comparison.zip_isi_zip

%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% % EVALUATION OF ERROR PROBABILITY UNDER ISI AND AWGN %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% % The overall impulse response of the channel is modeled by chebyshev pulse % Binary modulation is considered % 1000 interference terms are assumed to be nonzero, others have negligible % ampliture A1 = 0.4032; %paramters of the chebyshev pulse A2 = 0.7163; w1 = 2.839; w2 = 1.176; phi1 = 0.7553; phi2 = 0.1602; bet1 = 0.4587; bet2 = 1.107; t = -10:0.01:10; h=(A1*cos((w1*abs(t)/0.5)-phi1).*exp(-bet1*abs(t)/0.5))+... (A2*cos((w2*abs(t)/0.5)-phi2).*exp(-bet2*abs(t)/0.5)); std = 0.2:0.05:1.25; %standard deviation of the AWGN lev = 2; en_d = 1/3*(lev^2-1); en = 0; lam = 0.5; zo = 0.1; p = 1; Pe_wid_isi = []; Pe_widout_isi_psk = []; Pe_widout_isi_fsk = []; va = std.^2; %variance of the noise center = (length(t)-1)/2; snr = h(center)^2./fliplr(va); %vector of SNR snr_db = 10*log(snr); for s = 1.25:-0.05:0.2 %start of algorithm for k = 1:(length(t)-1)/2 f(k) = h(k)/s; end for k = 1:500 en = en+f(k)^2*en_d; p = p*(sinh(2*lam*f(k))/(2*sinh(lam*f(k)))); end Pet = qfunc(f(center)-zo)*exp(0.5*en*lam^2-lam*zo)*p; Pe_wid_isi = [Pe_wid_isi,2*Pet]; end Pe_widout_isi_psk = qfunc(sqrt(2*snr)); Pe_widout_isi_fsk = qfunc(sqrt(snr)); % main code ends here %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% % PLOTTING %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% figure(1) plot(t,h); title('impulse response of the channel'); xlabel('Time'); ylabel('Impulse response'); grid; figure(2) plot(snr_db,Pe_wid_isi,'r'); hold on; plot(snr_db,Pe_widout_isi_psk,'g'); hold on; plot(snr_db,Pe_widout_isi_fsk); title('error probability curves'); xlabel('SNR(dB)'); ylabel('bit error probability'); grid;