qpsk in rayleigh channel simulation changes everytime you simulate

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sharvari samant 2013-9-30

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https://ww2.mathworks.cn/matlabcentral/answers/88681-qpsk-in-rayleigh-channel-simulation-changes-everytime-you-simulate

评论： sharvari samant 2013-9-30

plot of ber vs enno for qpsk in rayleigh channel using the object rayleighchan changes for each simulation.why is this happening?my code is as follows: % Create Rayleigh fading channel object. chan = rayleighchan(1/10000,0);

% Generate data and apply fading channel. M = 4; % QPSK modulation order hMod = modem.pskmod('M', M,'InputType','bit'); % Create a QPSK modulator hDemod =modem.pskdemod('M',M,'OutputType','bit','DecisionType','hard decision'); % Create a QPSK demodulator % using the modulator tx = randsrc(50000,1,[0 1]); % Generate a random bit stream dpskSig = modulate(hMod, tx); % QPSK modulate the signal fadedSig = filter(chan,dpskSig); % Apply the channel effects

% Compute error rate for different values of SNR. SNR = 0:2:40; % Range of SNR values, in dB. numSNR = length(SNR); BER = zeros(1, numSNR); for n = 1:numSNR rxSig = awgn(fadedSig,SNR(n)); % Add Gaussian noise rx = demodulate(hDemod, rxSig); % Demodulate % Compute error rate. [nErrors, BER(n)] = biterr(tx,rx); end

% Plot BER results. semilogy(SNR,BER,'r*'); legend('Empirical BER'); xlabel('SNR (dB)'); ylabel('BER'); title('Binary QPSK over Rayleigh Fading Channel');

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sharvari samant 2013-9-30

编辑：sharvari samant 2013-9-30

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plot of ber vs enno for qpsk in rayleigh channel using the object rayleighchan changes for each simulation.why is this happening?my code is as follows:

% Create Rayleigh fading channel object.

chan = rayleighchan(1/10000,0);

% Generate data and apply fading channel.

M = 4; % QPSK modulation order

hMod = modem.pskmod('M', M,'InputType','bit'); % Create a QPSK modulator

hDemod =modem.pskdemod('M',M,'OutputType','bit','DecisionType','hard decision'); % Create a QPSK demodulator

tx = randsrc(50000,1,[0 1]); % Generate a random bit stream

dpskSig = modulate(hMod, tx); % QPSK modulate the signal

fadedSig = filter(chan,dpskSig); % Apply the channel effects

% Compute error rate for different values of SNR.

SNR = 0:2:40; % Range of SNR values, in dB.

numSNR = length(SNR);

BER = zeros(1, numSNR);

for n = 1:numSNR

   rxSig = awgn(fadedSig,SNR(n));   % Add Gaussian noise
   rx = demodulate(hDemod, rxSig);  % Demodulate
   % Compute error rate.
   [nErrors, BER(n)] = biterr(tx,rx);

end

% Compute theoretical performance results, for comparison.

% Plot BER results.

semilogy(SNR,BER,'r*');

legend('Empirical BER');

xlabel('SNR (dB)'); ylabel('BER');

title('Binary QPSK over Rayleigh Fading Channel');

sharvari samant 2013-9-30