| Mobile telephony standards | ||||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| 0G (radio telephones) | ||||||||||||
| 1G |
| |||||||||||
| 2G |
| |||||||||||
| 2G transitional (2.5G, 2.75G) |
| |||||||||||
| 3G (IMT-2000) |
| |||||||||||
| 3G transitional (3.5G, 3.75G, 3.9G) |
| |||||||||||
| 4G (IMT-Advanced) |
| |||||||||||
| 5G |
| |||||||||||
| Related articles | ||||||||||||
1981 analog (1G)
1993 digital (2G) transmission in 1992
GSM (Global System for Mobile Communications: originally from Groupe Spécial Mobile) is the most popular standard for mobile telephonysystems in the world. The GSM Association, its promoting industry trade organization of mobile phone carriers and manufacturers, estimates that 80% of the global mobile market uses the standard.[1]
GSM also pioneered low-cost implementation of the short message service (SMS), also called text messaging, which has since been supported on other mobile phone standards as well. The standard includes a worldwide emergency telephone number feature (112).[4]
General packet radio service (GPRS) is a packet oriented mobile data service available to all users of the 2G cellular communication systems global system for mobile communications (GSM), as well as in the 3G systems. In 2G systems, GPRS provides data rates of 56-114 kbit/second [1]
GPRS data transfer is typically charged per megabyte of traffic transferred, while data communication via traditional circuit switching is billed per minute of connection time, independent of whether the user actually is using the capacity or is in an idle state. GPRS is a best-effort packet switched service, as opposed to circuit switching, where a certain quality of service(QoS) is guaranteed during the connection for non-mobile users.
2G cellular systems combined with GPRS are often described as 2.5G, that is, a technology between the second (2G) and third (3G) generations of mobile telephony[2]. It provides moderate speed data transfer, by using unused time division multiple access (TDMA) channels in, for example, the GSM system. Originally there was some thought to extend GPRS to cover other standards, but instead those networks are being converted to use the GSM standard, so that GSM is the only kind of network where GPRS is in use. GPRS is integrated into GSM Release 97 and newer releases. It was originally standardized by European Telecommunications Standards Institute (ETSI), but now by the 3rd Generation Partnership Project(3GPP)[3][4].
GPRS was developed as a GSM response to the earlier CDPD and i-mode packet switched cellular technologies.
2002, (3G) multi-media support, spread spectrum transmission and at least 200 kbit/s
4G, which refers to all-IP packet-switched networks, mobile ultra-broadband (gigabit speed) access and multi-carrier transmission.[citation needed] Pre-4G technologies such as mobile WiMAX and first-release 3G Long term evolution (LTE) have been available on the market since 2006[1] and 2009[2][3][4] respectively.
A 4G system is expected to provide a comprehensive and secure all-IP based solution where facilities such as IP telephony, ultra-broadband Internet access, gaming services and streamed multimedia may be provided to users.
This article uses 4G to refer to IMT-Advanced (International Mobile Telecommunications Advanced), as defined by ITU-R..
An IMT-Advanced cellular system must have target peak data rates of up to approximately 100 Mbit/s for high mobility such as mobile access and up to approximately 1 Gbit/s for low mobility such as nomadic/local wireless access, according to the ITU requirements. Scalable bandwidths up to at least 40 MHz should be provided.[5][6]
In all suggestions for 4G, the CDMA spread spectrum radio technology used in 3G systems and IS-95 is abandoned and replaced by frequency-domain equalization schemes, for example multi-carrier transmission such as OFDMA. This is combined with MIMO (i.e., multiple antennas(Multiple In Multiple Out)), dynamic channel allocation and channel-dependent scheduling.
WiMAX
The Mobile WiMAX (IEEE 802.16e-2005) mobile wireless broadband access (MWBA) standard is sometimes branded 4G, and offers peak data rates of 128 Mbit/s downlink and 56 Mbit/s uplink over 20 MHz wide channels. The IEEE 802.16m evolution of 802.16e is under development, with the objective to fulfill the IMT-Advanced criteria of 1 Gbit/s for stationary reception and 100 Mbit/s for mobile reception.[8] The world's first commercial mobile WiMAX service was opened by KT in Seoul, South Korea on 30 June 2006.[1]
LTE-service was opened in the two Scandinavian capitals Stockholm (Ericsson system) and Oslo (a Huaweisystem) on the 14 December 2009, and branded 4G. The user terminals were manufactured by Samsung [2] Most major mobile carriers in the United States and several worldwide carriers have announced plans to convert their networks to LTE beginning in 2011.
4G is being developed to accommodate the quality of service (QoS) and rate requirements set by further development of existing 3G applications like mobile broadband access,Multimedia Messaging Service (MMS), video chat, mobile TV, but also new services like HDTV. 4G may allow roaming with wireless local area networks, and may interact with digital video broadcasting systems.
The 4G working group[clarification needed] has defined the following as objectives of the 4G wireless communication standard:
- Flexible channel bandwidth, between 5 and 20 MHz, optionally up to 40 MHz.[6]
- A nominal data rate of 100 Mbit/s while the client physically moves at high speeds relative to the station, and 1 Gbit/s while client and station are in relatively fixed positions as defined by the ITU-R,[11]
- A data rate of at least 100 Mbit/s between any two points in the world,[11]
- Peak link spectral efficiency of 15 bit/s/Hz in the downlink, and 6.75 bit/s/Hz in the uplink (meaning that 1 Gbit/s in the downlink should be possible over less than 67 MHz bandwidth)
- System spectral efficiency of up to 3 bit/s/Hz/cell in the downlink and 2.25 bit/s/Hz/cell for indoor usage.[6]
- Smooth handoff across heterogeneous networks,[12]
- Seamless connectivity and global roaming across multiple networks,[13]
- High quality of service for next generation multimedia support (real time audio, high speed data, HDTV video content, mobile TV, etc.)[13]
- Interoperability with existing wireless standards,[14] and
- An all IP, packet switched network.[13]
- Femtocells (home nodes connected to fixed Internet broadband infrastructure)
source: http://en.wikipedia.org/wiki/4G ,http://en.wikipedia.org/wiki/3G , http://en.wikipedia.org/wiki/2G , http://en.wikipedia.org/wiki/1G , http://en.wikipedia.org/wiki/0G , http://en.wikipedia.org/wiki/GSM , http://en.wikipedia.org/wiki/General_Packet_Radio_Service ,
