The huge popularity of
smartphones and tablet computers has pushed the need for mobile broadband
networks. Users find increasing value in mobile devices combined with a
wireless broadband connection. Users and new applications need faster access
speeds and lower latency while operators need more capacity and higher
efficiency. LTE is all about fulfilling these requirements. GSM made voice go
wireless, HSPA made initial set of data connections go wireless and now LTE
offers massive capabilities for the mobile broadband applications.
The first set of LTE
specifications were completed in 3GPP in March 2009. The first commercial LTE
network opened in December 2009. There were approximately 50 commercial LTE
networks by the end of 2011 and over 100 networks are expected by the end of
2012. The first LTE smartphones were introduced in 2011 and a wide selection of
devices hit the market during 2012.
Overall, LTE technology deployment has been a success story. LTE shows
attractive performance in the field in terms of data rates and latency and the
technology acceptance has been very fast. The underlying technology
capabilities evolve further which allows pushing also LTE technology to even
higher data rates, higher base station densities and higher efficiencies.
The history of
mobile communications has seen many competing radio standards for voice and for
data. LTE changes the landscape because all the existing radios converge
towards LTE. LTE is the evolution of not only GSM/HSPA operators but also CDMA
and WiMAX operators. Therefore, LTE can achieve the largest possible ecosystem.
LTE co-exists smoothly with the current radio networks. Most GSM/HSPA operators
keep their existing GSM and HSPA
radio networks running for long time together with LTE, and they also keep enhancing
the existing networks with GSM and HSPA evolutions. The LTE terminals are multimode
capable supporting also GSM and HSPA. The radio network solution is based on multi-radio
base station which is able to run simultaneously all three radios. Many
operators introduce multi-radio products to their networks together with LTE
rollouts to simplify the network management and to modernize the existing
networks.
The starting point for
CDMA andWiMAX operators is different since there is no real evolution for those
radio technologies happening. Therefore, CDMA and WiMAX operators tend to have
the most aggressive plans for LTE rollouts to get quickly to the main stream
3GPP radio technology to enjoy the LTE radio performance and to get access to
the world market terminals.
LTE Capabilities...........
Practical LTE data
rates in many cases are higher than the available data rates in fixed
Asymmetric Digital Subscriber Lines (ADSL). LTE has been deployed using number
of different bandwidths: most networks use bandwidth from 5 to 20MHz. If the
LTE bandwidth is smaller than 20MHz, the data rates scale down correspondingly.
LTE has been rolled out both with Frequency Division Duplex (FDD) and Time Division
Duplex) TDD variants. LTE has the benefit that both the FDD and TDD modes are highly
harmonized in standardization.
The end user
performance is also enhanced by low latency: the LTE networks can offer round
trip times of 10–20 ms. The LTE connections support full mobility including
seamless intra-frequency LTE handovers and inter-RAT (Radio Access Technology)
mobility between LTE and legacy radio networks. The terminal power consumption
is optimized by using discontinuous reception and transmission (DRX/DTX).
LTE also offers
benefits for the operators in terms of simple network deployment. The flat architecture
reduces the number of network elements and the interfaces. Self-Organizing Network
(SON) has made the network configuration and optimization simpler enabling faster
and more efficient network rollout.
LTE supports large
number of different frequency bands to cater the needs of all global operators.
The large number of RF bands makes it challenging to make universal LTE devices.
The practical solution is to have several different device variants for the
different markets. The roaming cases are handled mainly by legacy radios.
Initial LTE smartphones have a few different solutions
for voice: Circuit Switched Fallback (CSFB) handover from LTE to legacy radio
(GSM, HSPA, CDMA) or dual radio CDMAþLTE radio. Both options use the legacy circuit switched
network for voice and LTE network for data. The Voice over LTE (VoLTE) solution
with Voice over IP (VoIP) also started during 2012.
Radio technology Evolution...................
The radio technology
improvements need to be supported by the evolution of the underlying technologies.
The technology components – including mass storage, baseband, RF and batteries –
keep evolving and help the radio improvements to materialize. The size of the
mass
storage is expected to
have fastest growth during the next ten years which allows for storing more
data on the device and which may fuel data download over the radio. The memory
size can increase from tens of Gigabytes to several Terabytes. Also the digital
processing has its strong evolution. The digital processing power has improved
according to Moore’s law for several decades. The evolution of the integration
level will not be as easy as in earlier times, especially when we need to
minimize the device power consumption. Still, the digital processing capabilities
will improve during the 2010s, which allows for processing of higher data rates
and more powerful interference cancellation techniques. Another area of
improvement is the RF bandwidth which increases mainly because of innovations
in digital front end processing.
The terminal power
consumption remains one of the challenges because the battery capacity is
expected to have relatively slow evolution. Therefore, power saving features in
the devices will still be needed.
The technology evolution
is illustrated below;
With all the above said, Could Radio Technologies be Convergencing
Towards LTE?
