Talk:Space–time block code

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[edit] Decoding

The "Decoding" section in the "Space Time Block Code" section contains a mistake:

"One particularly attractive feature of STBCs is that maximum likelihood decoding can be achieved at the receiver with only linear processing."

The sentence is wrong because only ORTHOGONAL STBCs enjoy this feature. Quasi-orthogonal STBCs cannot use this advantage, and their loss in performance (as long as linear decoding is concerned) is also due to this. Therefore also in the Quasi-orthogonal STBCs section this point (ie: impossibility to perform ML detection with linear processing) should be pointed out.

147.162.2.222 09:58, 30 December 2005 (UTC) Francesco Rossetto (franzRoss@gmail.com) 147.162.2.222 09:58, 30 December 2005 (UTC)

[edit] 3 transmit antennas

Why does the "Rate 1/2" code for 3 transmit antennas contain an S4? This doesn't make sense. It also appears to be a Rate 3/8 block code.—The preceding unsigned comment was added by 130.207.237.68 (talk • contribs) 18:16, 20 November 2006 (UTC)

Well, that's just the way that STBC works. It distributes 4 symbols over 3 antennas, and does not transmit them all in each time-slot. There is no particular reason why it should, after all. You can easily check that it is orthogonal (CC ^* = I). So it takes 8 time-slots to transmit 4 symbols, and is a rate-1/2 STBC. (Also, check the cited paper, [6]). 137.222.189.198 16:05, 19 February 2007 (UTC)