Viterbi generator by Piotr Krysik.

11 files changed, 715 insertions, 0 deletions

diff --git a/viterbi_generator/tests/data/normal_burst.dat b/viterbi_generator/tests/data/normal_burst.dat
new file mode 100644
index 0000000..cbde38a
--- /dev/null
+++ b/viterbi_generator/tests/data/normal_burst.dat
@@ -0,0 +1,6 @@
+# Created by Octave 3.0.0, Sun Dec 07 22:10:44 2008 CET <piotr@piotr-laptop>
+# name: normal_burst
+# type: complex matrix
+# rows: 1
+# columns: 148
+ (7977179.575842334,-2764222.417438231) (6856794.837415899,4865869.971701522) (9811374.762481783,5183732.883723894) (6679440.954922386,-4428971.382695343) (-4696701.829875357,-5933567.044617306) (-6541783.913531991,4653341.980626347) (2084689.136089761,10178136.33389057) (6147479.654568939,8874496.300197551) (5904918.085298464,8800690.925502732) (6748883.359764119,8777701.99895237) (6778221.845496094,8045655.950100697) (6364128.866015259,8022191.027790485) (8722069.281154793,4776436.493770716) (10932320.66341553,-1558217.346711523) (8712591.829617452,-1858753.981212688) (2379782.554878909,2932506.621771185) (-5444416.779109947,5946987.812324719) (-5424576.301366795,8041132.549737221) (4060723.573739645,5559136.64846923) (9867910.71698026,-1816506.536824186) (9116570.97744694,-6509021.212210049) (5005755.561673803,-8815847.513357516) (-2234914.896357608,-10346435.29296497) (-7202255.959453276,-9713796.984525394) (-9190470.490641661,-4700539.204802573) (-10344677.56318331,3164735.076391134) (-8144676.035821493,3689244.844807261) (-2187512.878540438,-2405086.800766177) (4192422.735599967,-2302450.194812776) (7246362.648469473,4298058.743439186) (6556902.896761281,8229181.331930954) (6142925.014497022,8026586.954769152) (8129663.314625547,4033126.426787131) (5840297.475172411,-4620492.674842792) (-1914675.110364774,-10020347.74689682) (-2940115.449563568,-8372239.28186238) (4008522.173926762,-6826920.4027513) (8135500.914007598,-7047328.230427532) (8405763.865765207,-6931698.977370714) (8929684.60841676,-6179537.907816172) (8180060.234703613,-2186703.089556943) (3091335.431867111,4054954.833985379) (-4295697.157828381,7927174.133346504) (-8473978.891786665,8708279.094237776) (-8307511.019450527,8912587.711675741) (-3924398.366246906,9788935.76403868) (3578818.136331406,9475507.775523672) (7878887.060875434,8305521.621609254) (7661073.44413343,8193166.008805315) (7711201.656500887,8476321.863353506) (8106392.393772357,8574168.66012821) (4338938.673600335,8161180.253521944) (-2892764.559653326,7908598.189004728) (-7361426.229118877,8354406.99665704) (-7399748.199851307,9027400.138110537) (-2985443.126902175,10343848.63110767) (4056164.268281491,10098505.09400246) (3662304.483904882,7612823.121273955) (-3973366.81657888,7937078.917571188) (-4235798.145293494,10334281.08680061) (3036808.068953499,9898067.648818504) (7473543.535633441,7807926.377577701) (9079322.039812893,3406424.495665565) (9858644.625831679,-3257437.035834751) (8880394.89067794,-7679278.009140568) (3363837.002219063,-9429173.71625155) (-5976744.033579396,-5385450.603450965) (-9557981.008868802,3050312.808275135) (-7022882.07013285,3640309.418994936) (-6956342.70055424,-3448204.434753519) (-7352343.418384315,-7661573.785117128) (-2991151.171234549,-7200411.918698126) (2885118.044527493,-2984883.7704812) (7032828.106442515,3581754.794175046) (10088763.75405868