Why is a mobile MIFI device necessary if the signal is received from a cell tower?

examples:

Comcast xfinity  (play now) for Ipad,  (TV) for Lqptops and desktops.
Any wifi will do.

More to follow

THANKS  

examples:

Itunes - keeps stalling out very poor if at all from cell

more to follow

examples:

These also won't work or are slow and stop and need to be restarted without WIFI:

New York Times Videos
Facebook Videos  slow and stop, work much better with wifi.
Generaly, multimedia video in most live feeds work much better with
WIFI.

I don't understand the technical advantage that WIFI through MIFI provides over
a connection to the cell not using WIFI.

However, there is one possiblity I have not explored.
 
Wifi from a hard wired bridge may be necessary.   Like a hotspot.  And a MIFI,
which is a transformation of a cell signal into an apparent WIFI, may in fact, not work, in the examples listed above.  I'm running these test using a Lynksys WIFI
bridge connected to Comcast High Speed Internet.

I shall visit an AT&T and a Verizon store, with my IPAD,  and ask for a demo.
The question will be, how will I know if I'm getting the WIFI signal from their
bridge and not their MIFI?  If my guess is correct,  Comcast error (you need
to be connected to WIFI)  may mean you need a hot spot link to a bridge
broadcasting high speed internet.
 
The Verizon MIFI is less than 10 bucks and I can always delete the software
and cancel the monthly payment.  There is no contract for these MIFI services,
according to Verizon coorporate sales support.
I'll be back.   We should save this posting, if I turn out to be correct.   It wil save
a lot of guys from being ripped off.  But there is always,  (I could be wrong).


Again,
Thanks for your help,
Howie

Thanks,
Howie

darr247,

Hi,

It's me again.   This is some more info related to our chat on 3/15/11.
May I ask, again, for your knowledge?

I have purchased an AS 2 Wi Fi Antenna EZ.com, 2.4-2.5 GHZ OMNI 8.5 DBI DA-24-03.
This was made for a marine system using an interface Base Unit EBU-101-01 module for a 12 volt supply, a Bullet2-HP Radio connected to the WI FI Antenna EZ external antenna, and a  EnGenius 11G Wireless Nano router.  It works well and connects to open WIFI and closed and protected  Xfinity, from my Ipad.

However,  there is a mystery to be solved.  "The game is afoot, Watson."

On my Ipad I have an application for Comcast's Xfinity.
I also have apps for PBS and for HBO streaming programming.

The PBS and HBO do not use WIFI.  They use the cell towers.
There is no noticeable difference between  the Xfinity WIFI and
the HBO/PBS Videos.  The quality and throughput seems to be
the same.   I have turned off the WIFI radio for the HBO/PBS tests.

The leading personal entertainment industry in developing leading edge
entertainment video and, now, interactive mechanical control
hardware,   use the cell towers.  And it works, obviously.
They had the first apps for the Ipad.  
NOT available from Itunes, of course.

I would have thought this was not possible, with all the fuss Xfinity makes
over WIFI?

Thanks for your time,
Howie