One of the first mainstream cellcos to show an interest in the TDD bands within Europe's 2.6GHz spectrum for 4G is 3 Sweden, which is looking to buy these licenses from existing holder Intel.
European operators have so far remained ambivalent about the TDD spectrum licenses that are being auctioned alongside FDD in the 2.6GHz band. The unpaired spectrum is well suited to web and data services, but there are remaining issues about possible interference with FDD networks, and TD-LTE remains largely unproven.
However, a recent Rethink Research study found that most cellcos are interested in the TDD bands, as a way to increase their total spectrum horde, but regard it as a basis for a second phase 4G rollout, probably after 2013.
In The Netherlands, the TDD license went unsold in the recent auction, and in other countries, this spectrum has gone for a lower price or to new entrant carriers, particularly those using the first TDD 4G standard, Wimax.
It was for this reason that Intel purchased Sweden's TDD license, looking to establish a beachhead for its favored mobile broadband technology. Now, though, Intel spokesperson Camilla Tornblom says the firm has re-evaluated the purchase it made in 2008 and believes it makes financial sense to sell its frequencies to 3.
In Scandinavia, 3 has already announced plans to launch LTE services in Sweden and Denmark next year, and already has some 2.6GHz FDD spectrum in place. It is unclear what it will pay Intel for the licenses it acquired for $26 million two years ago.
In Denmark's auction earlier this year, 3 was the surprise winner of the largest tranche, gaining 2 x 10MHz of FDD spectrum as well as 25MHz of TDD. Other winners were TDC, Telenor and Telia.
The pattern of 3's purchases suggest that it is looking to stockpile TDD as well as FDD frequencies at an early stage, rather than relying on returning to the market at phase two to buy TDD licenses from third parties, as some cellcos are planning.
This could give 3 superior capacity in some markets and, despite the complexities of creating a TDD/FDD system, the potential to build different networks for different services. Some players have suggested that operators might use TDD spectrum to support femtocells, for indoor penetration and urban capacity, while reserving FDD for more conventional macrocells.
When Intel invested in the licenses, it was expected to form a partnership with an operator that would build out a Wimax network - an approach similar to Qualcomm's in India.
However, Sweden has since become a hotbed of LTE, hosting the world's first network based on the technology, so the country may no longer be attractive to Intel for promoting its own platform.