,3662867.846789958) (10564181.44456883,-3225930.10124573) (8350222.259163288,-3732983.787176989) (7833973.714202324,2987993.691082503) (9706408.673943322,3052094.809291443) (9745006.60948544,-3935102.054010465) (7816404.563798211,-8252538.72673445) (2986277.663389235,-9487975.529977793) (-5695845.629277196,-5169515.812036891) (-10054151.19384441,3411496.45829031) (-8051379.265738308,2941255.219687932) (-3549464.58574895,-3756761.751613705) (2758228.097400823,-3356159.692788773) (3030904.799713606,2423714.179333686) (-4312484.664824991,6565622.532791231) (-8292628.102357071,7907719.341642237) (-7526932.969593002,8014555.798755471) (-7845877.058982445,7739528.888483866) (-8621562.52814143,7418568.373775017) (-8417158.059851743,7181224.216350028) (-8512688.8578708,7987622.681439973) (-4394195.283606119,9949034.472254608) (5266129.291599136,6195329.68568805) (10194253.69504469,-2784736.708811181) (8824963.809236836,-7786593.488088661) (3396738.808078639,-9691138.584095873) (-5722550.505156678,-5556953.717315165) (-5714701.21871692,5472711.90841134) (3332017.262149745,9704527.797128931) (7342514.528813555,7753950.512219134) (6818048.987995462,8189460.303227851) (3394201.964273538,7945062.7654535) (-4167885.511983512,6895554.165900515) (-8619065.547944224,6801211.716255617) (-7427938.633889003,2908143.990531422) (-6703266.997337797,-4149571.893369118) (-7397979.408319066,-8091927.82717395) (-8023643.386183736,-8148580.271161931) (-9593984.742403097,-3401373.756765883) (-9949905.478216713,3693487.850592313) (-7643884.055928037,3256209.472513159) (-2697566.672122434,-3206105.087111734) (3377896.546916216,-3637995.937387224) (7053276.04109713,2764169.146215447) (8628643.160917941,3396969.972018227) (8591483.693362383,-3571890.231694249) (7631932.362041099,-7892583.334526137) (3523270.049984952,-9235294.629945757) (-5210049.188676764,-5470018.026155467) (-5729032.983653861,4597120.705589911) (4722045.647456144,5593554.046296648) (9943005.230296012,-3058974.832172701) (7338276.272285849,-3095524.728011495) (6924101.789435759,4679671.472522281) (9394305.400845038,4311128.98481571) (9835558.718232434,-3667900.007702321) (8223108.712000148,-8579057.297566241) (2845955.65886871,-9157587.991012959) (-5965686.3459505,-4635464.373605222) (-9515672.979250863,3206974.918525696) (-8344649.14188644,7073463.424866714) (-8254731.199008162,7048210.74046527) (-7504645.106599139,3469527.977909835) (-6905884.654448108,-4071500.776307517) (-7265828.021198342,-8724546.709091771) (-3159001.544609685,-7599002.095846066) (4820872.724960422,-7688968.483649141) (4538964.484279973,-10655536.8874595) (-4627802.476316519,-6342339.722614718) (-5229789.984553174,4793436.509895318) (3023641.900808552,9426626.555313969) (3151170.485840399,7510483.156596448) (-3112381.95965953,6480539.799831223) (-3526072.302890599,4305425.630118813)
diff --git a/viterbi_generator/tests/data/rhh.dat b/viterbi_generator/tests/data/rhh.dat
new file mode 100644
index 0000000..4a06772
--- /dev/null
+++ b/viterbi_generator/tests/data/rhh.dat
@@ -0,0 +1,6 @@
+# Created by Octave 3.0.0, Sun Dec 07 22:10:44 2008 CET <piotr@piotr-laptop>
+# name: Rhh
+# type: complex matrix
+# rows: 1
+# columns: 6
+ (6681134.234745174,3.462940897916484e-11) (4315167.063742221,-860367.8252039659) (935284.8973972955,-371780.5098627206) (-51462.68718506447,50393.67553327526) (-7439.804484758702,8028.159897103877) (-0.804484758702,0.159897103877)
