Database Users

Can someone plse explain difference between GPRS & GSM

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.
Click to expand...
Click to collapse
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

Can you prevent switching to UTMS?

Hi,
I've found that the switch between GPRS and UTMS can be a bit of a PITA. It causes TomTom to drop it's traffic connection, and makes web browsing in a marginal 3G area practically unusable as it's chops and changes between GPRS and UTMS (3G).
I've tried to create a new "Cellular Line" connection with the *99# dialup settings, in a hope that this would connect me to GPRS without switching to UTMS if available, but I can't get it to work - it just says "No modem at above number".
Has anybody got a solution to this?
Cheers,
Steve.

If you select Settings -> Phone -> Band and choose GSM (instead of Auto), what happens? Does it stick to GSM? I think it should do.
EDIT: Jus ttried it on mine. Had full UMTS signal and forced GSM and it worked!

I'm not in a position to test that at the moment (no 3G signal), however, doesn't that prevent all 3G facilities of the phone (i.e. video calls) from working?
Having said that, I can't think why I would want a video call, and I can always switch it back should I need to.
Cheers,
Steve.

Yes it does prevent all 3G features (and therefore extends battery life). Sorry, I didn't realise that this was not what you wanted to do. From your original post I thought you didn't want it to use UMTS at all.

Ideally, it was just the web browsing/internet access that I wanted to prevent switching to UTMS, but to be honest, I'm not sure I would miss video phoning - is there anything else I'm getting on 3G that I'll not get after making that change?
Cheers,
Steve.

As far as I'm aware, making voice calls on 3G is a little bit clearer than on GSM, but consumes more battery. So if you are unable to tell the difference between the two then you could fix it to GSM and save battery life.
However, don't forget that UMTS is vaunted as being 3 times faster than GPRS for internet use, so your browsing etc will slow down if you lock it into GSM/GPRS only mode. I bet this doesn't matter much for TomTom traffic though as I am sure it only uses small amounts of data. If you're happy with GPRS then go for it.

Yes, I'm aware of the speed difference between GPRS and UTMS. My main problem is that I use my Exec to update the football scores on my football club's website, but the home ground is in a marginal UTMS area, so it keeps switching on/off, and consequently takes much longer to update the score than if it just connected via GPRS.
I'll give these new settings a go, and if there are any unwanted side effects, I'll switch back.
Cheers,
Steve.

Having being in the know about 3G for some time now I'm saying that its virtually impossible to only use GSM for internet, but stay with 3G for vid calling.
Your best bet would be some 3rd party software for this as I don't think any 3G phone lets you do this.

Yes I agree Biohead. I don't even think third party software would help as the radio has to disconnect and then reconnect. So you can't do some stuff on GSM (like GPRS) and then some on UMTS (like Video calling) without disconnecting and reconnecting. Luckily for Mr Pritchard, he is not too bothered about video calling and so, hopefully, this will solve his problem.

o2 xda exec in the US, need some help.

I've been reading the Universal forum for days picking out tidbits of advice on what to do with my exec here in the US. I'd like some difinitive answers if anyone has them to these questions. (I use Cingular)
1. I currently live in massachusetts and my quad band razor gets [good] service in my apartement (seems to get data too). My NGage (tmobile branded) doesn't get service inside, but outside I get 3 to 4 bars. My new exec gets 1, maybe 2 bars outside, and mostly nothing inside. Every once in a while Ill pick up the cingular signal and then it fades before I can attempt to make a call. Can anyone explain this? Im not sure its just the 850 band discrepancy since the ngage is only dual band 900 & 1900mhz.
2. WHERE can I get the Cingular MMS and GPRS settings for my phone? I've found a few sites that I've been able to peacemeal together a working gprs connection using wap.cingular as my access point, but MAN is it slow! I get faster transfer speeds on the ngage! I think that Im not using the fastest available (what the phone can support and the network provides that are compatible) settings, so if anyone has any links that are better than the junk I've found, please post them, or a tutorial if you have time. Also I read that IMATE's extended rom has a configuration app that will auto configure GPRS and the correct GSM settings for a multitude of networks, would this solve my problem as in, does it work with Cingular US?
3. No one can agree as to whether the military in the US will give up the 2100 Mhz band, and since Cingular has begun deploying umts here on 1900mhz, whats the final story on the universal and UMTS? I see an equal number of posts and articles that say a software patch can allow the 1900mhz frequency to be used instead of the stock 2100, and I see another set of posts saying its hardware locked, and the universals 3G is and forever will be useless in the US.
4. Any US users please advise as to the most successful radio rom version, the stories about what does and doesn't work are mostly european. As we speak Im upping to the new o2 1.30 rom with radio version 1.09, that seems to be consistently considered the best rom abroad. Ironically the one person who commented from the US was reinstalling tmobile radio 1.11 because 1.09 sucked for him.
Thanks to the Experts for your help.

