Both supporting Sum-Product (SPA) and Min-Sum (MSA) Algorithms for LLR caclulations. Corresponding field added on config to select algorithm deployed.

Author: nikos

config.m

@@ -1,6 +1,5 @@
 timestamp = [num2str(start_time(1),'%04d') '_' num2str(start_time(2),'%02d') '_' num2str(start_time(3),'%02d') '_' num2str(start_time(4),'%02d') '_' num2str(start_time(5),'%02d') '_' num2str(start_time(6),'%2.0f')];
 result_path = './results/';
-addpath('support');
 %% Configure parameters
 %Polar-Code values
 capacity = 0.5; %I(W), Channel's W Capacity
@@ -17,6 +16,7 @@
 %seed
 fix_seed = 1;           %1:fix data, 0:random data
 %Simulation values
+decoding_algorithm = 'MSA';     % Set as 'SPA' for Sum-Product algorithm , or 'MSA' for Min-Sum Algorithm.
 fast_run = 1;           %1:run of optimal-matlab code + mex-files, 0:run of hardware-code (suboptimal f/g)
 min_fer_errors = 100;   %minimum frame errors to count
 min_codewords = 100;    %minimum codewords to count
@@ -27,8 +27,11 @@
 FLAG_Enable_parpool=0;    % 0: Disable, 1: Enable
 parcore_nums = 4;
 %% Initializations
-%add mex-files
-if(fast_run == 1)
+%add required matlab paths
+restoredefaultpath;
+addpath('support');
+addpath(['./support/f_function/' decoding_algorithm]);  % for l_f function.
+if(fast_run == 1)   % for mex-files
     addpath('./support/mex_files');
 end
 %initialize seed

support/f.m

@@ -0,0 +1,5 @@
+function y = f(x1,x2)
+%f(?a,?b) proccess
+%Min-Sum Algorithm (MSA) deployed
+y = sign(x1)*sign(x2)*min(abs(x1),abs(x2));
+end

support/f_function/MSA/f.m

@@ -0,0 +1,17 @@
+function output = l_f(l,j,llr,frozen_bits,estimated)
+%Takes l (stage from 1 to log2(N)+1), j-channel (from 1 to N), llr array, frozen
+%bits array and current estimated outputs array
+%outputs the l
+%Min-Sum Algorithm (MSA) deployed
+stages = log2(length(frozen_bits));
+if (l == stages+1)
+    output = llr(j);
+elseif( mod(floor((j-1)/power(2,l-1)),2) == 0)
+    a = l_f(l+1,j,llr,frozen_bits,estimated);
+    b = l_f(l+1,j+power(2,l-1),llr,frozen_bits,estimated);
+    output = sign(a)*sign(b)*min(abs(a),abs(b));
+else
+    output = (1-2*s_f(l,j-power(2,l-1),frozen_bits,estimated)) * (l_f(l+1,j-power(2,l-1),llr,frozen_bits,estimated)) + l_f(l+1,j,llr,frozen_bits,estimated) ;
+end
+
+%correct

support/f_function/MSA/l_f.m

@@ -0,0 +1,5 @@
+function y = f(x1,x2)
+%f(?a,?b) proccess
+%Sum-Product Algorithm (SPA) deployed
+y = 2*atanh(tanh(x1/2)*tanh(x2/2));
+end

support/f_function/SPA/f.m

@@ -2,6 +2,7 @@
 %Takes l (stage from 1 to log2(N)+1), j-channel (from 1 to N), llr array, frozen
 %bits array and current estimated outputs array
 %outputs the l
+%Sum-Product Algorithm (SPA) deployed
 stages = log2(length(frozen_bits));
 if (l == stages+1)
     output = llr(j);