Long Term Evolution, or LTE, promises true broadband speeds, bringing advanced data applications to mobile screens without the waiting. One of the most important new mobile technology launches since 3G is coming fast.
Where WCDMA/HSPA radio technologies have shown us the possibilities, LTE will make them fly. With LTE, end-users will experience mobile broadband like never before. Browsing, email, video sharing, music downloads and many more applications will respond immediately when the user clicks.
Even better, the more efficient and flexible use of spectrum and network simplification that LTE brings will mean a significantly lower cost per gigabyte. Service providers will be able to offer flat-rate ‘all-you-can-eat’ tariffs, while still maintaining profitability.
Super-fast performance
As the optimal evolution of 3GPP and 3GPP2 mobile technologies, LTE offers peak data rates of 173 Mbps in the downlink and 58 Mbps in the uplink, in practice faster than today’s HSPA by a factor of ten. Latency will be exceptionally low at 10-20ms, considerably boosting the end-user experience of services such as gaming and browsing, as well as the performance of true real-time applications such as VoIP.
LTE has higher spectral efficiency than HSPA, so service providers can squeeze more data into their available spectrum. In addition, LTE uses spectrum in widths selectable from 1.4 MHz up to a whopping 20 MHz, whereas WCDMA uses a 5 MHz spectrum chunk.
“This gives tremendous deployment flexibility. Service providers can apply more bandwidth in hotspots with high capacity demands, and down to 1.4 MHz blocks to achieve basic low cost nationwide coverage,” explains Kai Sahala, Head of Strategic Solution Sales in Radio Access, Nokia Siemens Networks. “Furthermore, LTE protects existing WCDMA investments by extensively re-using sites and network elements.”
The high performance and low costs are also due to LTE’s network-simplifying 2-node flat architecture for user data, in which the base station is connected directly to one element in the core network, by-passing control plane elements. Nokia Siemens Networks has a head start in flat architecture with its I-HSPA technology that already uses the same architecture that LTE employs.
The easy upgrade option
Early 2008 saw the launch of the Nokia Siemens Networks LTE end-to-end system comprising the software-definable Flexi Multimode Base Station (BTS), Flexi Mobile Network Gateway and MME, bringing LTE a step closer to commercial deployment. The new BTS offers all the energy saving, low cost deployment and scalability benefits of the Flexi BTS family.
“The software-definable Flexi Multimode BTS is the perfect upgrade path to LTE,” says Sahala. “Service providers can roll out the BTS with the WCDMA/ HSPA software release to support existing WCDMA customers with a really state of the art high power BTS. Then, when LTE devices become available and the service is ready to launch, they only need to apply a quick and easy software upgrade to achieve full LTE functionality.”
Clearly, LTE offers the best evolutionary path for service providers to upgrade their mobile broadband. The technology also carries wide industry backing with the LTE/SAE (System Architecture Evolution) Trial Initiative involving vendors, chipset manufacturers and mobile service providers collaborating to validate the LTE ecosystem.
“The lessons of WCDMA development have been learned and with such strong industry backing, LTE will live up to all the industry’s expectations,” concludes Sahala.
Tests a success
In December 2007, Nokia Siemens Networks announced that it had completed the world’s first multi-user field trial in an urban environment using LTE. In the demonstration, peak data rates of over 100 Mbps were achieved.
The field trial was a world first since it was conducted in a real urban outdoor environment with multiple users using the new 2.6 GHz spectrum. It confirms that LTE performance requirements can be met using 3GPP standardized technologies.
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