I hope this helps anyone of the number of readers who were interested in a response to this. I've done a bit of esearch and concluded that:
DO NOT TRY TO USE THIS PHONE WITH CINGULAR, unless you happen to live and/or exist in one of their 1900mhz locations. T Mobile USA is the way to go. while cingilar is phasing out 1900mhz in favor of their lower freqency but stronger 850mhz band, TMobile ispredominantly 1900mhz, except in very rural areas. They promise to continue to expand their 1900mhz network and build their massive wifi hotspot network to incorporate some of their "futuristic" seamless gsm over ip technology that is supposedly dominant in Germany. Don't see the big deal in that. However, I just moved to New Orleans, Louisiana yesterday and was able to test cingular and tmo side by side via 1900mhz coverage during the drive from Massachusetts. tmo was in full coverage most of the trip at 1900mhz. there were few places where I could get steady 1900 via cingular durin the drive, but to be fair, quad band cingular coverage was flawless until alabama, and then good again after the 20 minute stretch of nothing. tmo quad wasn't checked but is safe to say that the coverage is awesome in most metro areas. as long as you don't live on a farm you can safely use tmo and the universal together. I opted to keep my cingular voice (family) plan dueto my contract, but I did get a pretty sweet steal on tmo using a little trickery.
$30 a month for unlimited data + 500 text messages. no voice.
basically I signed up for the unlimited blackberry plan and requested access to internet2.voicestream.com AP for particular business software requirements. tmo was happy to oblige.
I had cingular unlimited data; and even when I had full service the connection was amzingly flaky. I even used my razr as a bt modem for my uni for a while to take advantage of the razrs quad band reception and data apeeds. slow and flaky, frequently failing dns lookups. tmo internet is sllow gprs but 3 to 4 times as responsive as cingular gprs. data lookup takes no more than 2 seconds, an large pages load in under 8 secons, including All pics. xda developers takes approx 4 seconds per pag to render via tmo. using cingular I couldn't make a followup post because lookup and rendering time were in the minutes, when the page loaded at all. Push via mail2web works great, not a single flaw so far. snce I can keep open the data connection and I'm not constantly redialing, my battery life has doubled. mail arrives within seconds of its arrival on the server, and I've never beeen happier with a device. agile messenger works great now too, running in the background all day without any hangups, hickups, or problems. just can't send push to talks because I can't map a ptt button. if anyone has any questions, just pm, post, or email me.

Configure Unlocked Universal for USA Cingular Medianet

First of all, allow me to apologize for posting this in the "General" area, rather than in the Universal specific area. I am, indeed, a bonehead.
I recently purchased an HTC Universal (my version: O2 XDA Exec--what can I say; I like black), and would like to configure it so that I can access Cingular's MediaNet service here in the U.S. I tried to follow the procedure for other similar phones, but as the Universal doesn't have exactly the same layout of connection options and so forth, I failed miserably.
Has anyone attempted to do this, and if so, how did you get it to work? I've gone as far as setting up the basic GPRS information, but I can't find any way to access a proxy server on the device. Any advice from anyone?
Doug

If you just change the My ISP tab, then you won't have the option to input a proxy server. Try adding a new connection and you should have the option to add a proxy

I was successfully able to set up the my XDA Exec on cingular. You need to create a new isp connection and a new dialup connection, for the dialup choose gprs,3g. Then for the access point put in wap.cingular. Thats it. Unfortunately the cingular network in the US does not support UMTS but in a few areas, and is not on teh same freqency as the UMTS in europe (2100mhz), the few test markets for cingular have it on the 850mhz band. The Universal does not support the 850mhz band at all. You'll find that the cingular gprs connection is extremely flakey. On top of that, unless you're lucky enough to live in a VERY RURAL Area (is that lucky?) Cingulars metro freqency of choice is 850mhz, so you'll get little service and tons of drops. TMobile is predominately 1900mhz, their GPRS is rock solid, (albet still as slow as gprs is) much faster than cingular and way more stable. Good luck.

