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I'm wondering if the device and/or any providers allow or support simultaneous voice and data connections. For exampleI would like to have a voice call open and be able to browse the web or run a custom app that connects over the network to my application server. Does the device and/or providers support this capability? Thanks.
Short answer is that they can't.
GPRS phones come in three classes. Class A which can do simultaneous voice and data. Class B is GSM and GPRS attached simultaneously but can only use one. Class C is either GSM or GPRS attached, but not both.
The radio rwesource allocation on Class A makes it impossible to implement using only one radio module. You have to use two RF front ends acting independantly. It is not economic to do this, also the power consumption would be too high.
The standards have introduced a "Simple Class A", or Dual Transfer Mode device that simplifies the radio resource allocation. You get a half rate Voice timeslot and a half rate GPRS timeslot in succession. This is easily (or more easily) implemented on a single radio module.
The downside is that you get crappy voice and slow data.
UMTS can support simultaneously voice and data as the radio resource allocation mechanism was designed to do this from the outset.
What UMTS devices are available
So, this begs the questions, what are the available UMTS devices and service providers. Thanks.
Being a newbie and only having an XDA1 I keep hearing the words GPRS and GSM banded about. Can someone plse tell me the differences between the two>???
Thanks john
GPRS is short for General Packet Radio Service, a standard for wireless communications which runs at speeds up to 115 kilobits per second,
GSM (Global System for Mobile Communications) 9.6 kilobits. so 11 times slower
GSM is mostly used for voice calls and SMS
GPRS for DATA-transfer ie MMS,surfing,email,...
GSM is usually charged by time ie minutes/second
GPRS by amount of data ie KiloBytes,Megabytes
You can surf or check email with GSM but then you'll have to use your GSM as a modem with a dial-in connection.
That's what i think, maybe I'm wrong but I'm sure the experts will correct me.
M4io said:
GPRS is short for General Packet Radio Service, a standard for wireless communications which runs at speeds up to 115 kilobits per second,
GSM (Global System for Mobile Communications) 9.6 kilobits. so 11 times slower
GSM is mostly used for voice calls and SMS
GPRS for DATA-transfer ie MMS,surfing,email,...
GSM is usually charged by time ie minutes/second
GPRS by amount of data ie KiloBytes,Megabytes
You can surf or check email with GSM but then you'll have to use your GSM as a modem with a dial-in connection.
That's what i think, maybe I'm wrong but I'm sure the experts will correct me.
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You are right.
GPRS is a data transfer protocol which runs OVER the GSM network. GPRS is a digital based protocol which is why high speeds can be achieved compared to GSM.
GPRS & GSM
Yep. generally speaking.........
Both can be used to surf the net (WWW) but generally GPRS is cheaper and faster.
GSM will dial up a server for your email and surfing. Your calls over GSM to a server generally cost 10 pence per minute, although it can be free depending on your personal tariff with your network (O2, Orange, Vodaphone, T Mobile, 3....)
GPRS is connected by your service provider, and you pay for what you download, by the KB, prices range fron £1 a megabyte to £7 depending on the supplier.
Coverage varies from mobile to mobile and area to area and of course network to network, for both GPRS & GSM.
Hi
For the networks, supporting GPRS meant a relatively simple firmware update to all but the oldest base stations. GPRS is pretty crude, if offers higher data rates at the expense of network capacity and makes poor use of the available spectrum (compared to W-CDMA G3 modulation schemes).
A basestation will have available to it a number of standard frequencies for GSM comms, say 50 channels, these channels will be different to the channels used on the neighboring base stations.
Each of these channels is split up into 8 time slots. In a GSM config, a mobile gets 1 timeslot, so 8 calls can take place 'at the same time' on the same channel. The base station and mobiles decide who is gonna transmit and when. This happens so fast that as far as the user is concerned they have a comms channel to themselves. This is TDMA Time Domain, Multiple Access.
Interestingly the time slots are so narrow that if you have phone A on located 20KM from the base station on timeslot 8, and phone B next to the base station on timeslot 2, then phone A will transmit its data before phone B, with the data arriving at the base station in correct time-slot order!
