Re: [Discuss-gnuradio] In ofdm example, is channel estimation work only done in one preamble per frame or each symbol per frame?

[Tom Rondeau]

On Fri, Apr 5, 2013 at 6:23 AM, Yingjie Chen <address@hidden> wrote:
> Hi guy,
>
> I am currently working on ofdm example. I try to print out the channel
> estimated value d_hestimate on terminal. However, I found each frame number
> followed several sets of channel estimated value. I feel so confused because
> I believe channel estimation is only done in preamble for each frame. It
> should be only one set of channel estimated value following one frame, is
> that right?

Yes, that's right, the hestimate should only be calculated on the
preamble. Are you doing this over the air or under simulation? I would
suggest starting in simulation to make sure that there are no outside
effects happening that causing the receiver to trigger the
re-estimation.

Are you using the VERBOSE output of the file? Just set VERBOSE to 1 at
the top of the ofdm_frame_acquisition file and it will print out its
values for you. I know we debugged using this and the estimations
looked fine. We were able to plot the channel this way, and it looked
pretty good.

Tom