Welcome to EDAboard.com

Welcome to our site! EDAboard.com is an international Electronics Discussion Forum focused on EDA software, circuits, schematics, books, theory, papers, asic, pld, 8051, DSP, Network, RF, Analog Design, PCB, Service Manuals... and a whole lot more! To participate you need to register. Registration is free. Click here to register now.

16 QAM simulation over Rayleigh channel in Matlab

Status
Not open for further replies.

agent007

Newbie level 4
Joined
Oct 9, 2011
Messages
5
Helped
0
Reputation
0
Reaction score
0
Trophy points
1,281
Activity points
1,324
Hello everyone! I would like to demodulate 16 QAM modulated signal after Flat Rayleigh Channel and AWGN by usining modem.qamdemod. My BER graph is far from the thoretical. Any help will be appreciated.
Den.

Here is my code:

% Create Rayleigh fading channel object.
chan = rayleighchan;

g = chan.PathGains % Retrieve the PathGains property

dop_flat = doppler.flat
chan.DopplerSpectrum = dop_flat
chan.StorePathGains = 1;
chan.ResetBeforeFiltering=0;
chan

M = 16; % QAM modulation order
k = log2(M);
hMod=comm.RectangularQAMModulator(M); % Create a 16 QAM modulator
display(hMod)

%hDemod=comm.RectangularQAMDemodulator; % Create a 16 QAM Demodulator
%hDemod.outputtype='bit';
%display(hDemod)

% Initialize scatter plot.
scatterPlot = commscope.ScatterPlot;
scatterPlot.Constellation=16;

tx = randint(1e4,1,M); % Generate a random bit streams

qamSig = step(hMod, tx); % Modulate16 QAM the signal


% Compute error rate for different values of EbNo
EBNO = 1:50; % Range of EbNo values, in dB.
numEBNO = length(EBNO);


for n = 1:length(EBNO)

hDemod=comm.RectangularQAMDemodulator; % Create a 16 QAM Demodulator
fadedSig = filter(chan,qamSig); % Apply the channel effects

snr = n + 10*log10(k) - 10*log10(4);
rxSig1= awgn(fadedSig,n,'measured');

eqSig = rxSig1 .* conj(chan.PathGains);

rx = step(hDemod, eqSig); % Demodulate

% Compute error rate.
[nErrors, BER(n)] = biterr(tx,rx);
BER

% Plot the new data
update(scatterPlot,eqSig,'r');

end;

% Compute theoretical performance results, for comparison.
BERtheory =berfading(EBNO,'qam',M,1)

% Plot BER results.
semilogy(EBNO,BERtheory,'b-',EBNO,BER,'r*-');
legend('Theoretical BER','Simulation BER');
xlabel('EbNo (dB)'); ylabel('BER');
title('16 QAM over Rayleigh Channel');
grid on;

end
 

Status
Not open for further replies.

Similar threads

Part and Inventory Search

Welcome to EDABoard.com

Sponsor

Top