Mobile networks also support time-slot and channel hopping to get around network interference problems, and more importantly to counteract the issues of dopler shift when the mobile is moving at speed.
GPRS works simply by making more of these timeslots available to a single mobile. The fact that data is bursty means that the base station can hand out timeslots fairly efficiently. The 2 current systems for GPRS are class 8 and class 10
Class 8 offers 4 download timeslots and 1 upload timeslot
Class 10 offers 3 download timeslot and 2 upload timeslots
Each slot offers from 9.6K to 21.4K depending on network configuration (basically thats the width the RF channel, perhaps also the no of slots that the channel is split into - cant remember). In the UK I beleieve that each timeslot runs at 14.4K. You will however not see that since some of it is used for error correction.
O2 defaults to class 10. I dont know whether this is locked at the network level and I never tried changing it.
Class 10 will hence give max 43.2K down / 28800 up and
class 8 is 57.6K down, 14.4K up
You can knock 20% of those figures for error correction duties.
It would be possible for GPRS to run in 7/1 mode to give 7x14K4 = 100.8K down / 14.4K up. I dont think any networks or devices support such a configuration though!
Its been a while since I worked in this field so this info may be out of date by now. GPRS is not that much faster than HSCSD (high speed circuit switched data), but its much more efficient in its use of the bandwidth.
Ever been up a mountain miles from nowhere, had a screen full of signal bars but never managed to make a call?? Its a limitation of GSM (or rather the config of the network). A phone must be able to respond within the correct timeslot, if the phone is too far away then it can miss its slot altogether, hence full bars, but no calling! In the UK, the network setup means that the limit is around 25KM, in australia, they have extended this to around 100KM in rural locations.
Roll on EDGE - 2.5G++ its a new modulation scheme for GSM that makes *much much* better use of the spectrum. Should give us 256K on the move - i.e it will be pushing into 3G terratory bandwidth wise. Trouble is, GPRS was a firmware update for most base stations, EDGE is gonna require hardware. I would not be surprised though if we did not see networks giving up on taking 3G coverage beyond 70-80% of population, and rely on EDGE/GPRS to cover the dregs.
Nigel
Is there a way I can still get my GSM calls when I am connected to GPRS ?
As a matter of fact I do when the GPRS is Idle. But when there is some data transfer happening and a call comes in, It goes off to my voice mail !!!
Isn't it supposed to put the GPRS on hold and take the call ?
Any settings or any ideas ?
regards,
Arun
Hello everybody!
I know this looks like it belongs in the networking forum, but I'd like an answer specific to the Jamin.
The problem is this:
If I am downloading a page with IE it blocks incoming calls. If the GPRS connection is active but no data is transferring calls go through.
I found an old thread on this and it seems to be a phone specific problem (some models do this and others don't).
So am I missing something?
Is this a ROM / hardware thing, or is there a setting some ware, or maybe this is dependent on the cellular provider?
Does anyone else here experience this? Please let me know and if my question is stupid don't hesitate to point it out.
P.S. I am using latest official i-mate ROM 2.13.9.23 WWE and 1_02.20.21 radio.
Sounds quite strange, if I remember well and from experience in low-coverage areas the GPRS signal is dropped first if calls are made on the handset and there is not enough bandwith for both. But I am sure we find a GSM network expert here that can enlighten us. Interesting question.
Hi,
I have aone xda Atom.
Have the same problem.
For example media player streaming internet radio , phone calls don´t came through. Or 1 in 10 came through.
If I´m connect without streaming or downloading then the call came through
Regards
Josef
As far as i remember you can't recieve any calls exactly when downloading. When GPRS is simply on it's ok. Don't really remember why...
As far as i remember you can't recieve any calls exactly when downloading. When GPRS is simply on it's ok. Don't really remember why...
The phone and GPRS are mutually exclusive.
We have a GPRS application that needs the connection to be alive as much as possible to receive incoming data. Phone calls get in the way of this, which is why I know the problem exists.
