Initial push

2026-04-23 21:34:07 +02:00
commit 7c91ba9129
3 changed files with 184 additions and 0 deletions
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+% 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_size_tracker = [];
+current_gap_size = 0;
+
+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
+        % channel selection from good state with probability p_gg
+        if channel_change_probability < p_gg
+            channel_state = 1;
+        else
+            channel_state = 0;
+        end
+        
+        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_size_tracker(end + 1) = current_gap_size;
+        current_gap_size = 0;
+    end
+
+    current_gap_size = current_gap_size + 1;
+end
+
+bit_error_rate = bit_error_rate_counter / bits_array_len
+
+% limit gap size to 500 in histogram
+% for pdf, 1 - 2 sites, describe what i did and what the results were and
+% are