maemo.org - Talk - GPRS / EDGE / 2G data connections dropping during, or blocking, voice calls

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maemo.org - Talk (https://talk.maemo.org/index.php)

- Maemo 5 / Fremantle (https://talk.maemo.org/forumdisplay.php?f=40)

- - GPRS / EDGE / 2G data connections dropping during, or blocking, voice calls (https://talk.maemo.org/showthread.php?t=36774)

Pigro

2010-03-03 23:40

Re: N900 can't receive calls while using GPRS data

4 Attachment(s)

Screenshot #1 @ 22:35

2G signal
no call in progress
talk.maemo.org showing most recent post @ 10:33

Screenshot #2 @ 22:37

call in progress (initiated by n900)
talk.maemo.org showing most recent post @ 10:33

Screenshot #3 @ 22:40

call still in progress
talk.maemo.org page refreshed, showing most recent post @ 10:34

Screenshot #4 @ 22:40

call still in progress
talk.maemo.org page still showing most recent post @ 10:34

You'll need to take my word for it that the screenshots haven't been messed with, and that the same call remained in progress throughout the test ... but this hopefully shows that it's technically possible for a GPRS data session to coexist with a voice call on 2G.

Admittedly, refreshing the browser was quite flaky during my test (I had to stop/reload several times) but TBH that happens to me on a 2G connection in this location quite often even without a voice call in progress.

shadowjk

2010-03-03 23:48

Re: N900 can't receive calls while using GPRS data

Actually n900 supports simultaneous voice and data on edge too, but the number of operators worldwide that support it cn probably be counted with one hand.

Pigro

2010-03-04 12:42

Re: N900 can't receive calls while using GPRS data

from n900 technical specification (http://maemo.nokia.com/n900/specifications/):

Quote:

Data network:
GPRS class A, multislot class 32, maximum speed 107/64.2 kbps (DL/UL)
EDGE class A, multislot class 32, maximum speed 296/177.6 kbps

From the (dreaded) Wikipedia (http://en.wikipedia.org/wiki/General...adio_Service):

Quote:

Hardware

Devices supporting GPRS are divided into three classes:

Class A
Can be connected to GPRS service and GSM service (voice, SMS), using both at the same time. Such devices are known to be available today.
Class B
Can be connected to GPRS service and GSM service (voice, SMS), but using only one or the other at a given time. During GSM service (voice call or SMS), GPRS service is suspended, and then resumed automatically after the GSM service (voice call or SMS) has concluded. Most GPRS mobile devices are Class B.
Class C
Are connected to either GPRS service or GSM service (voice, SMS). Must be switched manually between one or the other service.

From Vodafone forums (http://forum.vodafone.co.uk/index.php?showtopic=48443):

Quote:

With DTM, (also known as simple or pseudo class A) both voice and data are on the same frequency and coordination is done by the network. The original idea of Class A was to operate in the CS domain (voice) and PS domain (data) with complete independence which did mean supporting 2 frequencies at the same time (not just 900 & 1800 but also 2 frequencies within the same band). This would have made handsets hugely complex so it never really happened and so when you see Class A in the specs it means DTM.

It works on GPRS and EDGE but since 1 timeslot is taken up by voice the data transfer will be a bit slower when doing DTM.

I briefly mentioned this new capability in another post here earlier but DTM is still a very rare sight on 2G GSM/GPRS networks throughout the world and Voda has only been doing it since the new year although the specs and capable handsets have been around for a bit. A related benefit is even if you have a handset that isn't capable of DTM it still benefits in that you will not miss incoming calls or get delayed texts when transferring data which was a problem on 2G up until now.

daemonfin

2010-03-04 13:01

Re: N900 can't receive calls while using GPRS data

Quote:

Originally Posted by hermitoz (Post 523494)

So this is why people suddenly stopped calling me:P Haha, I had realized that if i had an active data session I was unable to recieve calls, however SMS seemed to work.
I mostly use GPRS to conserve battery, it's really unneccessary with 3G for IM's and small quantities of surfing. But if I always use 3G people will be able to call me?
I will need to experiment on this, and see if the battery time will be acceptable.

I dont have that problem.