diff --git a/viterbi_generator/tests/test_check.m b/viterbi_generator/tests/test_check.m
new file mode 100755
index 0000000..a08c801
--- /dev/null
+++ b/viterbi_generator/tests/test_check.m
@@ -0,0 +1,56 @@
+#!/usr/bin/octave --silent
+addpath("./tests/utils");
+addpath("./utils");
+addpath("./utils/lower_utils");
+addpath("./utils/lower_utils/lower_utils");
+
+arg_list=argv();
+Lh=sscanf(arg_list{1}, "%d", "C");
+PATHS_NUM=2**(Lh);
+load tests/data/rhh.dat;
+load tests/data/normal_burst.dat;
+load test_result;
+
+[r BURST_SIZE] = size(normal_burst);
+
+[ SYMBOLS , PREVIOUS , NEXT , START , STOPS ] = viterbi_init(Lh);
+
+path_metrics_test_result = path_metrics_test_result.';
+[rx_burst METRIC] = viterbi_detector(SYMBOLS,NEXT,PREVIOUS,START,STOPS,normal_burst,Rhh);
+[r,burst_size] = size(METRIC);
+sum_check=0; %number of errors
+
+%find branch metrics computation errors number (errors bigger than 1000)
+for i=1:2:burst_size,
+  check_matrix = (abs(METRIC(1:2:r,i)-path_metrics_test_result(:,i)));
+  suma=sum( check_matrix > ones(PATHS_NUM,1)*1000);
+  sum_check = sum_check + suma;
+  
+  check_matrix = (abs(METRIC(2:2:r,i+1)-path_metrics_test_result(:,i+1)));
+  suma=sum( check_matrix > ones(PATHS_NUM,1)*1000);
+  sum_check = sum_check + suma;
+end
+
+%compute expected number of errors (errors from the beginning)
+q=2;
+expected_result=0;
+while(q<PATHS_NUM),
+  expected_result=expected_result + (PATHS_NUM-q);
+  q=q*2;
+end
+
+%check result
+if(sum_check == expected_result),
+  printf("Path metrics test: ok\n");
+else
+  sum_check
+  printf("Path metrics test: failed\n");  
+end
+
+%check output of the viterbi_detector function
+if(sum(output==rx_burst) == BURST_SIZE),
+  printf("Final result test: ok\n");
+else
+  printf("Final result test: failed\n");  
+end
+
diff --git a/viterbi_generator/tests/test_gen.m b/viterbi_generator/tests/test_gen.m
new file mode 100755
index 0000000..a2639fb
--- /dev/null
+++ b/viterbi_generator/tests/test_gen.m
@@ -0,0 +1,83 @@
+#!/usr/bin/octave --silent
+
+addpath("./tests/utils");
+addpath("./utils");
+addpath("./utils/lower_utils");
+addpath("./utils/lower_utils/lower_utils");
+arg_list=argv();
+Lh=sscanf(arg_list{1}, "%d", "C");
+
+INCREMENT_NUM=2**(Lh-1);
+BRANCH_NUM=2**(Lh+1);
+PATHS_NUM=2**(Lh);
+
+load tests/data/rhh.dat;
+load tests/data/normal_burst.dat;
+
+[r BURST_SIZE] = size(normal_burst);
+
+SYMBOLS = make_symbols(Lh);
+START = make_start(Lh,SYMBOLS);
+STOP = make_stops(Lh,SYMBOLS);
+
+[increment,  pm_candidates_imag, pm_candidates_real] = equations_gen(Lh);
+
+f_name="test";
+test_file = fopen([f_name '.cpp'],'w');
+
+print_matrix_type=sprintf("   printf(\"# name: path_metrics_test_result\\n# type: matrix\\n# rows: %d\\n# columns: %d\\n\");\n", BURST_SIZE, PATHS_NUM);;
+
+print_path_metrics=[ "\n\
+      for(i=0; i<" int2str(PATHS_NUM) "; i++){\n\
+         printf(\" %0.6f\", new_path_metrics[i]);\n\
+      }\n\
+      printf(\"\\n\");\n\n" ];
+
+viterbi_detector = viterbi_generator(Lh,  print_matrix_type, print_path_metrics);
+
+fprintf(test_file, "\
+#include <stdio.h>\n", BURST_SIZE);
+
+fprintf(test_file, "%s", viterbi_detector);
+
+fprintf(test_file, [ "\
+int main()\n\
+{\n\
+   gr_complex rhh[" int2str(Lh+1) "];\n\
+   gr_complex input[BURST_SIZE];\n\
