General Packet Radio Service (GPRS) is a mobile data service available to users of GSM mobile phones. It is often described as "2.5G", that is, a technology between the second (2G) and third (3G) generations of mobile telephony. It provides moderate speed data transfer, by using unused TDMA channels in the GSM network. The theoretical limit for packet switched data is approx. 171.2 kbit/s. A realistic bit rate is 30–70 kbit/s. A change to the radio part of GPRS called EDGE allows higher bit rates of between 20 and 200 kbit/s. (from Wikipedia)
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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
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.
What is GSM?
GSM (Global System for Mobile Communications, originally Groupe Spécial Mobile), is a standard developed by the European Telecommunications Standards Institute (ETSI) to describe protocols for second-generation (2G) digital cellular networks used by mobile phones. As of 2014 it has become the default global standard for mobile communications - with over 90% market share, operating in over 219 countries and territories.[2]
2G networks developed as a replacement for first generation (1G) analog cellular networks, and the GSM standard originally described a digital, circuit-switched network optimized for full duplex voice telephony. This expanded over time to include data communications, first by circuit-switched transport, then by packet data transport via GPRS (General Packet Radio Services) and EDGE (Enhanced Data rates for GSM Evolution or EGPRS).
GSM carrier frequencies
GSM networks operate in a number of different carrier frequency ranges (separated into GSM frequency ranges for 2G and UMTS frequency bands for 3G), with most 2G GSM networks operating in the 900 MHz or 1800 MHz bands. Where these bands were already allocated, the 850 MHz and 1900 MHz bands were used instead (for example in Canada and the United States). In rare cases the 400 and 450 MHz frequency bands are assigned in some countries because they were previously used for first-generation systems.
Most 3G networks in Europe operate in the 2100 MHz frequency band. For more information on worldwide GSM frequency usage, see GSM frequency bands.
Regardless of the frequency selected by an operator, it is divided into timeslots for individual phones. This allows eight full-rate or sixteen half-rate speech channels per radio frequency. These eight radio timeslots (or burst periods) are grouped into a TDMA frame. Half-rate channels use alternate frames in the same timeslot. The channel data rate for all 8 channels is 270.833 kbit/s, and the frame duration is 4.615 ms.
The transmission power in the handset is limited to a maximum of 2 watts in GSM 850/900 and 1 watt in GSM 1800/1900.
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Source: Wikipedia
For more information about this subject, visit this link on wikipedia
UMTS stands for Universal Mobile Telecommunication System. This system is used to handle high data traffic. It is a 3G networking standard which is used throughout much of the world as an upgrade to existing GSM mobile networks. UMTS makes use of WCDMA technology that shares much with CDMA networks used throughout the world, though it’s not compatible with them.Universal Mobile telecommunication system (UMTS) is one of the third generation (3G) mobile technologies, that uses WCDMA as the underlying standard and is standardized by the Third Generation Partnership Project (3GPP) and represents the European answer to International Telecommunication Union\’s (ITU) International Mobile Telecommunication 2000 necessities for 3G cellular radio systems.
UMTS supports transfer of data rate up to 1920 Kbit/s, but in a heavily loaded real-world system, typical users can expect performance of around 384 Kbit/s. But this is much greater than the 14.4Kbit/s of a single GSM error corrected data channel or multiple 14.4 Kbit/s channels in HSCSD, and offer the primary prospect of practical inexpensive access the World Wide Web on a mobile device and for the general use of MMS.
Thanks for this article, his commercial calling IS 3G, 3G+ for HSPA, for information.
Hello guys, so sry for my English, because i`m from Ukraine. I have trouble with GSM.. I can`t use this standart, only WCDMA\LTE.When I tap on the "Only GSM" phone don`t registered.. I think it`s error in the Service Menu..
WCDMA (Wide Band Code Division Multiple Access) or UMTS (Universal Mobile Telephone System) – this standard has been developed to accept higher rates up to 2 Mbps (to 2 Mbps (local area access) or 384 Kbps (wide area access)) allowing to surf the net, use the videophone, download video…WCDMA is a third-generation (3G) mobile wireless technology.
http://cellphones.about.com/od/cell_phone_glossary/g/wcdma.htm
To obtain higher speeds, HSDPA (high speed downlink packet access) was introduced in version 5 of the WCDMA (3GPP). HSDPA allows data rates up to 10 Mbps (and 20 Mbps for MIMO (Multiple Input Multiple Output)).
http://www.wisegeek.com/how-do-i-choose-the-best-hsdpa-phones.htm
GSM/WCDMA (WCDMA preferred) – The GSM phone can use both 2G and 3G data communication and when signal strength is low 3G is favored more.
GSM only – The GSM phone use only 2G data communication. When the 2G signal is too low you get nothing.
WCDMA only – The GSM phone use only 3G data communication. When the 3G signal is too low you get nothing.
* WCDMA is the standard that most GSM carriers moved to when upgrading to 3G. Parts of the WCDMA standard are based on GSM technology. WCDMA networks are designed to integrate with GSM networks at certain levels. Most WCDMA phones include GSM as well, for backward compatibility. So you can leave it as it is.
Joku1981 said:
WCDMA (Wide Band Code Division Multiple Access) or UMTS (Universal Mobile Telephone System) – this standard has been developed to accept higher rates up to 2 Mbps (to 2 Mbps (local area access) or 384 Kbps (wide area access)) allowing to surf the net, use the videophone, download video…WCDMA is a third-generation (3G) mobile wireless technology.
http://cellphones.about.com/od/cell_phone_glossary/g/wcdma.htm
To obtain higher speeds, HSDPA (high speed downlink packet access) was introduced in version 5 of the WCDMA (3GPP). HSDPA allows data rates up to 10 Mbps (and 20 Mbps for MIMO (Multiple Input Multiple Output)).
http://www.wisegeek.com/how-do-i-choose-the-best-hsdpa-phones.htm
GSM/WCDMA (WCDMA preferred) – The GSM phone can use both 2G and 3G data communication and when signal strength is low 3G is favored more.
GSM only – The GSM phone use only 2G data communication. When the 2G signal is too low you get nothing.
WCDMA only – The GSM phone use only 3G data communication. When the 3G signal is too low you get nothing.
* WCDMA is the standard that most GSM carriers moved to when upgrading to 3G. Parts of the WCDMA standard are based on GSM technology. WCDMA networks are designed to integrate with GSM networks at certain levels. Most WCDMA phones include GSM as well, for backward compatibility. So you can leave it as it is.
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I know it`s all.. I can`t connect to 2G