- The term cellular internet encompasses all smartphone,
and some tablet, internet connectivity made
via the connection to the carrier, to your provider
as opposed to a wifi connection.
And this all began with 2G:
the old school 2G speeds through your cellular network.
And there's a couple options with this.
GSM, the Global System for Mobile Communications,
is very common if you have AT&T or T-Mobile.
They would use GSM to make the voice calls,
and then the general packet radio service, or GPRS,
to send data through that cellular network.
If you have another provider,
like Sprint, or Verizon, or US Cellular,
you'd use CDMA to send the data,
and that's Code Division Multiple Access technology.
So two different options there,
but basically 2G is too slow.
If you wanna watch video or send photos,
2G's not gonna cut it.
So there are extensions to these services
which are used in most parts of the world now.
First of all, 2G evolved into 3G
with enhanced data rates for GSM evolution,
that's known as EDGE.
And then in many areas you can now get 4G and LTE,
as long as the mobile device complies
with the International Mobile Telecommunications
advanced requirements, the IMT advanced requirements.
And that means it has to have a 4G antenna
and it has to be in range of a 4G transmitter.
Most devices manufactured during this video,
during the time of the recording of this video,
are 4G with LTE. And so you can get speeds
of upwards of 50 to 100 megabits per second,
you know, depending on your connection.
Typically I'll get about 30 megabits per second,
and I'm pretty close to a radio tower
and that's a 4G LTE connection.
5g is also available in some areas
at 20 gigabits per second,
standardized as ITU IMT-2020.
Let's show a mobile device now
and show the actual connectivity
in the about section for the device
and show how it connects to the cell phone tower.
So here we have a Galaxy Note and you can see
at the top here that the wireless is on
and that's important, if the wifi is on,
that's gonna change what we see in our network settings,
but I'm in the settings right now,
and I'm gonna go to About Device,
and then from there, go to status,
and then you see the network we're on is T-Mobile,
and we see mobile network type is iWLAN,
well WLAN means wireless local area network.
That means that that's the wifi connection.
So in order to see
the actual network we're using for cellular,
I have to turn off the wifi.
So we'll go to the, swipe down
to the notification area,
turn off wifi, swipe back up
and then you see it has changed to LTE.
So I have an LTE connection for 4G
and it's at -107 DBM, which is a good connection
as I mentioned, real close to the cell tower.
So it gets a pretty powerful connection.
And if we swipe back down, turn the wifi back on,
because we definitely want wifi.
And we see that the mobile network type
changes back to iWLAN.
So, normally you'd go to the settings
and go to about and you might also
have to go to status within the about section
to see what network you're connecting to
and how good the signal is.
Okay. Let's talk about updates a little bit.
First PRL updates, that stands for Preferred Roaming List.
And it's used by cellular providers
that are working with CDMA technology.
So Sprint, Verizon, US cellular,
they're using CDMA instead of GSM,
they're gonna use these PRL updates.
And what that is is a database
that contains information about the providers' radio bands,
sub bands, service providers' IDs.
Ultimately it allows the phone
to connect to the correct tower.
Without this database of information,
you might not be able to connect correctly.
You might not be able to roam outside the network.
And so, when necessary,
the PRL updates are sent over the air.
However, you can also update this
by manually dialing a special number,
which is different for each provider.
Now, if your phone uses GSM, then that technology
and its radio functions are controlled by a chip
and software collectively referred to as baseband
and baseband updates are necessary to communicate
with the GSM cell towers.
So it's the same type of thing.
You know, basically, your PRL updates are used
by CDMA devices.
Your baseband updates are used by GSM devices.
Now next on the list we have, IMEI and IMSI.
These are both identification technologies.
IMEI stands for
International Mobile Station Equipment Identity
and it'll identify phones used
on GSM or UMTS or LTE networks.
It can often find this ID number printed inside the phone
on the battery or near the battery.
And it's only used to identify the device.
You can also find this
in the about section on the phone.
So once again, we're at our smartphone here,
we're in the settings.
If we go to about device
and then go to status
and scroll up a little bit,
we'll see the IMEI setting right there, there's our ID.
And so that identifies this individual phone
to the provider and also to any authorities if necessary.
And IMSI or IMSI
is the International Mobile Subscriber Identity.
So this is used to identify the user.
For GSM networks, this ID is loaded into a SIM card,
a Subscriber Identity Module card.
For CDMA networks, the ID is either loaded directly
into the phone storage
or to a Removable User Identity Module, RUIM,
which is similar to a SIM card.
So you wanna know about the IMEI
which identifies the phone or the device
and IMSI, which identifies the user.