function y = demodulate(x, b, e, h, s2,s4,s16,s64,s256, c2,c4,c16,c64,c256);% function y = demodulate(x, b, e, s2,s4,s16,s64,s256, c2,c4,c16,c64,c256);%% Finds minimum distance estimate of each received signal and returns the% corresponding binary codeword.  Use a Zero-Forcing approach for convenience%%    y - modulated output, in the form of a row vector%    x - a vector of input symbols, for all the subcarriers (row vector)%    h - channel value (in frequency) for all subcarriers (64 elements)%    b - subcarrier bit allocation (64 elements in this matrix, each one%        corresponding to the number of bits to be allocated to the subcarrier%        having the same index)%    e - energy allocation (64 elements in this matrix)%    s_ - the encoder for a given constellation size%    c_ - the codewords as vectors of bits for the indicesy=[];for i = 1:length(b)    switch b(i)    case {1}        [tmp, index] = min(abs(s2-1/h(i)/sqrt(e(i))*x(i)));        y = [y c2(index,:)];    case {2}        [tmp, index] = min(abs(s4-1/h(i)/sqrt(e(i))*x(i)));        y = [y c4(index,:)];    case {4}        [tmp, index] = min(abs(s16-1/h(i)/sqrt(e(i))*x(i)));        y = [y c16(index,:)];    case {6}        [tmp, index] = min(abs(s64-1/h(i)/sqrt(e(i))*x(i)));        y = [y c64(index,:)];   case {8}        [tmp, index] = min(abs(s256-1/h(i)/sqrt(e(i))*x(i)));        y = [y c256(index,:)];   otherwise        index = 0;   endend