mqam_project_7.m

64QAM matlab s programs.

%---------------------------------------%
% Define Discrete Simulation Parameters %
%---------------------------------------%

num_pulses = 1000; % number of pulses to simulate
num_bits = num_pulses*4; % number of bits to transmit (4-ary)
num_samples_pulse = 99; % number of samples for pulse duration (note 4 bits/pulse)
pulse_rate=100; % pulses/s
pulse_period = 1/pulse_rate; % Time between pulses
sample_rate = pulse_rate*num_samples_pulse  % simulation samples/sec
sample_period = 1/sample_rate; % time for each simulation sample
total_time = num_pulses * pulse_period % total simulation time

% Set up time sample array for simulation
t = [0:sample_period:total_time-sample_period];

%----------------------%
% Generate binary data %
%----------------------%

% generate binary "message"
rand('seed',1)
bit_stream = rand(1,num_bits) > .5;

% conver the binary stream into a_i and b_i values
[a,b]=QAM_bits2ab(bit_stream);

plot(a,b,'r*')
xlabel('a_i')
ylabel('b_i')
title('Transmitter Modulation Constellation')
grid
% Transmitter Modulation transition diagram

%-------------------------------%
% Create Delta Function Signals %
%-------------------------------%

% generate delta function versions of a and b
start_sample_indices = [ (num_samples_pulse+1)/2 : num_samples_pulse : length(a)*num_samples_pulse ];

a_delta = zeros(1,length(a)*num_samples_pulse);
a_delta(start_sample_indices) = a;

b_delta = zeros(1,length(b)*num_samples_pulse);
b_delta(start_sample_indices) = b;

% plot a small portion of the delata data signals
plot(t,a_delta,'r-',t,b_delta,'b-')
xlabel('t (seconds)');
ylabel('Amplitude (Volts)')
title('a_i and b_i as narrow polar pulses (almost delta functions)');
axis([.3,.5,-2,2]);
legend('a_i','b_i')

%-------------------------%
% Generate pulse waveform %
%-------------------------%

% Generate single raised cosine pulse

%---------------------%
% Perform line coding %
%---------------------%

% Form transmitted signal
% convolve delta signals with pulse
% perform carrier modulation


%------------------%
% Simulate Channel %
%------------------%

% Form received signal
% Channel BPF and noise


%--------------%
% Demodulation %
%--------------%

% Get m1 and m2 signals

%-------------------%
% Decode Bit Stream %
%-------------------%

% Convert back to bit stream
bits_out=QAM_ab2bits(m1(start_sample_indices),m2(start_sample_indices));

% Compare with input bit stream to find bit errors
pe = bit_error_probability(bit_stream,bits_out)