Some most important mobile phones Networks & Communication technologies describe in detail as under:-
GSM, 2 G
GSM (Global System for mobile) is the current standard mobile phones created early 1990.
Territory is divided into cells of a few hundred meters, each served by an issuer to short-range, station. Transmission technology is TDMA.
The original GSM used only the 900 MHz frequency band. It was extended to 1800 MHz and the original British DCS 1800 (Digital Cellular System) standard.
The GSM, CDMA, competitor is used in Europe, Latin America, Middle East and China, by 1.2 billion users.
The GSM family includes the GPRS (General Packet Radio Services), EDGE (Enhanced Data for GSM Evolution) and the 3GSM.
Known as 2 G (GSM 2nd generation), which corresponds to the passage for mobile telephony analog transmission (the large on-board phones in cars) digital transmission (and the emergence of mobile phones).
Over 70% of the French population is now equipped with a mobile phone.
CDMA
This is the standard cellular using CDMA technology that is deployed in the US and ASIA.
CDMA standard therefore competitor of GSM.
3 G evolution is the CDMA2000, whose Organizer is the 3GPP2, brother of the 3GPP.
WAP
Whenever there is a network of transport public digital information reliable and without holes, thought to be added to transport voice, data transport:
- First, in the form of Web pages easy to efficient telephone terminals: WAP.
- in IP forwarding to computers or PDAs.
WAP (Wireless Application Protocol) is a protocol set to view pages on a mobile phone.
The WAP has 5 VIP layers in a way similar to the OSI.
The application layer includes:
- WML (Wireless Markup Language) based on the XML family, similar to HTML page description language.
- WMLScript: a scripting language similar to JavaScript…
The GSM standard is sufficient to route voice in excellent conditions of quality. However, it is too slow to route Web pages in good conditions. GPRS has been implemented to allow the use of WAP.
i mode
i mode is not a communication protocol, but only a transfer content, competitor of WAP technology. It allows the transmission and consultation of multimedia content, as well as access to internet.
Using including HTML and non-XML, i-mode is simpler and lighter than the WAP. It is also less scalable and less powerful.
Created by NTT DoCoMo i-mode was adopted by Bouygues Telecom. However its i-mode terminals will be equipped with two-mode, compatible with both the Wap and i-mode browsers.
2.5 G GPRS
GPRS (General Packet Radio Service) is an enhanced version of the GSM standard. Voice is routed the classic GSM identically, but data is transferred by packets, 3 times faster. The strong point of GPRS is global compatibility with the old GSM network.
The arrival of UMTS making decidedly wait, GPRS is seen as a transitional stage and was baptized 2.5 G.
EDGE, 2.75 G
EDGE (Enhanced Data rate for GSM Evolution) is also an improved version of GSM. This is another economic step towards higher rates (this is why it is called 2. 75 G).
Its theoretical throughput is 250 kBps. It is standardized by ETSI.
Important actual throughput upload (for the user to the Internet), higher than the UMTS-R99 it interesting for data transfers. By download, on the other hand, EDGE does not support the comparison with UMTS-R99 and still less with HSPDA, more effective for future broadcasts of content.
France Telecom provides an EDGE service businesses since early 2005.
Bouygues Telecom plans to launch in may for businesses and end 2005 for individuals. Who do not yet reached its infrastructure capacity limits so it can add EDGE traffic without large investments. He then plans to jump to the UMTS HSDPA.
SFR has shown nothing be on EDGE.
An enhanced Edge version, GERAN (GSM/Edge Radio Access Network) is in preparation for the 3GPP.
UMTS, 3 G
2 Years late on the planned table, 3 G, 3rd generation telephony is finally available.
The 3 G must make much more important, now desirable rates for:
- viewing web pages on mobile telephone terminals,
- the videophone
- the transfer of data to computers and PDAs.
In Europe, the 3GPP (3d Generation Partnership Project) has chosen the UMTS W-CDMA standard that uses frequencies between 1900 and 2200 MHz and allows greater than 1 Mbps speeds (they should be capped at 128 kbps transmission and 384 kbps in reception).
Unfortunately several details have braked and still hamper the development of UMTS:
- the obligation to purchase a license from the State for each operator (several billion euros).
- the installation very high cost of new infrastructure (while GPRS and EDGE do require that the adaptation of existing infrastructure),
- slow takeoff compatible terminals UMTS Park (linked, it is true to the weakness of the offer).
The current version is UMTS-R99 (release 99). UMTS HSDPA should succeed him.
TDMA, CDMA, W-CDMA, TD-SCDMA
Multiple encoding and multiplexing technology put to point to ensure links to mobile. Their specific characteristics (cost, reliability, penetration…) have oriented and other choices.
- TDMA (Time Division Multiple Access) – French TDMA (multiple access to distribution in time). It is used in Europe for the GSM technology.
Every radio channel is sliced 8 time of 0.57 ms.
the frequencies used are 900 and 1800 MHz. The floor is compressed on a 22.8 kHz band that includes an encoding for the correction of errors.
Avoid fraudulent tapping of communications, the following means are used:
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Subscriber authentication – use a temporary identity (Temporary Mobile Station Identity = TMSI)
-communication encryption. - CDMA (Code Division Multiple Access)
This is an encoding of digitized information transmissions multiplexing technology to spread spectrum. It is used in the US and Asia in the standard of the same name.. - W-CDMA (Code Division Multiple Access – multiplexing by broad code Wide band) is a CDMA Variant used for third generation mobile telephony. The 3 G European UMTS standard is based on this technology.
- TD-SCDMA (Time Division Synchronous CDMA). This is the technology developed by the Chinese. More recent than CDMA and W-CDMA, she has an interest in performance and is pushed by the Chinese Government on its huge market.
4 G or 3 G II?
The first version of UMTS is called R99. If the UMTS doesn’t know a boom smash, is that it requires huge investments to finally not so distant rates of GPRS and EDGE.
Then already dream on in following developments which could be HSDPA.
HSDPA (High Speed Downlink Package Access) ensures the 2 Mbps rate initially provided with UMTS.
The HSDPA could appear as 2005 2006 in Europe and Japan.
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