+   float output[BURST_SIZE];\n\
+   float path_metrics[" int2str(PATHS_NUM) "];\n\
+   unsigned int i;\n\n" ]);
+
+for i=1:Lh+1,
+  fprintf(test_file,"   rhh[%d] = gr_complex(%0.10f,%0.10f);\n",i-1, real(Rhh(i)), imag(Rhh(i)));
+end
+
+for i=1:BURST_SIZE,
+  fprintf(test_file,"   input[%d] = gr_complex(%0.10f,%0.10f);\n",i-1, real(normal_burst(i)), imag(normal_burst(i)));
+end
+
+[STOPS_NUM c] = size(STOP);
+
+stop_states=["   unsigned int stop_states[" int2str(STOPS_NUM) "] = { "];
+for i=1:STOPS_NUM,
+  stop_states=[ stop_states int2str(ceil(STOP(i)/2)-1) ", "];
+end
+stop_states=[ stop_states " };\n\n" ];
+
+fprintf(test_file, stop_states);
+
+fprintf(test_file, ["   viterbi_detector(input, BURST_SIZE, rhh, " int2str(ceil(START/2)-1) ", stop_states, " int2str(STOPS_NUM) ", output);" ]);
+
+print_output=[ "\n\
+      printf(\"# name: output\\n# type: matrix\\n# rows: 1\\n# columns: " int2str(BURST_SIZE) "\\n\");\n\
+      for(i=0; i<BURST_SIZE ; i++){\n\
+         printf(\" %d\\n\", output[i]>0);\n\
+      }\n\
+      printf(\"\\n\");\n" ];
+
+fprintf(test_file, "%s", print_output);
+
+fprintf(test_file, "\n}\n");
+
+
diff --git a/viterbi_generator/tests/utils/make_increment.m b/viterbi_generator/tests/utils/make_increment.m
new file mode 100644
index 0000000..91cc0ae
--- /dev/null
+++ b/viterbi_generator/tests/utils/make_increment.m
@@ -0,0 +1,70 @@
+function [ INCREMENT ] = make_increment(SYMBOLS,NEXT,Rhh)
+%
+% MAKE_INCREMENT:
+%           This function returns a lookuptable containing the
+%           metric increments related to moving from state n to m.
+%           The data is arranged so that the increment accosiated 
+%           with a move from state n to m is located in 
+%           INCREMENT(n,m). To minimize computations only legal
+%           transitions are considdered.
+%
+% SYNTAX:   [ INCREMENT ] = make_increment(SYMBOLS,NEXT,Rhh)
+%
+% INPUT:    SYMBOLS: The table of symbols corresponding the the state-
+%                    numbers.
+%           NEXT:    A transition table containing the next legal
+%                    states, as it is generated by the code make_next.
+%           Rhh:     The autocorrelation as estimated by mf.m.
+%
+% OUTPUT:   INCREMENT:
+%                    The increment table as described above.
+%
+% SUB_FUNC: None
+%
+% WARNINGS: There is no syntax checking on input or output.
+%
+% TEST(S):  By hand, against expected values.
+%
+% AUTOR:    Jan H. Mikkelsen / Arne Norre Ekstrøm
+% EMAIL:    hmi@kom.auc.dk / aneks@kom.auc.dk
+%
+% $Id: make_increment.m,v 1.6 1997/09/22 11:39:34 aneks Exp $
+
+% IN THIS PEACE OF CODE THE SYNTAX CHECKING IS MINIMAL
+% THIS HAS BEEN CHOSEN TO AVOID THE OVERHEAD. RECALL THAT
+% THIS CODE IS EXECUTED EACH TIME A BURST IS RECEIVED.
+
+% FIND THE NUMBER OF SYMBOLS THAT WE HAVE
+%
+[M,Lh]=size(SYMBOLS);
+
+% INITIALIZE THE INCREMENT MATRIX
+%
+INCREMENT=zeros(M);
+
+% RECALL THAT THE I SEQUENCE AS IT IS STORED IN STORED AS:
+% [ I(n-1) I(n-2) I(n-3) ... I(n-Lh) ]
+%
+% ALSO RECALL THAT Rhh IS STORED AS:
+% [ Rhh(1) Rhh(2) Rhh(3) ... Rhh(Lh) ]
+%
+% THE FORMULA TO USE IS:
+% INCREMENT(n,m)
+% =
+% real(conj(I(n))*(I(n-Lh)*Rhh(Lh)+I(n-Lh+1)*Rhh(Lh-1)+...+I(n-1)*Rhh(1))
+%
+% THEY CAN THUS BE MULTIPLIED DIRECTLY WITH EACH OTHER
+
+% LOOP OVER THE STATES, AS FOUND IN THE ROWS IN SYMBOLS.
