[Gllug] [OT] 3G speed / SIM issues on O2

Thu Nov 1 02:44:43 UTC 2007

I have been trying recently, to get to the bottom of my data rate issue
with the O2 UK mobile network.  I am with O2 Carphone Warehouse and have
been trying to achieve 3G speeds with them for a long while.

I went in to an O2 shop and got my phone browser downloading a large
file.  My measurements were done using the built in network monitor tool
on the Nokia E90 which shows in KB/sec***.  I first tested my CPW O2 in the
shop and got 17KB/s, then put in the demo O2 sim and got 50KB/s*, put
mine back in and showed the guy the difference.  In fact it was on the
strength of this, that I got an O2 Simplicity deal directly with O2 this
time.

When I got home and waited for the O2 sim to start working on its temp
number, I tested and got 17KB/s *sigh*.  So I went back to a different
O2 store and did the test again, this time with all three SIMs 17, 17
and 50 as you might expect.  I got the person to confirm and provide her
details to me so I could use her as a witness on later calls to the
helpdesk.

I have made about 10 calls over the past few weeks to CPW O2 and O2
directly, they all tell me that they have no idea what is wrong and that
their data support guys claim there is no special setting against my
account that would explain the speed.  Or indeed, that such a setting
exists for them to control it for anyone.

Despite explaining the situation, I'm often fobbed off with, contention
rates, signal quality, faulty phone and even, that's about what you'd
expect to get with 3G.

The situation of course, is that it's the same phone, same location,
same network (for contention issues, CPW O2 is still just O2), the only
thing changing is the SIM causing the speed difference.  Frankly if they
expect it's okay to be 10x slower than a rival they are barking, plus I
see that the O2 network can get 50KB/s from their own demo SIMs.

Extra things to point out :-

If I force my connection to GSM rather than forced UTMS (I also have a
dual mode which uses 3G in preference and switches down if it can't find
any), I get an EDGE symbol and my data rate is typically exactly the
same at 17KB/s.  EDGE should be able to get towards 35KB/s as I
understand it, if I'm very lucky.

It appears there is a frequency issue, where 3G is only possible on
2100, not 900 or 1800.  I'm not sure about that, but it's what these
imply:
http://www.3g.co.uk/PR/Sept2007/5182.htm
http://www.telegraph.co.uk/money/main.jhtml?xml=/money/2007/09/20/bcnofcom120.xml
http://www.cellular-news.com/story/26159.php
So it's possible certain SIMs lock to specific bands in preference, but
still show 3G symbols ?

When in Dublin, I got a UTMS connection, a 3G symbol and much faster
than GPRS connections on my really old SIM, before the newer 3G one.  I
didn't check the data rate though sadly.

The rates are typically very constant at these speeds, which definitely
looks like traffic shaping not random rates based on the signal strength
due to location, or current shared usage contention.

I have "3", Vodafone, T-mobile and Orange PAYG SIMs for tests, all of
these get exactly 50KB/s, Orange (or it might have been T-mobile, it was
a while back) told me when I asked about the speed, that I was limited
due to having a PAYG SIM rather than contract.  A test in a "3" store
got me 150KB/s!

O2 are the only network getting the iPhone.  It's a very cynical
suggestion, but it's possible they're trying to make it look less crap
when it launches for anyone switching phones, to find it's no slower.

I've been told that O2 have the ability to cap data throughput if you
exceed your monthly unlimited^Wfair usage quota, yet they deny any way
to shape traffic to the rate I'm seeing.

They obviously have ways to control your connection status based on your
SIM's ID, permitting MMS, Video calls, attaching the phone to different
networks (which would look like roaming if my SIM wasn't from the UK),
it would make sense they can also throttle speed, or technically more
likely, control which DHCP range I'm dropped in to, so that the routers
shape the traffic based on my IP.

So, my questions are:

Does anyone else on O2 see the same?

Does traffic shaping at 17KB/s (and 50 for that matter) seem likely to
be going on?

Does anyone have a contact at O2 who can push this further?

What is the deal with having to get special "3G" SIMs?  I can't see
anything indicating what changed in SIMs to stop my connecting at 3G
speeds.  http://en.wikipedia.org/wiki/Subscriber_Identity_Module

I'm 95% certain I was getting UTMS/3G in Dublin, and that was with a SIM
I've had for 9 years.  I also always got EDGE symbols for data when in
Europe but never got that in the UK**.  An old 2G only sim, which got
EDGE in France etc, couldn't get EDGE in the UK, but as soon as I get a
3G SIM it can do EDGE when in 2G mode, that HAS to be a network setting
not a hardware limitation.

So as far as I understand, the SIM just stores contacts, some special
codes for packet data connections (AT+cgdcont=1,"IP","APN") and has a
special ID, like a network card MAC, which the network providers
authenticate and permit to make calls and do stuff on their networks.  I
don't see why I keep being asked to physically change my SIM, does
anyone know ?

Sorry this is verbose, I wanted to make sure all the information was
available.  I also wanted to avoid the same repeated suggestions that
this relates to my location, my phone, or contention.

Thanks for any reply, even if it's that this is the wrong sort of list
for this query!

Damion

*This is acceptable, the 150KB/s on a "3" SIM is, well just stunning.  I
mean that's more than I get at home on my old ADSL line.  I get a nice
3.5G symbol indicating HSDPA on my handset in this instance.

**I also got HSCSD at 43kbps rather than 20odd in Britain.  In fact I
can't believe an old GSM data call was limited to 9,600 baud, when
Orange support 28,800.  In fact O2 did support 14,400 and then slowly
started to get turned down until only one near Euston still worked, I
had a call logged with them many years ago about this.  Just how evil
are they?

***I have tested under Linux (yeah a mention of Linux, almost making
it on topic), which a very basic firefox download rate indicator
window too.  Unfortunately my CPW O2 deal is 3quid a meg, so I really
avoid this!  I don't tend to have a laptop around when shopping.

-- 
Damion Yates - long time O2 sufferer.
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