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Why the IFFT length in LTE is not in the power of 2 for bandwidth of 3MHZ &15 MHz

+3 votes
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for 3MHZ it is 320 which is not the power of 2 and for 15 its 1536 again which is not the power of 2

posted Jan 19, 2014 by anonymous

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1 Answer

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>> IFFT size/length means number of sine waves the IFFT takes as input to construct the time domain signal. In case of 20 MHz the IFFT size is 2048 that means 2048 sub-carriers are used to construct the time domain signal. (Note: not all are occcupied).

IFFT Table

the IFFT size is "IDFT(Tx)/DFT(Rx) size" in the table provided above.

So for 3 Mhz it is 256 not 320.

for 2nd Query -

IFFT in LTE

IFFT-2

IFFT-3

For clear description please click here

answer Feb 25, 2014 by Hiteshwar Thakur
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