of filters allows this access point to share the coax or fiber or copper with voice communications. The particular technology used is ADSL (Asymmetric Digital Subscriber Line). Cellular's cell site is tied to a telephone central office (or equivalent) with coax, fiber or copper. The telephone office, in both cases, can access the Internet.
So far, so good. Both use radio. Wi-Fi uses a near-by transmitter and receiver. Cellular uses a distant transmitter and receiver.
But don't they carry different things? Wi-Fi carries data from a lap top. Cellular carries voice from a cellphone.
Oops. Not any more. Voice is now digitized and carried by computers. Data has now been added to what we call smartphones. So both are perfectly capable of handling voice and data. And virtually every mobile device today comes equipped for Wi-Fi capability.
But what about capacity? In general, a Wi-Fi channel has a greater capacity than a cellular channel (maybe not for long: think 4G), but a Wi-Fi channel, or really the telephone line to which it is attached, has lots and lots of capacity. The cellular channel, on the other hand, runs out of gas when there are too many people trying to operate at the same time. A lack of spectrum, it is called. So the FCC is struggling to take unused spectrum from broadcasters and add it to the cellular supply.
But if a cellular channel is overloaded, why not spill the traffic over to the Wi-FI channel? Indeed, why not? You and I have Wi-Fi capability in our homes (Technically we should call this a local area network: LAN.). So does your neighbor. And if it is unprotected you could easy use it. And he could use yours. In fact, if you drove down the street checking for such channels, you would likely go quite a way before you drew a blank (Recently we visited Madeira, Portugal, and found we could check our email from the very large city park. For free.) To say it differently, there are certainly dozens or even hundreds of Wi-Fi transceivers in the footprint of one cellphone tower. And to say it yet one other way: Wi-Fi is the primary deliverer of data to smartphones.
All of this is not going unnoticed by the providers of cellphone service. Network operators are unfolding thousands of hotspots into organized mesh networks. AT&T itself offers access to more than 100,000 global hot spots, either by itself or through roaming arrangements. The intent, of course, is to lighten the load on the cellphone network.
AT&T is not alone. Whole cities are installing what amounts to Wi-Fi. And is there any reason why a small community -- that is, a homeowners association in some enclave, or an amusement park -- couldn't organize things so that there is a public Wi-Fi channel available to all customers?
So maybe this clamor for more spectrum is overblown. Maybe we should take what there is and use it.
What’s your take on this subject? Leave a comment and get the conversation going.