recurse_other.m

Hierarchical－QAM的程序

function [err_value] = recurse_other(position, theta_input_vector, snr)

% This function recursively finds out the ber of bits in positions i_{1} 
% to i_{n-1}

n=length(theta_input_vector);
if(n>1)
    theta_output_vector1=zeros(n-1,1);
    theta_output_vector2=zeros(n-1,1);
end;

if(n>1)
    if( position<n+1)
	  alpha=theta_input_vector(n-1)+theta_input_vector(n);
	  beta=theta_input_vector(n-1)-theta_input_vector(n);

        if (n > 2)
    		for i=1:n-2
                theta_output_vector1(i,1)=theta_input_vector(i);
		        theta_output_vector2(i,1)=theta_input_vector(i);
  		    end;
        end;
     		theta_output_vector1(n-1,1)=alpha;
       		theta_output_vector2(n-1,1)=beta;
    theta_output_vector1;
    theta_output_vector2;
    position;
    snr;
    
	    err_value=0.5*recurse_other(position, theta_output_vector1, snr)+0.5*recurse_other(position, theta_output_vector2, snr);
    else
        err_value=lsb_error_new(theta_input_vector, 1/(snr*snr));
    end;
elseif( n==1 )
        if(position == 1)
	        err_value = 0.5*erfc(sin(theta_input_vector(1))/snr);
        elseif(position == 2)
            err_value= 0.5*erfc(cos(theta_input_vector(1))/snr);
        end;  
    end;