+%
+for n=1:M, 
+  % ONLY TWO LEGAL NEXT STATES EXIST, SO THE LOOP IS UNROLLED
+  %
+  m=NEXT(n,1);
+
+  INCREMENT(n,m)=real((conj(SYMBOLS(m,1))*SYMBOLS(n,:))*Rhh(2:Lh+1).');
+  m=NEXT(n,2);
+
+  INCREMENT(n,m)=real((conj(SYMBOLS(m,1))*SYMBOLS(n,:))*Rhh(2:Lh+1).');
+end
+
diff --git a/viterbi_generator/tests/utils/make_next.m b/viterbi_generator/tests/utils/make_next.m
new file mode 100644
index 0000000..f5af8dc
--- /dev/null
+++ b/viterbi_generator/tests/utils/make_next.m
@@ -0,0 +1,54 @@
+function [ NEXT ] = make_next(SYMBOLS)
+%
+% MAKE_NEXT:
+%           This function returns a lookuptable containing a mapping
+%           between the present state and the legal next states.
+%           Each row correspond to a state, and the two legal states
+%           related to state n is located in NEXT(n,1) and in
+%           NEXT(n,2). States are represented by their related 
+%           numbers.
+%
+% SYNTAX:   [ NEXT ] = make_next(SYMBOLS)
+%
+% INPUT:    SYMBOLS: The table of symbols corresponding the the state-
+%                    numbers.
+%
+% OUTPUT:   NEXT:    The transition table describing the legal next
+%		     states asdescribed above.
+%
+% SUB_FUNC: None
+%
+% WARNINGS: None
+%
+% TEST(S):  The function has been verified to return the expected
+%           results.
+%
+% AUTOR:    Jan H. Mikkelsen / Arne Norre Ekstrøm
+% EMAIL:    hmi@kom.auc.dk / aneks@kom.auc.dk
+%
+% $Id: make_next.m,v 1.3 1997/09/22 08:13:29 aneks Exp $
+
+% FIRST WE NEED TO FIND THE NUMBER OF LOOPS WE SHOULD RUN.
+% THIS EQUALS THE NUMBER OF SYMBOLS. ALSO MAXSUM IS NEEDED FOR
+% LATER OPERATIONS.
+%
+[ states , maxsum ]=size(SYMBOLS);
+
+search_matrix=SYMBOLS(:,2:maxsum);
+maxsum=maxsum-1;
+
+% LOOP OVER THE SYMBOLS.
+%
+for this_state=1:states,
+  search_vector=SYMBOLS(this_state,1:maxsum);
+  k=0;
+  for search=1:states,
+    if (sum(search_matrix(search,:)==search_vector)==maxsum)
+      k=k+1;
+      NEXT(this_state,k)=search;
+      if k > 2,
+	error('Error: identified too many next states');
+      end
+    end
+  end
+end
\ No newline at end of file
diff --git a/viterbi_generator/tests/utils/make_previous.m b/viterbi_generator/tests/utils/make_previous.m
new file mode 100644
index 0000000..678fa43
--- /dev/null
+++ b/viterbi_generator/tests/utils/make_previous.m
@@ -0,0 +1,54 @@
+function [ PREVIOUS ] = make_previous(SYMBOLS)
+%
+% MAKE_PREVIOUS:       
+%           This function returns a lookuptable containing a mapping
+%           between the present state and the legal previous states.
+%           Each row correspond to a state, and the two legal states
+%           related to state n is located in PREVIOUS(n,1) and in
+%           previous(n,2). States are represented by their related 
+%           numbers.
+%
+% SYNTAX:   [ PREVIOUS ] = make_previous(SYMBOLS)
+%
+% INPUT:    SYMBOLS: The table of symbols corresponding the the state-
+%                    numbers.
+%
+% OUTPUT:   PREVIOUS:
+%                    The transition table describing the legal previous
+%		     states asdescribed above.
+%
+% SUB_FUNC: None
+%
+% WARNINGS: None
+%
+% TEST(S):  Verified against expected result.
+%
+% AUTOR:    Jan H. Mikkelsen / Arne Norre Ekstrøm
+% EMAIL:    hmi@kom.auc.dk / aneks@kom.auc.dk
+%
+% $Id: make_previous.m,v 1.3 1997/09/22 08:14:27 aneks Exp $
+
+% FIRST WE NEED TO FIND THE NUMBER OF LOOPS WE SHOULD RUN.
+% THIS EQUALS THE NUMBER OF SYMBOLS. ALSO MAXSUM IS NEEDED FOR
+% LATER OPERATIONS.
+%
+[ states , maxsum ]=size(SYMBOLS);
+
+maxsum=maxsum-1;
+search_matrix=SYMBOLS(:,1:maxsum);
+
+% LOOP OVER THE SYMBOLS.