I do not have a validated reason for the problem (I believe they use the same transmission streams over the network, which means the network needs to know whether it is transmitting data or voice. Data needs to be reliable, with no dropped packets, while voice needs to be quick, with dropped packets being ignored, or something similar anyway).
Graham.
Hi,
Will like to add. Have one Universal too.
With the Universal if I ´m downloading or listen internet radio, when a call cames the downloading is suspend. Allways.
Regards
JoseF
Seems like it depends on service provider not on the device... I remembere the time when GPRS have just been started on NW Megafone - GPRS traffic lived like poor homie with the voice transmissions so when many peoples speaks - gprs is dead. Nowdays we got edge and gprs works fine. But still we got subj
Well, at least now I know it's not a matter of settings or ROM version.
Still not sure if it's the phone or the provider, but since I don't fell like switching either of them (specially the phone ) I guess I'll have to live with it.
Just to clarify: I don't expect simultaneous voice and data, but it would have been nice if incoming calls killed GPRS to get through even if I am in the middle of a download.
P.S.
Thanks every one for your prompt responses!
Not much help, but this is among the reasons I use a multicard - maybe you want to consider it. A multicard is two SIM cards with the same number, but one card is activated for GPRS/UMTS and SMS, and the other one for voice traffic and SMS. Especially with a flat data rate, GPRS is always on, and one does not have to use the Prophet as a phone all day. It means you have to carry two phones, but for a heavy user working with these tools all day it makes perfect sense. Just my five cents...
Just to clarify: I don't expect simultaneous voice and data, but it would have been nice if incoming calls killed GPRS to get through even if I am in the middle of a download.
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Click to collapse
Hm... Let me think... I remember there was such a nice setting on my Panasonic GD87, called "Wait for incoming call" or smt like this. Nice feature. Gives the ability of cellular phone disconnect from gprs and recive incoming call. Seems like I'll be missing it
Are there any news on this?
I have the same problem, that incoming calls are blocked when using GPRS.
Hi yoda_143.
I recently got to do some testing at work with phones from different manufacturers (MIO, HP, ASUS) and my SIM.
The conclusion: It is not the Jamin!
On all phones incoming call was blocked while data was transferred.
I haven't had the chance to test it with different providers, but I suspect this will not make a difference.
It would be nice though if there was a way to give voice calls priority even if it meant starting the download over from the beginning after the call ends.
Guys this might help
http://www.gsmworld.com/technology/gprs/class.shtml
Class A, Class B & Class C?
The class indicates the mobile phone capabilities.
Class A
Class A mobile phones can be connected to both GPRS and GSM services simultaneously.
Class B
Class B mobile phones can be attached to both GPRS and GSM services, using one service at a time. Class B enables making or receiving a voice call, or sending/receiving an SMS during a GPRS connection. During voice calls or SMS, GPRS services are suspended and then resumed automatically after the call or SMS session has ended.
Class C
Class C mobile phones are attached to either GPRS or GSM voice service. You need to switch manually between services.
BUT; even my Wizard claims that it's Class B, does the same thing and blocks incoming calls while downloading. So what does it mean?? Maybe a network provider issue :?:
From my use of XDA2i it appeared that phone can transfer GPRS data or phone call not both at the same time.
If you want both then you will need 3G/UMST
The Universal will happily allow phone calls whilst surfing over a 3G connection. Even on Universal you lose the ability for data&phone if you are using GPRS.
I see but it says everywhere that Class B phones has to stop data transfer and accept incoming calls. My old Sonyericsson T630 was doing the job! BTW my network provider claims in their website FAQ like this..
Q- During download with GPRS, if an incoming call occurs, do my GPRS connection stops?
A- During download with GPRS, if an incoming call occurs, you can easily accept the call. During call, your data transfer suspends and after call ends, goes on where it was suspended.
EDIT: I talked with network operator today and they changed their web site saying after a few tests that "u can't suspend and resume GPRS data flow, while data flow incoming calls are blocked!!"
