Forums

OFDM(doppler shift estimation)

Started by .avinash. August 31, 2015
Hey there everyone!
I'm actually right now researching about ofdm based realization to
efficiently estimate the doppler shift and I've kinda run into a block
In the typical block diagram there's a IFFT/FFT block,I've read on many
forums but I'm unable to determine the significance of the said block
Also,if its possible could anyone help me understand why actually circular
convolution is better rather than linear convolution
The code that I'm writing to implement the same is in Matlab

Thank you in advance for your help
Avinash.


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Posted through http://www.DSPRelated.com
On Mon, 31 Aug 2015 10:36:02 -0500, ".avinash." <108300@DSPRelated>
wrote:

>Hey there everyone! >I'm actually right now researching about ofdm based realization to >efficiently estimate the doppler shift and I've kinda run into a block >In the typical block diagram there's a IFFT/FFT block,I've read on many >forums but I'm unable to determine the significance of the said block >Also,if its possible could anyone help me understand why actually circular >convolution is better rather than linear convolution >The code that I'm writing to implement the same is in Matlab > >Thank you in advance for your help >Avinash. > > >--------------------------------------- >Posted through http://www.DSPRelated.com
These are pretty fundamental questions best answered first in a good comm textbook or tutorial about the basics of OFDM. This assumes you already know what an FFT is, which is it sounds like you may not. In that case, before looking into the communication-oriented specifics of OFDM, you need to first understand the signal processing associated with the Fourier Transform and the differences between linear and circular convolution and how that applies to operations performed with the FFT. Once you do that it will be easier to understand how OFDM handles channel delay spreads. In short, a newsgroup on the internet is not the best way to learn these things. Eric Jacobsen Anchor Hill Communications http://www.anchorhill.com
eric.jacobsen@ieee.org (Eric Jacobsen) writes:
> [...] > In short, a newsgroup on the internet is not the best way to learn > these things.
+1 -- Randy Yates Digital Signal Labs http://www.digitalsignallabs.com
On Mon, 31 Aug 2015 16:22:22 +0000, Eric Jacobsen wrote:

> On Mon, 31 Aug 2015 10:36:02 -0500, ".avinash." <108300@DSPRelated> > wrote: > >>Hey there everyone! >>I'm actually right now researching about ofdm based realization to >>efficiently estimate the doppler shift and I've kinda run into a block >>In the typical block diagram there's a IFFT/FFT block,I've read on many >>forums but I'm unable to determine the significance of the said block >>Also,if its possible could anyone help me understand why actually >>circular convolution is better rather than linear convolution The code >>that I'm writing to implement the same is in Matlab >> >>Thank you in advance for your help Avinash. >> >> >>--------------------------------------- >>Posted through http://www.DSPRelated.com > > > These are pretty fundamental questions best answered first in a good > comm textbook or tutorial about the basics of OFDM. This assumes you > already know what an FFT is, which is it sounds like you may not. > > In that case, before looking into the communication-oriented specifics > of OFDM, you need to first understand the signal processing associated > with the Fourier Transform and the differences between linear and > circular convolution and how that applies to operations performed with > the FFT. Once you do that it will be easier to understand how OFDM > handles channel delay spreads. > > In short, a newsgroup on the internet is not the best way to learn these > things.
Yup. Book-length answers don't fit well in 500 word posts. -- Tim Wescott Wescott Design Services http://www.wescottdesign.com