Golay complementary sequences for channel estimation - MATLAB
I would try with this code:

channel =[1 0.2]';
Ga=[+1, +1, +1, -1, +1, +1, -1, +1]';
Gb=[+1, +1, +1, -1, -1, -1, +1, -1]';
y1=conv(channel,Ga);
y2=conv(channel,Gb);
correlation_output1=xcorr(y1,Ga);
correlation_output2=xcorr(y2,Gb);
channel_estimation=correlation_output1+ correlation_output2;
stem(channel_estimation./length(Gb)) 


Best regards,