Can you help me on this code to identify Eb_N0_dB ? I would like to know also what ipHat is.

The code is as below:

% Script for simulating binary phase shift keyed transmission and % reception and compare the simulated and theoretical bit error % probability clc;clear;close all

N = 10^8 % number of bits or symbols

rand('state',100); % initializing the rand() function

randn('state',200); % initializing the randn() function

% Transmitter

ip = rand(1,N)>0.5; % generating 0,1 with equal probability

s = 2*ip-1; % BPSK modulation 0 -> -1; 1 -> 1

n = 1/sqrt(2)*[randn(1,N) + j*randn(1,N)]; % white gaussian noise, 0dB variance

Eb_N0_dB = [-3:10]; % multiple Eb/N0 values

for ii = 1:length(Eb_N0_dB)

   % Noise addition

   y = s + 10^(-Eb_N0_dB(ii)/20)*n; % additive white gaussian noise

   % receiver - hard decision decoding

   ipHat = real(y)>0;

   % counting the errors

   nErr(ii) = size(find([ip- ipHat]),2);

end

simBer = nErr/N; % simulated ber

theoryBer = 0.5*erfc(sqrt(10.^(Eb_N0_dB/10))); % theoretical ber

% plot

close all

figure

semilogy(Eb_N0_dB,theoryBer,'b.');

hold on

%semilogy(Eb_N0_dB,simBer,'mx-');

 grid on

legend('theory', 'simulation');

xlabel('SNR dB');

ylabel('BER Bit Error Rate');

title('Bit error probability curve for BPSK modulation');

Answer 1

[Image Analyst]

You can find "Eb_N0_dB" on this line. Use the control-F command if you don't see it.

Eb_N0_dB = [-3:10]; % multiple Eb/N0 values

ipHat is defined here:

ipHat = real(y)>0;

It is a boolean/logical variable that is "true" if y has a positive real component.

Granted, the comments in this code are horrible (because there are not enough of them), and you should scold the original author for their bad programming habits.

[Altin Guberi]

So, can Eb_N0_dB be SNR ( Signal To Noise Ratio ) ??

[Walter Roberson]

That is what xlabel() claims the variable represents