LTE starts now! What can consumers and service providers expect from LTE‾

Christian Fredrikson: Where W-CDMA/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 to user clicks.

In addition, 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.

How does LTE compare to other mobile technologies‾

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, which is in practice faster than today's HSPA by a factor of 10. Latency will be exceptionally low at 10-20 ms, 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 as well, 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 W-CDMA uses a 5-MHz spectrum chunk.

This gives tremendous deployment flexibility to service providers, allowing them to apply more bandwidth in hotspots with high-capacity demands, and down to 1.4-MHz blocks to achieve basic low-cost nationwide coverage. Furthermore, LTE protects existing W-CDMA 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, bypassing 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.

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/System Architecture Evolution (SAE) Trial Initiative involving vendors, chipset manufacturers and mobile service providers collaborating to validate the LTE ecosystem.

How is Nokia Siemens Networks supporting operator migration to LTE‾

Early this year, we launched our end-to-end LTE 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 software-definable BTS is the ideal upgrade path to LTE and offers all the energy saving, low-cost deployment and scalability benefits of the Flexi BTS family. It protects existing investments as service providers will be able to roll out the BTS with a W-CDMA/HSPA software release to support existing W-CDMA customers with a 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.

What have LTE test results revealed about the technology‾

In December 2007, Nokia Siemens Networks completed the world's first multi-user field trial in an urban environment using LTE.


In the demonstration, peak data rates of 160 Mbps were achieved.
The field trial was a 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. And with lessons learnt from W-CDMA development behind us and strong industry backing, we believes LTE will certainly live up to the expectations of the industry.