re: "So I ask, Is the worldwide breakdown of FDD to TDD actually 1:10?"
It's probably even more lopsided that that, depending whether you consider all legacy spectrum, or just new/future spectrum. FDD (and paired spectrum blocks--one for "upstream transmissions" and one for "downstream"), with space in between is an artifact of history; there wasn't much in the way of TDD offerings in the past.
Under "technology neutrality," regulators are not supposed to continue to slant the playing field to favor FDD, for new spectrum allocations. Equal-opportunity spectrum has to allow both, and has to avoid rules that slant the operator's decision toward FDD. But there are co-existence/interference issues with TDD and FDD adjacent to each other.
Whether an operator elects to deploy TDD or FDD should only depend on which one best suits the services they intend to offer, not on regulatory penalties if TDD is elected. Simplistically speaking, TDD is more efficient for highly variable upstream/downstream load ratios in the service being offered, and FDD is more efficient for more balanced loads because the spectrum is split into 2 equal-sized parts.
Wimax has (or will have) a mix of TDD and FDD profiles, but Wimax does not currently have a profile for 700MHz. There are other candidate technologies for the 700MHz spectrum that utilize TDD, so it isn't just an issue of making room for Wimax.
The 700MHz spectrum that will be up for auction in the US has a mix of paired blocks and unpaired (stand-alone) blocks. The lower 700MHz is all 6MHz blocks (single 6MHz or paired giving 12 total). The upper 700MHz is TBD, and may be a 5MHz pair and a 10MHz pair, a 5MHz pair and an 11MHz pair, three 5.5MHz pairs, or possibly some other permutation. There are a range of reasons different players want different configurations, but under the current rules, any of these blocks can be either TDD or FDD. But the operational rules don't really address this head-on.
Separate from the operational rules are the auction rules (which are yet to be set). Which blocks, and what geographic size of blocks can be aggregated in bids, and how to prevent large players from killing new entrant plans by high-bidding a single geographic block that essentially breaks the new entrants business plan, are all things under consideration.
PS the "TV white space" spectrum that we've posted about here many times, and which has a continuous stream of articles written about it, is mutually exclusive from the 700MHz spectrum. There are still way too many articles that talk about them as one in the same. The white space spectrum is directly *below* and not overlapping with the (upper and lower) 700MHz spectrum. |