Spotfist

2010-03-04 14:01

Re: N900 can't receive calls while using GPRS data

the reason why this bug is "not replicable" is becasue people seem to be doing it wrong, loading a webpage will not always allow for a full traffic load, you really need to hammer the 2g connection for this issue to take place. I can goto the Ovi store and call myself however if I try and stream some media over 2g I cant get the call through no matter how many times I try.

Using Skype, jabber etc will not rape the 2g connection, I is a "check every now and then" kind of traffic allowing for a call to come through, this is a rather annoying bug and it seems some poeple are getting that sweet spot gap in the data tranmission where the call can come through.

It's annoying becasue I have poor 2g signal and am getting it in the ear from the misses cuz "I have my phone turned off" when actually im busy streaming music :(

Am on Tmobile by the way ;)

sjgadsby

2010-03-04 14:14

Re: GPRS / EDGE data connections dropping during, or blocking, voice calls

The following threads have been merged into this thread:

"calls not received" with twenty-eight posts
"N900 can't receive calls while using GPRS data" with forty-four posts

bitflung

2010-03-04 16:57

Re: N900 can't receive calls while using GPRS data

Quote:

Originally Posted by Pigro (Post 555390)

from n900 technical specification (http://maemo.nokia.com/n900/specifications/):

From the (dreaded) Wikipedia (http://en.wikipedia.org/wiki/General...adio_Service):

From Vodafone forums (http://forum.vodafone.co.uk/index.php?showtopic=48443):

Interesting - I see I was completely wrong in thinking that it was not feasible to have simultaneous voice+data on 2/2.5G; thanks for clarifying and putting up with my misinformation gracefully.

With that point cleared up, we still have plenty of networks which function properly on other devices but fail to connect incoming calls while 2/2.5G packet data is active on the N900.

I would be interested in knowing which networks work, and which ones don't. So far, I have heard reports (including my own) that the N900 suffers from the described issue on the following networks:

- AT&T (USA)
- T-Mobile (UK)
- O2 (UK)

Can anyone add to this list, or state that they use one of these networks and do NOT experience the flaw?

Pigro

2010-03-04 17:41

Re: N900 can't receive calls while using GPRS data

Quote:

Originally Posted by bitflung (Post 555758)

Interesting - I see I was completely wrong in thinking that it was not feasible to have simultaneous voice+data on 2/2.5G; thanks for clarifying and putting up with my misinformation gracefully.

No problem :-)

It will be interesting to see others experiences & get a better picture - judging by the Vodafone eForum guy's post it sounds like (pseudo)simultaneous access is still quite rare.

I'm certainly pleased that Voda are not ditching my incoming calls when I'm on a 2G GPRS data connection, and any actual data bandwidth still available to me once I take that incoming call is a bonus. Also agreed that it is totally unacceptable for incoming calls to be lost in such circumstances, good luck tracking down root cause to the device and/or the operator ...

egoshin

2010-03-04 19:33

Re: N900 can't receive calls while using GPRS data

Quote:

Originally Posted by Pigro (Post 555390)

The problem is - it is a provider choice of accepting your device as class A or B or even C. If provider has N900 marked as class A phone - sure.

BTW, it looks like before PR1.1 update the cellphone firmware doesn't indicate N900 as a smartphone to provider.... and may be - as class A too.

Spotfist

2010-03-05 09:37

Re: GPRS / EDGE data connections dropping during, or blocking, voice calls

I would just like to point out that this issue does and does not occur on tmobile dependant on how much bandwidth you consume over 2g, as stated in my previouse post I am on tmobile uk, I can goto a webpage while it is loading and phone myself however if I had to go to youtube or stream music I cant get through, it seems that some people may be reporting that they are getting through on there network when acutally if they nailed there 2g connection they may find they cannot get through.

My experience is that a webpage may allow for gaps in the bandwidth were the call can squeeze in whereas when buffering music there is no gap...

Pigro

2010-03-05 12:47

Re: GPRS / EDGE data connections dropping during, or blocking, voice calls

ok, for clarity, Voda UK, is still letting calls through while I'm streaming a vid from youtube. I don't reccomend watching "smells like teen spirit" over 2G though, unless you really like the look of the "buffering" animation :-)

daemonfin

2010-03-05 13:04

Re: GPRS / EDGE data connections dropping during, or blocking, voice calls

I have same problem only in 2g

Hossie

2010-03-05 13:39