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A tale of two technologies: refarming and RF sharing bolster Japanese LTE

This blog is by Sandra Pierini at Nokia Networks.Twitter: @sandra_pierini

We often say that spectrum is the most important and valuable resource for operators. It’s also the scarcest. If you have less frequency than other operators, you’re at an immediate competitive disadvantage. Let me tell you a story that illustrates this.


Japan is one of the world’s most advanced mobile broadband markets with LTE network performance at the heart of the competitive arena. When Softbank Mobile (SBM) launched its LTE services a few years ago, they did not have a dedicated spectrum for LTE.

When spectrum is scarce…

As Japan is a world leader in the wireless networks arena, there was no 2G network available for re-farming. SBM had already switched off their second generation networks a few years ago.

The only solution was therefore to take some of SBM’s existing 2.1 GHz spectrum used for WCDMA/HSPA and refarm it to carry LTE services. Furthermore, to enhance customer satisfaction, SBM worked to increase LTE allocation by refarming 2.1GHz to 10MHz and 15MHz. The trick was to do this without degrading the quality of the WCDMA/HSPA mobile broadband experience for subscribers.

Fortunately, at Nokia Networks we have considerable experience with well over 125 refarming references, which makes us the market leader in this area. Our Single RAN Advanced solution is leveraging highly effective radio frequency (RF) sharing capabilities in the Flexi Multiradio 10 Base Station. This means that Flexi radio modules can be configured to run multiple radio access technologies on the very same hardware and antenna in parallel.

With SBM we’ve refarmed thousands of sites at 2.1 GHz to run LTE in 5 MHz, 10 MHz and 15 MHz allocations. All the sites use RF sharing to support WCDMA/HSPA and LTE from the same base station. The result has been spectacular, boosting LTE coverage and capacity to give subscribers a more enjoyable LTE experience, without any loss of WCDMA/HSPA network quality.

…and other proven opportunities

SBM will also be capitalizing on the opportunity to apply RF sharing to existing WCDMA/HSPA sites in the dedicated LTE spectrum of 900 MHz band and thereby enable co-location of LTE and WCDMA/HSPA in this valuable part of the spectrum. They will benefit from the experience of successful refarming with 2.1GHz. All this will be achieved with an extremely compact and cost-effective site solution, a single base station in which hardware is shared by two technologies and in two different bands.

Both approaches make use of our Single RAN Advanced* solution that enables operators to evolve networks to multi-band operation and protect their existing investments, while also simplifying network operations to reduce costs. Likewise, RF sharing is proving to be a powerful way for operators across the globe to use their spectrum more efficiently.

This is certainly a tale with a happy ending!

To share your thoughts on our tale of two technologies, join the discussion with @nokianetworks using #NetworksPerform #HSPA #LTE #spectrum #mobilebroadband.

*Single RAN is finding favor among most operators. Vodafone New Zealand, for example, is an advocate – click here to see a video in which Sandra Pickering, Chief Technology Officer, and Tony Baird, Chief Network Officer, both of Vodafone New Zealand, explain why.

Sandra Pierini

About Sandra Pierini

Sandra Pierini is responsible for Nokia Networks’ product marketing, strategy and content development for global Public Safety, Refarming and End-to-End Quality of Service differentiation. During her experience in telecommunications, she has covered positions spanning from product management and business development to sales. Sandra has her MBA from MIP University of Milano and Master's degree in Electronic Engineering from the University of Pisa. You can find her in Twitter here: @Sandra_Pierini.

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