Sess said:
I was successfully able to set up the my XDA Exec on cingular. You need to create a new isp connection and a new dialup connection, for the dialup choose gprs,3g. Then for the access point put in wap.cingular. Thats it. Unfortunately the cingular network in the US does not support UMTS but in a few areas, and is not on teh same freqency as the UMTS in europe (2100mhz), the few test markets for cingular have it on the 850mhz band. The Universal does not support the 850mhz band at all. You'll find that the cingular gprs connection is extremely flakey. On top of that, unless you're lucky enough to live in a VERY RURAL Area (is that lucky?) Cingulars metro freqency of choice is 850mhz, so you'll get little service and tons of drops. TMobile is predominately 1900mhz, their GPRS is rock solid, (albet still as slow as gprs is) much faster than cingular and way more stable. Good luck.
Click to expand...
Click to collapse
I got it connected. Yup, you're right; lots of drops. Since my contract is up in November, I might consider moving to TMobile. How is their nationwide coverage compared to Cingular? Better, worse, or about the same?
Thanks,
Doug

dougom said:
I got it connected. Yup, you're right; lots of drops. Since my contract is up in November, I might consider moving to TMobile. How is their nationwide coverage compared to Cingular? Better, worse, or about the same?
Thanks,
Doug
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Click to collapse
I wish I could be of more help on this one, but I've only used the universal in 5 major cities in teh US, New Orleans LA, Boston MA, Albuquerque NM, Amherst MA, and Metairie LA. Great coverage from tmo in all those areas, a little spotty in some larger buildings on teh uni, but on my Excalibur I get great coverage almost everywhere I've been, including my long drive from LA to FLorida (Ft Lauderdale). Almost guarantee that you'll get better results with TMO if you stick with the Uni, though there are now actually phones I would consider much better.

3g network bands

I am wondering if 3g networks require the phone to have 2 of the same bands or just one? for example, If I had a phone with 3g frequency of 1900/2100 would it still work with at&t or rogers (850/1900)?

3G would not work. Your phone needs to support whatever frequency is in the area. Lets say you are on AT&T, and AT&T uses 850 & 1900, but in your region they only use 850, then the phone must support 850 in order to properly use 3G signals.
For the most part there is no way to unlock frequencies or change frequencies on phones either.
Jason

So basically your saying that depending your location, it may or may not work?

Emulating a BTS for VoIP
@myrandex,
I wonder if it would be possible to have a USB 3G modem acting as a BTS.
I have 3cx on my ntb and, since I am roaming 95% of my time around Europe, I would like to set-up a USB modem to connect with my HTC Pro (which has the WM6VOIPFull installed) and hook-up to my 3cx via SIP and route my calls via Internet.
I can sort of do it now with WiFI, but battery drain and range really suck!
Right now I'm considering swapping pre-paid 3G SIM cards whenever I go to a new project; usually I stay 3-6 months - not enough to justify signing-up for a post paid (10.00 euros/month!!!!) and sure enough to break my bank account (*400 euros last month alone!*).
So PLEASE, I'm BLEEDING, if you know of any software that would make a USB or another htc (I have an old one around) to act as a BTS and stablish a data connection (with routing) to my hand set, that would ROCK!!!
I've been searching for 3G gateways and routers, but what they do is connect SIP-to-GSM/3G and vice-versa using the 3G network, not much help for me
So, the word is out! Let's see how many telco gurus are on xda (shhhh).
Thanks,
HZ

