Someone on another list had a question about WiFi connection away from home,
and another person provided such a wonderfully detailed explanation of the way
WiFi and cell services work that I thought I’d share it with this list so that
others may benefit from the knowledge.
You really can't keep WiFi connection when you leave home. Hopefully I can help
you understand how it all works.
Your device has three radio sets built in. Actually it might have more
depending on what it is you have. Of interest are the WiFi radio, the Bluetooth
radio and the Cell radio. These are two way radios which means they can receive
signals much like an FM or AM radio and they can transmit signals back out to
other receivers like for example the cell tower.
The Bluetooth radio can talk to Bluetooth devices like headphones, speakers,
keyboards, other remote controller devices and has a distance of about 30 feet
or about 10 metres.
The Cell radio talks with the cellular towers scattered about. These towers
have more powerful transmitters and work mostly what is called line-of-sight.
Usually the outer limits are about 25 kilometres but usually a bit less.
Buildings, hills and other obstructions can interfere with the connection. Your
phone will make a connection with a tower and conduct signals with it and as
you move outside of the range of a tower that tower will talk to another tower
and negotiate a hand-off of your phone connection to one in the vicinity you
are entering if there is a tower available. If there is not you cannot use the
phone to talk or transmit data.Some companies share towers but not many so for
example my Rogers connection disappears just a little beyond the local Tim
Horton's just west of town whereas Bell customers have connection west at least
as far as Kapuskasing and quite possibly further. I don't know where Rogers
picks up again, going south it is well before Timmins.There is nothing south
down highway 144 except a little around the Watershed with any carrier.
The cell radio is used for regular telephone and data. There are Internet
connections to cell towers which convert Internet data to the data your phone
can understand and sends it over the air to your phone if you have data as part
of your phone plan.
The WiFi is a small radio in your home or other homes which receives Internet
data usually down a wire, either television like cable or telephone line wire.
This is connected to your WiFi router and can be passed along through an
Ethernet cable or a WiFi radio to your phone or laptop or what ever. That
transmitter is only good for a range of about 40 or 50 metres. All kinds of
things get in the way of that radio signal. I can hardly get my WiFi radio more
than a couple of metres beyond my front door but I can get it to the bottom of
my back yard. On my computer I can see signals from four or five of my
neighbours but the radio on my phone can't see or receive signals only from my
WiFi.There isn't much antenna in a cell phone.In an apartment building you may
be able to see several WiFi radios on your phone and this is why people set
them up with passwords, so you can't use someone's signal from the next
apartment or the one upstairs and they can't use yours. Clever people can
intercept your signals and watch for your credit card information for example
or read your e-mails if your WiFi radio isn't protected with a password and
sometimes even if it is.
Once you carry your phone beyond where it can receive your WiFi radio you no
longer can use WiFi. If you know the passwords you can connect to another WiFi
radio so, in theory if you know all the passwords of your neighbour's
apartments along the corridor and they have their WiFi routers on you could
theoretically connect to them in turn as you walk to the elevator.
Some cities have WiFi radios on utility poles in the street and if you are a
subscriber to that carrier, say Bell then you may be able to have portable WiFi
out in the street. I haven't actually looked when in Toronto but I understand
that there were plans to have the downtown covered with WiFi, I don't know
which carrier. When I visit in England, particular the south I see BT, British
Telephone have WiFi points associated with their phone boxes and other
locations.
So, when you get about 50 feet from your home router you can't receive or send
to your WiFi radio and WiFi is gone.
There are some places like coffee shops, sometimes bus and train stations which
offer free WiFi and others which offer it at a charge like some airport
service. Trains and busses now often also carry WiFi which they do through
their data systems much like how your Hot Spot works.
So now the Hot Spot. This uses your cell radio to send and receive data from a
cell tower as it would to say watch television on the phone and it links this
to your phone's WiFi radio. It makes your phone a little WiFi router. Using
your phone as a Hot Spot you can transmit Internet signals to a notebook
computer or other Internet device like an iPad that does not have Cell
capability. For example I have used my phone as a Hot Spot in England where I
had a data plan to allow my son's iPad have access to the internet through my
phone and my phone's cell connection. He did not have a data plan but wanted to
use his iPad to arrange rail tickets or something.
My phone used my data plan to connect to the cell tower and retransmitted that
through my WiFi radio which his iPad could talk to.
So, you cannot have WiFi on the move unless you are with a carrier which has
radios installed out on the streets which only happens in certain cities and
usually in particular parts of those cities or are on a bus which has a WiFi
radio built into it and retransmits signals it gets over the cell network.
If you want to listen to Spotify as you wander about you will need to stream
that using your data plan through the Cell towers.
Hope this helps you understand and might be helpful to others.
Dale Leavens
_______________________________________________
ATI (Adaptive Technology Inc.)
A special interest affiliate of the Missouri Council of the Blind
http://moblind.org/membership/affiliates/adaptive_technology
