I've already use the Fractionally_Spaced-Equalizer at the receiver. I'm
trying to send the coefficient of this equalizer to the transmitter to
have a echo free signals at the receiver. I can get the good result when I
use the symbol spaced equalizer but when I use FSE after upsampler and
before pulse shaping filter at the transmitter I can't get the good
result. I just convolve the upsampled QPSK signal with the coefficients of
the FSE (pre_equalizer) and then pass it to the Pulse shaper (root raised
cosine filter) and transmit it to the channel with ISI and use matched
filter and down sampler at the receiver.
do you know why the FSE can't work well at the pre_equalizer?