hzmonteiro said:
@myrandex,
I wonder if it would be possible to have a USB 3G modem acting as a BTS.
I have 3cx on my ntb and, since I am roaming 95% of my time around Europe, I would like to set-up a USB modem to connect with my HTC Pro (which has the WM6VOIPFull installed) and hook-up to my 3cx via SIP and route my calls via Internet.
I can sort of do it now with WiFI, but battery drain and range really suck!
Right now I'm considering swapping pre-paid 3G SIM cards whenever I go to a new project; usually I stay 3-6 months - not enough to justify signing-up for a post paid (10.00 euros/month!!!!) and sure enough to break my bank account (*400 euros last month alone!*).
So PLEASE, I'm BLEEDING, if you know of any software that would make a USB or another htc (I have an old one around) to act as a BTS and stablish a data connection (with routing) to my hand set, that would ROCK!!!
I've been searching for 3G gateways and routers, but what they do is connect SIP-to-GSM/3G and vice-versa using the 3G network, not much help for me
So, the word is out! Let's see how many telco gurus are on xda (shhhh).
Thanks,
HZ
Click to expand...
Click to collapse
I don't think it's possible to do what you're mentioning right now, but perhaps someone could create a hack if they really worked at it. To be honest that may not be worth the effort, the labor spent on creating such a system would probably outweigh the costs of getting the device with the correct bands
And, to answer the OP's questions, there are definitely plenty of users with devices that only support one of the 3G bands their carrier uses.
For example, a lot of people import the Telstra HD2 for use on AT&T's 850 band, even though it doesn't have 1900 support.
There are some cities where AT&T doesn't have 850 support, but a lot of recent 3G expansion/upgrades have resulted in additional 850 band usage, especially in markets like NYC.
You should check to see if AT&T uses 1900 in your general area, and any other place you intend on using the phone. Worst comes to worst, you'll still have EDGE...Some areas support both 850/1900 and devices toggle between them depending on which is less congested, etc. 850 tends to have better in-building reception, so if your device only supports 1900, and the network is spaced out for 850, you might not have as good 3G coverage in some areas, even if 1900 is technically supported.
All that in mind, if you're going to go with a "half-band" 3G solution, 850-only is probably better, as it correlates with AT&T's most recent 3G expansion/upgrades, and yields better indoor coverage when available.
Just a combination of my two cents and observations above. As always, YMMV.

@gsvnet
Nice reply to mkeras2, complements the one from myrandex very well.
Now to the BTS subject,
Actually, the idea of using a usb dongle doesn't seem so bad, these things have two way radio as any cell phone, it's just a matter of setting one as the end-point (broadcasting/polling) and the other (hand set) as client. I wouldn't mind having a tweak in the registry to set the radio to "allways connected" to a fixed "FakeNetID" and bypass PAP/CHAP authentication with the BCS (after all there would be no access to the GSM network, just to my PC/Internet/SIP Server) and I would only need data traffic, no messing around with CoDecs and the "hooking" of voice channels. A simple app could easily set/reset the registry, but I wonder if the radios would complete handshake and establish a connection.
I'm not sure about range with these radios without any high gain antennas and amplifiers, but I just need a few hundred meeters of access, pretty much as a good WiFi Router. And it would probably be perfectly legal as well (the devices are anyway).
After that it would be just routing.
BTW, I would love to get my hands on one of those new microcells. That's exactly what these things do, but with multiplexing and all the heavy security to authenticate and register to the GSM network.
They are being tested in the UK (I believe the first in Europe so far).
I live in Holland, but am currently in Luxembourg and have been recently working for 3+ months in Switzerland, LUX, NL and hoping around in Germany, Belgium, UK and Spain (vacations!!! ahhhh)...
So I'm curious to know what kind of plan Telcos will make available with the microcell.
If I am able to take it with me and plug it in whatever IP access point I have around, this would solve my roaming problem.
I don't mind paying to have access, don't get me wrong, but my NL plan gives me unlimited data access (national) for e10.00/month and I just went looking for a plan that WAS available from Vodafone UK (I use Vodafone NL), which allowed 5GB of data roaming in the EU for circa 50pounds/month, but it seems they no longer offer this plan.
During the last 2 months I was charged 300 and now almost 400 euros for roaming. As I said, I have a 60.00euro plan + 10.00 for unlimited national data.
I also know that in other EU countries you can get unlimited data plans for fair money as well, the problem is that I never know for how long I will stay in any given assignment/country. By the end of the year I would have some 5 or 6 annual subscriptions (still cheaper than roaming!) but I must have proof of residence in all those countries, bank account, etc, etc, etc... I don't LIVE in these places, I just work there for rather longer periods... and BTW, I'm a micro entrepreneur, so no way to push this onto "The Boss"... Thats me!
So I believe the charges imposed by Telcos for roaming are just not fair... Outrageous, actually.
I don't even mind paying for the Telco's CapEx (buying the microcell and using MY Internet connection), but at least I would have a sense of control and partnership/sponsorship.
And my mother told me to be a doctor... Decided to go into IT... Yeah!
Any info on these microcells and any ideas and buzz on Telcos' plans are very appreciated.
Cheers,
HZ