+%
+for this_state=1:states,
+  search_vector=SYMBOLS(this_state,2:maxsum+1);
+  k=0;
+  for search=1:states,
+    if (sum(search_matrix(search,:)==search_vector)==maxsum)
+      k=k+1;
+      PREVIOUS(this_state,k)=search;
+      if k > 2,
+	error('Error: identified too many previous states');
+      end
+    end
+  end
+end
\ No newline at end of file
diff --git a/viterbi_generator/tests/utils/make_start.m b/viterbi_generator/tests/utils/make_start.m
new file mode 100644
index 0000000..83275fd
--- /dev/null
+++ b/viterbi_generator/tests/utils/make_start.m
@@ -0,0 +1,63 @@
+function [ START ] = make_start(Lh,SYMBOLS)
+%
+% MAKE_START:
+%           This code returns a statenumber corresponding to the start
+%           state as it is found from Lh. The method is to use the table
+%           of symbolic start states as it is listed in the report made 
+%           by 95gr870T. For the table lookups are made in SYMBOLS. in 
+%           order to map from the symbol representation to the state number 
+%           representation.
+%
+% SYNTAX:   [ START ] = make_start(Lh,SYMBOLS)
+%
+% INPUT:    SYMBOLS: The table of symbols corresponding the the state-
+%                    numbers.
+%           Lh:      Length of the estimated impulseresponse.
+%
+% OUTPUT:   START:   The number representation of the legal start state.
+%
+% SUB_FUNC: None
+%
+% WARNINGS: The table of symbolic representations has not been verified
+%           but is used directly as it is listed in the report made 
+%           by 95gr870T.
+%
+% TEST(S):  The function has been verified to return a state number
+%           which matches the symbolic representation.
+%
+% AUTOR:    Jan H. Mikkelsen / Arne Norre Ekstrøm
+% EMAIL:    hmi@kom.auc.dk / aneks@kom.auc.dk
+%
+% $Id: make_start.m,v 1.2 1997/09/22 11:40:17 aneks Exp $
+
+% WE HAVEN'T FOUND IT YET.
+%
+START_NOT_FOUND = 1;
+
+% OBTAIN THE SYMBOLS FROM Lh. THIS IS THE TABLE LISTED IN THE REPORT MADE 
+% BY 95gr870T. (SATEREPRESENTATION IS SLIGHTLY CHANGED).
+%
+if Lh==1,
+  start_symbols = [ 1 ];
+elseif Lh==2,
+  start_symbols = [ 1 -j ];
+elseif Lh==3,
+  start_symbols = [ 1 -j -1 ];
+elseif Lh==4,
+  start_symbols = [ 1 -j -1 j ];
+elseif Lh==5,
+  start_symbols = [ 1 -j -1 j 1];
+else
+  fprintf('\n\nError: Illegal value of Lh, terminating...');
+end
+
+% NOW MAP FROM THE SYMBOLS TO A STATE NUMBER BY SEARCHING 
+% SYMBOLS.
+%
+START=0;
+while START_NOT_FOUND,
+  START=START+1;
+  if sum(SYMBOLS(START,:)==start_symbols)==Lh,
+    START_NOT_FOUND=0;
+  end
+end
diff --git a/viterbi_generator/tests/utils/make_stops.m b/viterbi_generator/tests/utils/make_stops.m
new file mode 100644
index 0000000..98734c9
--- /dev/null
+++ b/viterbi_generator/tests/utils/make_stops.m
@@ -0,0 +1,67 @@
+function [ STOPS ] = make_stops(Lh,SYMBOLS)
+%
+% MAKE_STOPS:
+%           This code returns a statenumber corresponding to the set of
+%           legal stop states as found from Lh. The method is to use the table
+%           of symbolic stop states as it is listed in the report made 
+%           by 95gr870T. For the table lookups are made in SYMBOLS. in 
+%           order to map from the symbol representation to the state number 
+%           representation.
+%
+% SYNTAX:   [ STOPS ] = make_stops(Lh,SYMBOLS)
+%
+% INPUT:    SYMBOLS: The table of symbols corresponding the the state-
+%                    numbers.
+%           Lh:      Length of the estimated impulseresponse.
+%
+% OUTPUT:   STOPS:   The number representation of the set of legal stop 
+%                    states.
+%
+% SUB_FUNC: None
+%
+% WARNINGS: The table of symbolic representations has not been verified
+%           but is used directly as it is listed in the report made 
+%           by 95gr870T.
