Voice over GPRS?

[Robert Michel]

Salve Terrence,*!

Terrence Barr - Evangelist, Java Mobile & Embedded schrieb am Freitag, den 02. Februar 2007 um 17:52h:

> VoIP calls typically require approx. 120 kbit/s *each*
> direction, that's 240 kbit/s for a two-way conversation.

http://www.asteriskguru.com/tools/bandwidth_calculator.php
[*] speex   
[*] iax2

Incoming Bandwidth
Calls: 1 	
RTP: 4.69 Kbps 	
UDP: 3.13 Kbps 	
IP: 7.81 Kibps 	
Protocol: IAX2 REGULAR 
Audio Codec: 2 Kbps 
*IAX2 REGULAR is not using RTP or RTCP!

Outgoing Bandwidth
Calls: 1
RTP: 4.69 Kbps  
UDP: 3.13 Kbps  
IP: 7.81 Kibps  
Protocol: IAX2 REGULAR 
Audio Codec: 2 Kbps 
*IAX2 REGULAR is not using RTP or RTCP!

Incoming bandwidth: 	14.5 Kbps
0.01 Mbps
1.81 KBps
0 MBps 	

Outgoing bandwidth: 	14.5 Kibps
0.01 Mbps
1.81 KBps
0 MBps
Total bandwidth (incoming and outgoing): 29 Kbps
0.03 Mbps
3.63 KBps
0 MBps

29Kbps = 3.625 kByte/s


VoIP over cellular is just not feasible at this point.

I was not speaking about VoIP, I was talking about
asyncron voice services like the buzzthingy
"Push to talk" - but I do not whant to push - 
"Talk to talk" would be more smart - no need to 
press a button.

Without syncron communication the overhead would be
lower....

> >On 2/2/07, Robert Michel <openmoko at robertmichel.de> wrote:
> >>Salve!
> >>
> >>Does anybody has experiances/ideas about Voice over GPRS?
> >>How long is the delay? It could maybe used for asyncron
> >>voice communication Talk2Talk (instead of pushing a button)
> >>
> >>In Germany did three Prepaid Provider published new Tariffs
> >>with 0.24Euro/MB.
> >>German pages:
> >>http://teltarif.de/arch/2007/kw05/s24754.html
> >>data cost calculator:
> >>http://teltarif.de/mobilfunk/datenrechner.html
> >>
> >>I think with this tariffs using mobil data becomes
> >>interesting ;)
> >>
> >>By using 1KB/s for audio and some overhead, let
> >>us say 2 KB/s 0.24Euro/MB = 24 Cent for 500 seconds,
> >>60 seconds makes then about 3 cents. When both using
> >>this 6 cents. Hmm that would be interesting when
> >>the user makes often make brakes/pause in their talk.

Sorry guys, I was not asking about codecs, I was just asking
about delay on GPRS. ;)

Should I start again with a more simple example?
I will send a voicemessage of 20 seconds to my friend.
My Tarrif would cost with 60/1 second counting full 16 Cent.

20 second audio with 2.150 kbit/s  will create a file of
43 kbit = 5.375 kByte.
0.24Euro/MByte GPRS traffic with 10KB block will calculate
10 kByte for the message to my frind, this makes
0.0024 Euro = 0.24 Cent for me.

So my question would be how much delay will bring a GPRS
connection compared with normal internet connections?

Greetings,
rob









Greetings,
rob