# Channel estimation and interpolation by vector in OFDM

I have V-OFDM system (Vector OFDM) where every symbol is organized as in below figure:

The black cirles are pilots and white circles are data. First, iFFT operation it taken per column, and then collecting data is taken row-wise resulting collected data as shown in the figure right. It means first eight samples are pilot and following 24 sample are data, then 8 samples are pilot and so on. Then adding CP --> channel --> noise -->received data

In the receiver side, After usual processing of removing CP -->reshaping --> FFT column wise. We get the received data equivalent into transmitted data in above figure left. Then extract the pilots which are in our case of size $$(3,8)$$.

Then, LS estimation is performed, by dividing the received pilot by original pilot to get the frequency-domain estimated channel.

I ask here, how can we interpolate the channel in this case ? if I get a frequency-domain estimated channel of size $$(3,8)$$, what's the process to interpolate it into size of my symbol ? I think it should be vector interpolation? how can I do it in that case?

Thank you

• Thank you for your feedback. It's OK, but even in my case I can use the interpolation as used in conventional block-type pilot insertion ? for example in conventional OFDM, we use it as y = interp1(1:4:N, h_est, 1:N); where N is the number of subcarriers vector of length N, and h_est the estimated frequency-domain channel which is a vector of length N/4 and y is frequency estimated channel of length N. In my case I have matrix of size $(3,8)$, how can I do the equivalent process ? – Fatima_Ali Mar 31 at 8:09