c9_mcbfsk.m

《通信系统仿真原理与无线应用》的matlab

% File: c9_MCBFSK.m
% Software given here is to accompany the textbook: W.H. Tranter, 
% K.S. Shanmugan, T.S. Rappaport, and K.S. Kosbar, Principles of 
% Communication Systems Simulation with Wireless Applications, 
% Prentice Hall PTR, 2004.
%
clear all
snrdB_min = 0; snrdB_max = 10;			% SNR (in dB)limits
snrdB = snrdB_min:1:snrdB_max;
Nsymbols = input('Enter number of symbols > ');
snr = 10.^(snrdB/10);					% convert from dB
h = waitbar(0,'SNR Iteration');
len_snr = length(snrdB);
for j=1:len_snr						    % increment SNR
   waitbar(j/len_snr)
   sigma = sqrt(1/(2*snr(j)));	        % noise standard deviation
   error_count = 0;
   for k=1:Nsymbols					    % simulation loop begins
      d = round(rand(1));			    % data
      if d ==0
         x_d = 1;						% direct transmitter output	
         x_q = 0;						% quadrature transmitter output	
      else
         x_d = 0;						% direct transmitter output
         x_q = 1;						% quadrature transmitter output
      end   
      n_d = sigma*randn(1);		        % direct noise component
      n_q = sigma*randn(1);		        % quadrature noise component
      y_d = x_d + n_d;				    % direct receiver input
      y_q = x_q + n_q;				    % quadrature receiver input
      if y_d > y_q					    % test condition						
         d_est = 0;					    % conditional data estimate
      else
         d_est = 1;					    % conditional data estimate
      end
      if (d_est ~= d)				
         error_count = error_count + 1;	% error counter
      end
   end									% simulation loop ends
   errors(j) = error_count;		        % store error count for plot
end
close(h)
ber_sim = errors/Nsymbols;			    % BER estimate
ber_theor = q(sqrt(snr));			    % theoretical BER
semilogy(snrdB,ber_theor,snrdB,ber_sim,'o')
axis([snrdB_min snrdB_max 0.0001 1])
xlabel('SNR in dB')
ylabel('BER')
legend('Theoretical','Simulation')
% End of script file.