While Wizard is Class B and the operator uses NOMII , all architectural must be wrong.
Really WEIRD, isn't it?
This article is also interesting (don't look "symbian" thing, it is a general article about GPRS/NOM)
http://www.symbian.com/symbianos/standards/symbianongprs.html
Network operation mode and phone classes
The Network Operation Mode, or NOM, is responsible for the capabilities of a GPRS network, while the class indicates the mobile phone capabilities. On NOM 1 networks, mobile phones with the right capabilities can have simultaneous circuit- and packet-switched connections. On NOM 2 networks, mobile phones can remain attached to the GPRS networks when in a voice call but they can't transmit data at the same time. On NOM 3 networks, mobile phones can either establish a packet-switched data connection or a circuit-switched voice one but they need to disconnect from one to establish another.
Class A phones can make full use of NOM 1 networks: they can use circuit-switched voice and GPRS data services at the same time. Class B phones can register circuit-switched voice and packet-switched data services at the same time but may only use one at a time. Should the user receive a call while on the internet, they can take the call and GPRS service will be suspended, resuming once the voice call is ended. Resuming GPRS service is much faster than re-establishing a data call. Class C phones can only register for packet-switched data or for circuit-switched voice services; if the user chooses GPRS, then they will be totally unavailable for GSM calls and reciprocally.
End-users will initially have access to Class B mobile phones, which are able to make and receive calls while simultaneously being registered with GPRS services - GPRS services will automatically be suspended and resumed at the end of the call. Class B phones only support one active service at a time - GSM (voice, fax or data) or GPRS (data) - though both services can be registered with the network and the phone can switch automatically back and forth. However, should the user roam to a network area that is NOM III, their Class B phone will effectively be working as a Class C phone.
New applications designed to run in an online environment will be developed to take advantage of GPRS and 3G networks. The user may well experience a 'blurring' of applications whereby they won't need to switch task nearly at all.
my universal (t-mobile) on 3g in australia is quite fine i tested the situation you guys are talking about and itl mmove he program to background and take the call (both do run simultaniously (internet might slow down alittle by about 3 Kb/s so hope this helps someone... byebye (GREAAT WEBSITE!)
I just switch to 3G instead of 2G. I want to experience the high speed internet suffing via my handset.
But I found the problem is that the phone call can't came in if I using the 3G data. Not even transfer to security services. Just a "Busy tone".
Check with the service provider and they are now checking with their technical dept to see if they can found the problem.
They said that the call should be able to come in because the phone call channel is different to the data channel. :roll: :?:
Anyone experience the same problem?
I experienced the same problem with my CHT9000. You may change the setting to GSM then call can come in when you using GPRS but you can't enjoy the high 3G speed on data transmittion. Anyone has better solution?
complicated issue; can be the same with GPRS/EDGE ; I made a lot of research read below;
http://forum.xda-developers.com/viewtopic.php?t=54738&highlight=
It is interesting. I don't have this kind of problem while I am using GPRS. But it happen to my new network provider (3G).
Lucky you then :lol:
At least you have GPRS/EDGE working and as a result it is absolutely a network provider issue.
I talked every detail with a guy in my Net. Op. and seems can be solved by "tricky switching something on" but they could not make me believe that this is not thier mistake. Because Class B phones MUST suspend the data flow and accept incoming calls for the technical point, only class A phones (no retail ATM) can make data flow and GSM talk at the same same.
GPRS is 2G, EDGE is 2,5G and same tecnique as 3G, only speeds are lower, so I beleive if u use 2G suspend while incoming calls your Net.Op. can solve the problem if they want :wink:
I have this strange problem with my vario II.
I am using Tmobile GPRS on both 2g and 3g network, If I am using the 2g phone works if If am using 3g phone doesn't work if I call it, the phone rings but doesn't alert me. The most annoying problem I am having is the phone switches between 2G and 3G if I am in a call the phone goes silent can't hear anything the display shows the call as connected and around 5-10 seconds later the phone drops call drops. This happens even if the data connection if not active.
