Hi,
I am trying to understand ofdm demodulation using schmidl and cox paper.
Can anybody explain how a pn sequence on even frequencies and 0 on odd
frequencies help in the estimation of timing and frequency offset.
On Wed, Apr 17, 2013 at 6:30 AM, Karan T. [email protected]
wrote:
Hi,
I am trying to understand ofdm demodulation using schmidl and cox paper.
Can anybody explain how a pn sequence on even frequencies and 0 on odd
frequencies help in the estimation of timing and frequency offset.
Hi Karan,
I haven’t read the paper, but here is what I know from the description
of
the scenario. Someone who has more OFDM experience can probably speak
with
a little more authority.
If you skip every other bin in the frequency domain, the time domain
signal
is actually repeated during the whole OFDM symbol. Since the time domain
information is repeated, you can perform a correlation with a delayed
version of the symbol coming in for some rough synchronization of the
preamble. Also, the phase difference of that result will be the average
frequency offset over that number of samples, giving you a decent
frequency
offset estimate as well.
At least, that’s what I think would be useful.
Does that make sense to you?
Brian