Added scrambler sequence script

This is from https://www.sharetechnote.com/html/Handbook_LTE_PseudoRandomSequence.html

matlab/generate_scrambler_seq.m

@@ -0,0 +1,45 @@
+function [bits] = generate_scrambler_seq(num_bits, x2_init)
+    % https://www.sharetechnote.com/html/Handbook_LTE_PseudoRandomSequence.html
+    % https://edadocs.software.keysight.com/pages/viewpage.action?pageId=6076479
+    % Initial condition of the polynomia x1(). This is fixed value as described in 36.211 7.2
+    x1_init = [1 0 0 0 0 0 0 0 0 0 ...
+               0 0 0 0 0 0 0 0 0 0 ...
+               0 0 0 0 0 0 0 0 0 0 ...
+               0];
+   
+    
+    % Mpn is the length of the final sequence c()
+    Mpn = num_bits;
+    
+    % Nc as defined in 36.211 7.2
+    Nc = 1600;
+    
+    % Create a vector(array) for x1() and x2() all initialized with 0
+    x1 = zeros(1,Nc + Mpn + 31);
+    x2 = zeros(1,Nc + Mpn + 31);
+    
+    % Create a vector(array) for c() all initialized with 0
+    c = zeros(1,Mpn);
+    
+    % Initialize x1() and x2()
+    x1(1:31) = x1_init;
+    x2(1:31) = x2_init;
+    
+    % generate the m-sequence : x1()
+    for n = 1 : (Mpn+Nc)
+       x1(n+31) = mod(x1(n+3) + x1(n), 2);
+    end
+    
+    
+    % generate the m-sequence : x2()
+    for n = 1 : (Mpn+Nc)
+       x2(n+31) = mod(x2(n+3) + x2(n+2) + x2(n+1) + x2(n),2);
+    end
+    
+    % generate the resulting sequence (Gold Sequence) : c()
+    for n = 1 : Mpn
+        c(n)= mod(x1(n+Nc) + x2(n+Nc),2);
+    end
+    
+    bits = c;
+end