+%
+% TEST(S):  The function has been verified to return a state number
+%           which matches the symbolic representation.
+%
+% AUTOR:    Jan H. Mikkelsen / Arne Norre Ekstrøm
+% EMAIL:    hmi@kom.auc.dk / aneks@kom.auc.dk
+%
+% $Id: make_stops.m,v 1.2 1997/09/22 11:44:21 aneks Exp $
+
+% OBTAIN THE SYMBOLS FROM Lh. THIS IS THE TABLE LISTED IN THE REPORT MADE 
+% BY 95gr870T. (SATEREPRESENTATION IS SLIGHTLY CHANGED).
+%
+if Lh==1,
+  stop_symbols = [ -1 ];
+  count=1;
+elseif Lh==2,
+  stop_symbols = [ -1 j ];
+  count=1;
+elseif Lh==3,
+  stop_symbols = [ -1 j 1 ];
+  count=1;
+elseif Lh==4,
+  stop_symbols = [  [ -1 j 1 j ] ; [ -1 j 1 -j ] ];
+  count=2;
+elseif Lh==5,
+  stop_symbols = [ [ -1 j 1 j -1] ; [ -1 j 1 -j -1] ; [ -1 j 1 j 1] ; [ -1 j 1 -j 1] ];
+  count=2;
+else
+  fprintf('\n\nError: Illegal value of Lh, terminating...');
+end
+
+% NOW THAT WE HAVE THE SYMBOL REPRESENTATION THE REMAINING JOB IS
+% TO MAP THE MSK SYMBOLS TO STATE NUMBERS
+%
+index = 0;
+stops_found=0;
+while stops_found < count,
+  index=index+1;
+  if sum(SYMBOLS(index,:)==stop_symbols(stops_found+1,:))==Lh,
+    stops_found=stops_found+1;
+    STOPS(stops_found)=index;
+  end
+end
diff --git a/viterbi_generator/tests/utils/viterbi_detector.m b/viterbi_generator/tests/utils/viterbi_detector.m
new file mode 100644
index 0000000..31e8f93
--- /dev/null
+++ b/viterbi_generator/tests/utils/viterbi_detector.m
@@ -0,0 +1,218 @@
+function [ rx_burst METRIC] = viterbi_detector(SYMBOLS,NEXT,PREVIOUS,START,STOPS,Y,Rhh)
+%
+% VITERBI_DETECTOR:
+%           This matlab code does the actual detection of the
+%           received sequence. As indicated by the name the algorithm
+%           is the viterbi algorithm, which is a MLSE. At this time 
+%           the approch is to use Ungerboecks modified algorithm, and
+%           to return hard output only.
+%
+% SYNTAX:   [ rx_burst ] 
+%           = 
+%           viterbi_detector(SYMBOLS,NEXT,PREVIOUS,START,STOPS,Y,Rhh)
+%
+% INPUT:    SYMBOLS:  The table of symbols corresponding the the state-
+%                     numbers. Format as made by make_symbols.m
+%           NEXT:     A transition table containing the next legal
+%                     states, as it is generated by the code make_next.m
+%           PREVIOUS: The transition table describing the legal previous
+%		      states as generated by make_previous.m
+%           START:    The start state of the algorithm.
+%           STOPS:    The legal stop states.
+%           Y:        Complex baseband representation of the matched 
+%                     filtered and down converted received signal, as it
+%                     is returned by mf.m
+%           Rhh:      The autocorrelation as estimated by mf.m
+%
+% OUTPUT:   rx_burst: The most likely sequence of symbols.
+%
+% SUB_FUNC: make_increment
+%
+% WARNINGS: None.
+%
+% TEST(S):  Tested with no noise, perfect syncronization, and channel 
+%           estimation/filtering. (Refer to viterbi_ill.m)
+%
+% AUTOR:    Jan H. Mikkelsen / Arne Norre Ekstrøm
+% EMAIL:    hmi@kom.auc.dk / aneks@kom.auc.dk
+%
+% $Id: viterbi_detector.m,v 1.7 1997/11/18 12:41:26 aneks Exp $
+
+% KNOWLEDGE OF Lh AND M IS NEEDED FOR THE ALGORITHM TO OPERATE
+%
+[ M , Lh ] = size(SYMBOLS);
+
+% THE NUMBER OF STEPS IN THE VITERBI
+%
+STEPS=length(Y);
+% INITIALIZE TABLES (THIS YIELDS A SLIGHT SPEEDUP).
