Re: [Discuss-gnuradio] Why the Qam modulation cannot work well in ofdm benchmark example?

On Sun, Nov 3, 2013 at 5:09 AM, Martin Braun (CEL) <martin.braun@kit.edu> wrote:

On Fri, Nov 01, 2013 at 07:23:33PM -0700, Yingjie Chen wrote:
> Recently, I have conducted a project based on ofdm benchmark. However, when I
> use the high modulation rate like qam16 and qam64, the packet error rate
> increase significantly. I guess the reason is that the preamble in gunradio is
> too weak to do channel estimation, thereby raising the  packet error rate. 
>
> Furthermore, even though I test the example offline without going through the
> channel, the packet error rate  still very high, which make me feel confused.
> It is supposed to perform normally offline, without any decoding error right?

In order to do QAM over OFDM, you will need a good equalizer; we
currently don't have good ones implemented.

MB

Thanks for the clarification. I've been grappling with the high packet error rates for a while now. :)

Aditya