4G is being developed to accommodate the quality of service
(QoS) and rate requirements set by forthcoming applications like
wireless broadband access, Multimedia Messaging Service (MMS),
video chat, mobile TV, HDTV content, Digital Video Broadcasting
(DVB), minimal service like voice and data, and other streaming
services for "anytime-anywhere". The 4G working group has defined
the following as objectives of the 4G wireless communication
standard:
* A spectrally efficient system (in bits/s/Hz and
bits/s/Hz/site),[2]
* High network capacity: more simultaneous users per
cell,[3]
* 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,[1]
* A data rate of at least 100 Mbit/s between any two points in
the world,[1]
* Smooth handoff across heterogeneous networks,[4]
* Seamless connectivity and global roaming across multiple
networks,[5]
* High quality of service for next generation multimedia support
(real time audio, high speed data, HDTV video content, mobile TV,
etc)[5]
* Interoperability with existing wireless standards,[6] and
* An all IP, packet switched network.[5]
In summary, the 4G system should dynamically share and utilise
network resources to meet the minimal requirements of all the 4G
enabled users.
According to the 4G working groups, the infrastructure and the
terminals of 4G will have almost all the standards from 2G to 4G
implemented. Although legacy systems are in place to adopt existing
users, the infrastructure for 4G will be only packet-based
(all-IP). Some proposals suggest having an open platform where the
new innovations and evolutions can fit. The technologies which are
being considered as pre-4G are the following: Flash-OFDM, WiMax,
WiBro, iBurst, 3GPP Long Term Evolution and 3GPP2 Ultra Mobile
Broadband. One of the first technology really fullfilling the 4G
requirements as set by the ITU-R will be LTE Advanced as currently
standardized by 3GPP. LTE Advanced will be an evolution of the 3GPP
Long Term Evolution. Higher data rates are for instance achieved by
the aggregation of multiple LTE carriers that are currently limited
to 20MHz bandwidth. The above is from Wikipedia. To read the full
article, see the page link, further down this page, listed under
"Related Links."
