berg_cmegd.m

有关信道估计和信道均衡的仿真程序

% this handles the exact-gradient-descent CMA algorithms for the
% bergulator, and is called by ui_traj.m
%
% if not available for your platform, you can create a .mex version 
% by typing "mex -O berg_cmegd.c" at the system prompt
 
% Copyright 1997-1998 Phil Schniter

function [f,y,srcme] = berg_cmegd(N,N_f,D_f,D_e,is_FSE,kappa,mu,r,f_init,alg,sigma2_n,C);

 f_cur = f_init;
 f = zeros(N_f,floor((N-1)/D_f)+1);    	% equalizer history
 y = zeros(1,floor((N-1)/D_e)+1);      	% soft decisions
 srcme = zeros(1,floor((N-1)/D_e)+1);  	% sqrt(CM) error history
 if alg==0,                		% PAM source with real noise
   for i = 1:N,
     reg = r(1, N_f+(1+is_FSE)*i:-1:(1+is_FSE)*i+1);
     y_cur = reg*f_cur;      		% for constellation plot...
     h = C*f_cur;
     hTh = norm(h)^2;
     fTf = norm(f_cur)^2;
     srcme_cur = sqrt( kappa^2 - 2*kappa*(hTh + sigma2_n*fTf)...
        + 3*hTh^2 + (kappa-3)*norm(h.^2).^2 ...
        + 6*sigma2_n*hTh*fTf + 3*sigma2_n^2*fTf^2 );
     dJdf = (kappa-3)*C'*(h.^3) + (3*hTh + 3*sigma2_n*fTf - kappa)*...
        (C'*h + sigma2_n*f_cur);
     f_cur = f_cur  - mu*dJdf;
     f(:,floor((i-1)/D_f)+1) = f_cur;
     y(floor((i-1)/D_e)+1) = y_cur;
     srcme(floor((i-1)/D_e)+1) = srcme_cur;
   end
 elseif alg==1,                 	% PAM source with rot.inv. noise
   for i = 1:N,
     reg = r(1, N_f+(1+is_FSE)*i:-1:(1+is_FSE)*i+1);
     y_cur = reg*f_cur;      % for constellation plot...
     h = C*f_cur;
     hTh = norm(h)^2;
     fTf = norm(f_cur)^2;
     srcme_cur = sqrt( (kappa-3)*sum(abs(h).^4) + 2*hTh^2 + abs(h.'*h)^2 ...
       + 2*sigma2_n^2*fTf^2 + 4*sigma2_n*hTh*fTf...
       - 2*kappa*(hTh + sigma2_n*fTf) + kappa^2 );
     dJdf = (kappa-3)*C'*(h.*(abs(h).^2)) + (h.'*h)*C'*conj(h)...
       + (2*hTh + 2*sigma2_n*fTf - kappa)*(C'*h + sigma2_n*f_cur);
     f_cur = f_cur - mu*dJdf;
     f(:,floor((i-1)/D_f)+1) = f_cur;
     y(floor((i-1)/D_e)+1) = y_cur;
     srcme(floor((i-1)/D_e)+1) = srcme_cur;
   end
 elseif alg==2,                          % QAM source with rot.inv. noise
   for i = 1:N,
     reg = r(1, N_f+(1+is_FSE)*i:-1:(1+is_FSE)*i+1);
     y_cur = reg*f_cur;      % for constellation plot...
     h = C*f_cur;
     hTh = norm(h)^2;
     fTf = norm(f_cur)^2;
     srcme_cur = sqrt( (kappa-2)*sum(abs(h).^4) + 2*hTh^2 ...
       + 2*sigma2_n^2*fTf^2 + 4*sigma2_n*hTh*fTf...
       - 2*kappa*(hTh + sigma2_n*fTf) + kappa^2 );
     dJdf = (kappa-2)*C'*(h.*(abs(h).^2))...
       + (2*hTh + 2*sigma2_n*fTf - kappa)*(C'*h + sigma2_n*f_cur);
     f_cur = f_cur - mu*dJdf;
     f(:,floor((i-1)/D_f)+1) = f_cur;
     y(floor((i-1)/D_e)+1) = y_cur;
     srcme(floor((i-1)/D_e)+1) = srcme_cur;
   end
 else
   error('That algorithm is not supported by berg_cmegd.m');
 end;