What is LTE/HSPA+/4G?
LTE (Long Term Evolution) is a standard which lays claim to
being the very next generation of mobile networks – in effect, '4G'.
The LTE standard - sometimes referred to as
'Super 3G '- is specified to offer data rates approaching 100 Mbit/s in the
downlink. However, LTE technical demonstrations have already [2009] shown that data
rates of up to 160 Mbit/s are possible. A look through the original
specifications proposed by the ITU (International Telecommunications Union) for
LTE shows there's supposed to be support for 1 Gbit/s in hot spots within LTE.
The vendors have gone a bit quiet on that score, however.
It is expected that a wide range of devices will carry embedded LTE modems. The
list should include notebooks; ultra-portables; cameras; camcorders; and even
some desktop computers. This is besides the normal ranges of mobile handsets and
wireless PDAs. LTE can operate in such a wide range of different frequencies -
from 1.4 MHz to 20 MHz - that any country in the world will be able to deploy
it.
LTE's chief competitor is Mobile WiMax - the high speed variant of Wi-Fi - which
is heavily promoted by the likes of Intel. Sprint in the USA has expressed its
support for WiMax as a '4G' technology, for instance. Mobile WiMAX employs very
similar techniques to HSPA (the precursor to LTE), which makes its performance
comparable in some areas. The two technologies have similar peak data rates and
spectral efficiency, for example. However, there are key differences in areas
such as uplink bit rates and network coverage. A key factor in LTE's favour is
going to be economy of scale. That's because virtually all of the world's
leading mobile operators – including China Mobile – have thrown their weight
behind LTE.
There's still life left in 3G, however. Vodafone,
for example, is currently trialling a further standard called HSPA+. Unlike LTE
or Mobile WiMax, HSPA+ works over existing networks. It is claimed to be capable
of supporting download speeds of up to16 Mbit/s – compared to the current top
speed of 7.2 Mbit/s which Vodafone can already off (through regular HSPA).
A prime impetus towards 4G will be network
saturation. Not only will increasing numbers of people be attempting to access
information via 3G (rather than via fixed lines), there will also be a growing
number of 'bandwidth hungry' services and applications channelled via 3G. Unless
the situation is quickly rectified, many existing mobile phone networks just
won't be able to cope with the traffic.
Take, for example, bandwidth hungry applications such as the social networks.
Their members will be attempting to upload not only their cameraphone snaps but
also their videos and music files to their own personal pages. These
'user-generated' content files are highly data intensive. Furthermore, 4G
beckons towards a whole host of new services such as interactive TV, HD (high
definition) video (such as movies) plus real-time gaming. They'll all consume
large amounts of the bandwidth which 3G data networks will struggle to offer.
4G also stands a good chance of becoming the
dominant broadband technology. Ericsson, for example, estimates that of the 1.8
billion people who will have access to broadband by 2012, two thirds of those
(1.2 billion) will be mobile broadband users. In many regions, mobile broadband
will be the only form of high speed data access to the Internet that there is.
So, LTE is not only designed to increase network capacity it also aims to be
able to compete with rival, fixed forms of broadband.
Curiously, the first country to operate a
commercial LTE network should be Sweden. Nordic mobile operator, TeliaSonera,
has commissioned both China's Huawei and Sweden's Ericsson to supply the
equipment for a LTE network that should be operating in Oslo by 2010. It's a
historic event as, until now, Japan's NTT DoCoM has always led the way in
cellular technology – offering the first natioanl 3G network, for example.
Meanwhile, Motorola has thrown open its factory in Swindon, England to allow
mobile operates to test LTE calls(with data streaming) using a prototype LTE
device operating in the 2.6 GHz spectrum band.
The most likely outcome is that LTE, Mobile WiMax
and 3G/HSPA+ will all happily co-exist. Crucially, however, LTE offers the chance of
offering a truly global mobile telephone network – something which 3G can't
offer – given its near-universal support from mobile operators.