What is the deal with that? anyone else have this problem.
Phone band settings are below
network type
Auto
GSM
GSM(900+1800)+UTMS(2100)
I've just discovered the same problem with my orange branded tytn, I'll be phoning them later to ask what they can do about it.
xxnoelziexx said:
I am using Tmobile GPRS on both 2g and 3g network, If I am using the 2g phone works if If am using 3g phone doesn't work if I call it, the phone rings but doesn't alert me.
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Click to collapse
Works perfectly on T-Mobile UMTS for me. I did flash the Dopod 838Pro ROM though.
will flash the dopod rom in the morning. I am currently using the imate rom, and the tmobile rom the device shipped with had to many slow downs so it had to go. if this fixes the drop out issue I will be happy if not the phone will be in its box till a rom update. got the phone cheap so don't really mind. nice phone/pda apart from this issue in my line of work can't afford to miss or drop calls.
so is this a hardware or a software issue then?
No harware problem, it is absolutely software issue. Read my posts above and the links I gave
No problems here I'm afraid.
Voda v1605 running the Voda Blackberry Client, so either 3G or GPRS (where no 3G available) on all the time. Calls and SMS received perfectly.
Only issue I have is when using 3G, unlike home wired broadband, I cannot use multiple applications through the single 3G connection (e.g. Blackberry client on and surf too)
Steven
Hi, anyone tried connecting to 3G in a non 3G coverage area and the connection automatically switch itself to GPRS instead of EDGE, even if EDGE is available in that area? I wanted to connect my device to EDGE if 3G is not available and not to GPRS. Pls advice... Cheers!
Hey,
The way mobile networks and handsets work is the phone will always choose the highest available connection speed possible and the network based on capacity and available resource will assign the mobile what it can. That's why a phone will always look for a 3G network before a GSM one. When the phone initiates a packet connection to the network it includes a message which tells the network it's capability such as EDGE supported, what class of GPRS capability (4 slots down / 2 up etc...) and then the network based on this message assigns the phone a resource. Most networks nowadays have enough resource to give you a fairly good connection. For example if you support EDGE you will be given EDGE assignment (8QPSK instead of 4GMSK) as the ways the data is scheduled in the network is no different between GPRS and EDGE only the connection between the handset and network is faster.
What actually happens when you change from 3G to GPRS/EDGE is you drop the connection in 3G (move out of coverage) and based on the neighbouring channel list you received off the 3G cell you look for the most suitable GSM cell. Now this cell may or may not support EDGE but in either case the handset will PRACH on the cell, the cell with then ask the handset to authenticate and in this message you send your handset capability and also information about the last RNC/PCU (in this case the one connected to the 3G cell) you were on. The new PCU then signals with your old one and re-routes the data in the backbone of the network to you on your new cell. There will be data loss but the higher layers (application) should ask for re-tries for the missing data if it's TCP data.
In summary your connection priority (if the network supports all these technologies) is: HSDPA > UMTS (3G) > EDGE > GPRS > HSCSD > CSD
Hopefully this answers you question and adds a bit of extra info...
EDIT:
P.S. Not many networks support EDGE at present but most have plans to support it in the next 12-24 months.
Gav
How do you know you are on GPRS and not EDGE??
Hi Eeter,
I don't think there is any indication on the device You could tell my doing a speed test. If you are on a GSM network where you know EDGE is used then more than likely you will be using it instead of GPRS.
Gav.
There is an easy way:
1. Install the fieldtest utility
2. Go into a data session ( streaming radio ....BBC or others )
3. Check the Fiedtest EGPRS page and look for the downling coding
4. If it shows a CS1 or CS2 it is GPRS. If it shows MCS5 etc.. It is EDGE
Checking speed only is misleading. EDGE can be slow sometimes and the speed depends not only on the air interface but on the core internet side too
Hi eeter,
Yeah I agree that a speed test could be miss-leading.
Checking if you are using a MCS instead of CS will say for sure you have an EGPRS connection.
Gav.