'Corrected'... like the lab wants it

lab_1/lab_1.asv

@@ -1,89 +0,0 @@
-% generating error patterns using gilbert-elliot model
-
-p_gg = 0.99;
-p_bb = 0.1;
-p_bg = 1 - p_bb;
-
-% freely chosen bit error probability
-e_g = 10^-4;
-e_b = 10^-1;
-
-% generate random bitstream
-bits_array_len = 10^6;
-bits = randi([0, 1], 1, bits_array_len);
-
-% start with a clean error free pipe
-channel_state = true;
-
-% preallocated array/vector for the resulting bits
-result_stream = zeros(1, bits_array_len);
-
-bit_error_rate_counter = 0;
-gap_begin = 1; % stores the last dirty bit idx, meaning the begin of a new gap
-gap_tracker = []; % holds a 3xn matrix of begin and end gap values and the gap size between them
-
-state_sequence = []; % collector array for the visited states
-
-for it = 1 : bits_array_len
-    current_bit = bits(it);
-
-    % two different rands for channel and bit logic
-    % to prevent unwanted coupling of these two mechanics
-    channel_change_probability = rand();
-    bit_error_probability = rand();
-
-    % error and channel
-    if channel_state == true
-        state_sequence(end + 1) = 'Good';
-        % channel selection from good state with probability p_gg
-        if channel_change_probability < p_gg
-            channel_state = 1;
-        else
-            channel_state = 0;
-        end
-        
-        % flip the bit with probability e_g
-        if bit_error_probability < e_g
-            received_bit = 1 - current_bit;
-        else 
-            received_bit = current_bit;
-        end
-    else
-        % change channel to good with probability of p_bg
-        if channel_change_probability < p_bg
-            channel_state = 1;
-        else
-            channel_state = 0;
-        end
-
-        if bit_error_probability < e_b
-            received_bit = 1 - current_bit;
-        else 
-            received_bit = current_bit;
-        end
-    end
-
-    result_stream(it) = received_bit;
-
-    % BER and Gap
-    if current_bit ~= received_bit
-        bit_error_rate_counter = bit_error_rate_counter + 1;
-        
-        gap_tracker(:, end + 1) = [gap_begin; it; it - gap_begin - 1];
-        gap_begin = it;
-    end
-end
-
-gap_tracker(:, 1) = []; % trim first gap, this is a fault entry by design
-bit_error_rate = bit_error_rate_counter / bits_array_len
-
-gap_sizes = gap_tracker(3, :);
-gap_sizes = gap_sizes(gap_sizes <= 500); % limit gap size to 500 for histogram
-
-histogram(gap_sizes, 'BinEdges', -0.5:1:500.5);
-xlabel('Gap size')
-ylabel('Frequency')
-title('Histogram of gap sizes between consecutive errors')
-
-% for pdf, 1 - 2 sites, describe what i did and what the results were and
-% are

lab_1/lab_1.m

@@ -4,9 +4,8 @@ p_gg = 0.99;
 p_bb = 0.1;
 p_bg = 1 - p_bb;
 
-% freely chosen bit error probability
+e_g = 1 - p_gg;
-e_g = 10^-4;
+e_b = p_bb;
-e_b = 10^-1;
 
 % generate random bitstream
 bits_array_len = 10^6;
@@ -32,10 +31,17 @@ for it = 1 : bits_array_len
     % two different rands for channel and bit logic
     % to prevent unwanted coupling of these two mechanics
     channel_change_probability = rand();
-    bit_error_probability = rand();
+    bit_error_probability = channel_change_probability; % rand();
 
     % error and channel
     if channel_state == true
+        % flip the bit with probability e_g
+        if bit_error_probability >= p_gg
+            received_bit = 1 - current_bit;
+        else 
+            received_bit = current_bit;
+        end
+        
         % channel selection from good state with probability p_gg
         if channel_change_probability < p_gg
             channel_state = 1;
@@ -44,14 +50,13 @@ for it = 1 : bits_array_len
             state_sequence(end + 1) = string(state_visit_counter) + 'x Good';
             state_visit_counter = 0;
         end
-        
+    else
-        % flip the bit with probability e_g
+        if bit_error_probability >= p_bg
-        if bit_error_probability < e_g
             received_bit = 1 - current_bit;
         else 
             received_bit = current_bit;
         end
-    else
+        
         % change channel to good with probability of p_bg
         if channel_change_probability < p_bg
             channel_state = 1;
@@ -60,12 +65,6 @@ for it = 1 : bits_array_len
         else
             channel_state = 0;
         end
-
-        if bit_error_probability < e_b
-            received_bit = 1 - current_bit;
-        else 
-            received_bit = current_bit;
-        end
     end
 
     result_stream(it) = received_bit;
@@ -85,7 +84,7 @@ bit_error_rate = bit_error_rate_counter / bits_array_len;
 gap_sizes = gap_tracker(3, :);
 gap_sizes = gap_sizes(gap_sizes <= 500); % limit gap size to 500 for histogram
 
-histogram(gap_sizes, 'BinEdges', -0.5:1:500.5);
+histogram(gap_sizes, 'BinWidth', 10);
 xlabel('Gap size')
 ylabel('Frequency')
 title('Histogram of gap sizes between consecutive errors')