back to article TDD LTE gaining momentum in 4G push, says ZTE

The Frequency Division Duplex (FDD) flavour of LTE will face increasing competition in favour of Time Division Duplexing (TDD), according to Chinese telecoms infrastructure giant ZTE. Far more operators currently have FDD networks either in operation or trialing than TDD, as can be seen on this handy interactive map. FDD's …

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Unhappy

lack of paired spectrum

Its a fair comment considering how much demand for spectrum there is forecast to be for mobile use and the lack of paired spectrum that seems to be available for international harmonisation in the near future. Maybe TDD will win just because of this (lack of) availability.

My uneducated feeling wonders if that killing off FDD now by ZTE becomes a self fulfilling prophecy. What do the Apples and Samsungs say about this? Though if the asymmetrical demands of mobile data consumption eg Lolcats galore on youtube continue, FDD will be a waste of good spectrum.

Sad face as my boss didn't send me the world mobile congress in Barcelona

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Silver badge

What about power?

Having more radio resource blocks available means you can use more. So you could use simpler modulation schemes which can worse signal- to noise ratios enabling you to use less signal meaning less power.

TDD on the other hand has serious problems as you need to manage the timing very accurately and you'll always have dead times when you need between sending and receiving.

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Gold badge

Chicken and the egg?

"What do the Apples and Samsungs say about this?"

I don't care what Apple has to say; surprisingly I found my (CDMA/EVDO/LTE) Samsung Stratosphere actually has no Qualcomm hardware in it (the LTE chip is Samsung, and the CDMA/EVDO chip is Via Technologies.). But, Qualcomm in fact makes loads of chips, if they support TDD in 900/1800/2100 (Europe) and 700/850/1900/AWS (US) then so many phone makers just drop in a Qualcomm solution that phone makers could naturally follow, it'd be essentially a zero-cost option to support both FDD and TDD compared to now.

Anyway, any take off of TDD would necessitate changes of regulations on these bands so the cell co can use the band how they wish, as opposed to the current situation of having particular uplink and downlink bands. If that happens, indeed TDD should help use upstream spectrum that is likely rather wasted at present. At that point, the big question is, will carriers (outside China) actually decide to use TDD instead of FDD? That I do not know.

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