Re: [Discuss-gnuradio] the block equalizer in ofdm

[Martin Braun]

On 11.11.2015 01:14, w xd wrote:
>     I have look at the api, and find 4 class about the ofdm equalizer，
> 
>     ofdm_equalizer_1d_pilots,
> ofdm_equalizer_base,ofdm_equalizer_simpledfe,ofdm_equalizer_static.

These are different implementations, and are dropped into the actual
equalizer block (a bit like gr-fec works).

>    1.Can someone tell their difference and relation.

Check out their documentations. They implement different algorithms.

>    2.I look at the ofdm_frame_equalizer_vcvc_impl.cc.
> 
>    and the code
>  
>   "     d_eq->reset();
>       d_eq->equalize(out, frame_len, d_channel_state);
>       d_eq->get_channel_state(d_channel_state);
>     
>   "
>   I know the ofdm grc example use the ofdm_equalizer_simpledfe.Can
> someone tell me the reason of  ofdm_equalizer_simpledfe?It's base on LS
> or MMSE or others?Can someone give a reference about the
>  ofdm_equalizer_simpledfe.

It's based on a zero-forcing approach, but it updates channel estimates
while equalizing (hence dfe == decision-feedback equalizer).

M