4 семестр ИКТ 6 вариант / ЛР3 СПВТ

Лабораторная работа №3

Задание 1

1. N=6

Ndigits = 5000;

Py1x2 = 0.06;

Py2x1 = 0.06;

j = 0;

for p = 0:0.1:1

j = j + 1;

res = 0;

res = bsc_new(Ndigits, p, Py1x2, Py2x1, 0);

ProbPy1(j) = res(1);

ProbPy2(j) = res(2);

ProbSum(j) = res(1) + res(2);

ProbError(j) = res(3);

Axis(j) = p;

end

plot(Axis,ProbError, '-ro', Axis, ProbPy1, '-bx', Axis, ProbPy2, '-ms', Axis, ProbSum, '-g+');

xlabel('Probability Px1');

legend('Pe', 'Py1', 'Py2','Py1+Py2');

function [res] = bsc_new(Ndigits, Px1, Py1x2, Py2x1, option)

y1 = 0;

y2 = 0;

CountError = 0;

for i = 1:Ndigits

TransBit = BinarySource(Px1);

RecBit = Channel(TransBit, Py2x1, Py1x2);

if (RecBit == 0)

y1 = y1 + 1;

else

y2 = y2 + 1;

end

if ( RecBit ~= TransBit)

CountError = CountError + 1;

end

end

if (option == 1)

disp('----------------------------');

disp('Simultion Results');

disp('----------------------------');

disp('Probability Py1');

disp(y1/Ndigits);

disp('Probability Py2');

disp(y2/Ndigits);

disp('Py1 + Py2');

disp(y1/Ndigits + y2/Ndigits);

disp('Probability of an error in a binary digit');

disp(CountError/Ndigits);

disp('----------------------------');

Px2 = 1 - Px1;

Py2x2 = 1 - Py1x2;

Py1x1 = 1- Py2x1;

disp('Theoretical Results');

disp('----------------------------');

disp('Expected Py1 = ');

Py1 = Py1x1*Px1 + Py1x2*Px2;

disp(Py1);

disp('Expected Py2 = ');

Py2 = Py2x1*Px1 + Py2x2*Px2;

disp(Py2);

disp('Expected Pe = ');

Pe =Py1x2*Px2 + Py2x1*Px1;

disp(Pe);

disp('----------------------------');

end

res(1) = y1/Ndigits;

res(2) = y2/Ndigits;

res(3) = res(1)+res(2);

res(4) = CountError/Ndigits;

disp(res)

Задание 2

for alpha = 0.1:0.1:0.5

j = j + 1;

PeSim3(j) = DCS(100, 0.5, alpha, 3);

PeSim6(j) = DCS(100, 0.05, alpha, 6);

Theory3(j) = PeTheory(3, alpha);

Theory6(j) = PeTheory2(6, alpha);

Axis(j) = alpha;

end

function pe = PeTheory2(n, alpha)

sum = 0;

for i = (n/2) + 1 : 1 : n

tmp1 = factorial(n);

tmp2 = factorial(n-i);

tmp3 = factorial(i);

tmp4 = alpha^i;

tmp5 = (1-alpha)^(n-i);

sum = sum + (tmp1/(tmp2*tmp3))*tmp4*tmp5;

end

pe = sum;