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Regarding channel estimation in OFDM with pilots.

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kelvin_sg

channel estimation in ofdm

OFDM systems, one only need to take out the received pilots, divide
with known pilots and interpolate the samples between pilots, then
divide the chips with these interpolated samples. Is my understanding
correct?

How do I interpolate these complex pilots? Can they be done with simple
lagrange interpolators :?:

check ur performance.

there are a number of interpolation methods used in OFDM, namely linear,2nd-order gaussian , lowpass and spline cubic interpolation.
the applied method in each OFDM system depends on system requirments.

samuraign said:
check ur performance.

Regarding interpolation, do I treat the I and Q data independently with same
as if we do with simple curve fitting?

Or do I interpolate in polar coordinate, meaning amplitude and phase?

TIA

u can do independently

Re: channel estimation in ofdm

OFDM systems, one only need to take out the received pilots, divide
with known pilots and interpolate the samples between pilots, then
divide the chips with these interpolated samples. Is my understanding
correct?

How do I interpolate these complex pilots? Can they be done with simple
lagrange interpolators :?:

Plz tell me how these pilots are added at transmitter side.
Also help me by tellin how it is done in matlab

Re: channel estimation in ofdm

Hi,
check out the following book.
MIMO-OFDM WIRELESS COMMUNICATIONS WITH MATLAB by Yong Soo Cho, Jaekwon Kim, Won Young Yang, Chung G. Kang.

It has some matlab code that shows how to insert pilot symbols and do channel estimation using LMS and MSE and channel equalization. You can get the book off the Internet. The examples codes use linear interpolation to estimate the frquency response of the channel.

Good luck.

I have found that polar coordinates interpolation works better, in general. This is fine for MATLAB simulations, but in practice, it will be more complexity since you'll have to use the CORDIC algorithm for fixed-point, real-time implementation.

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