+%
+METRIC = zeros(M,STEPS);
+SURVIVOR = zeros(M,STEPS);
+
+% DETERMINE PRECALCULATABLE PART OF METRIC
+%
+INCREMENT=make_increment(SYMBOLS,NEXT,Rhh);
+%INCREMENT
+% THE FIRST THING TO DO IS TO ROLL INTO THE ALGORITHM BY SPREADING OUT 
+% FROM 	THE START STATE TO ALL THE LEGAL STATES. 
+%
+PS=START;
+
+% NOTE THAT THE START STATE IS REFERRED TO AS STATE TO TIME 0
+% AND THAT IT HAS NO METRIC.
+%
+S=NEXT(START,1);
+
+METRIC(S,1)=real(conj(SYMBOLS(S,1))*Y(1))-INCREMENT(PS,S);
+SURVIVOR(S,1)=START;
+
+S=NEXT(START,2);
+METRIC(S,1)=real(conj(SYMBOLS(S,1))*Y(1))-INCREMENT(PS,S);
+SURVIVOR(S,1)=START;
+
+PREVIOUS_STATES=NEXT(START,:);
+
+% MARK THE NEXT STATES AS REAL. N.B: COMPLEX INDICATES THE POLARITY
+% OF THE NEXT STATE, E.G. STATE 2 IS REAL.
+%
+COMPLEX=0;
+
+for N = 2:Lh,
+  if COMPLEX,
+    COMPLEX=0;
+  else
+    COMPLEX=1;
+  end
+  STATE_CNTR=0;
+  for PS = PREVIOUS_STATES,
+    STATE_CNTR=STATE_CNTR+1;
+    S=NEXT(PS,1);
+    METRIC(S,N)=METRIC(PS,N-1)+real(conj(SYMBOLS(S,1))*Y(N))-INCREMENT(PS,S);
+    SURVIVOR(S,N)=PS;
+    USED(STATE_CNTR)=S;
+    STATE_CNTR=STATE_CNTR+1;
+    S=NEXT(PS,2);
+    METRIC(S,N)=METRIC(PS,N-1)+real(conj(SYMBOLS(S,1))*Y(N))-INCREMENT(PS,S);
+    SURVIVOR(S,N)=PS;    
+    USED(STATE_CNTR)=S;
+  end
+  PREVIOUS_STATES=USED;
+end
+% AT ANY RATE WE WILL HAVE PROCESSED Lh STATES AT THIS TIME
+%
+PROCESSED=Lh;
+
+% WE WANT AN EQUAL NUMBER OF STATES TO BE REMAINING. THE NEXT LINES ENSURE
+% THIS.
+%
+
+if ~COMPLEX,
+  COMPLEX=1;
+  PROCESSED=PROCESSED+1;
+  N=PROCESSED;
+  for S = 2:2:M,
+    PS=PREVIOUS(S,1);
+    M1=METRIC(PS,N-1)+real(conj(SYMBOLS(S,1))*Y(N)-INCREMENT(PS,S));
+    PS=PREVIOUS(S,2);
+    M2=METRIC(PS,N-1)+real(conj(SYMBOLS(S,1))*Y(N)-INCREMENT(PS,S)); 
+    if M1 > M2,
+      METRIC(S,N)=M1;
+      SURVIVOR(S,N)=PREVIOUS(S,1);
+    else
+      METRIC(S,N)=M2;
+      SURVIVOR(S,N)=PREVIOUS(S,2);
+    end
+  end
+end
+
+% NOW THAT WE HAVE MADE THE RUN-IN THE REST OF THE METRICS ARE
+% CALCULATED IN THE STRAIGHT FORWARD MANNER. OBSERVE THAT ONLY
+% THE RELEVANT STATES ARE CALCULATED, THAT IS REAL FOLLOWS COMPLEX
+% AND VICE VERSA.
+%
+N=PROCESSED+1;
+while N <= STEPS,
+  for S = 1:2:M-1,
+    PS=PREVIOUS(S,1);
+    M1=METRIC(PS,N-1)+real(conj(SYMBOLS(S,1))*Y(N)-INCREMENT(PS,S));
+    PS=PREVIOUS(S,2);
+    M2=METRIC(PS,N-1)+real(conj(SYMBOLS(S,1))*Y(N)-INCREMENT(PS,S)); 
+    if M1 > M2,
+      METRIC(S,N)=M1;
+      SURVIVOR(S,N)=PREVIOUS(S,1);
+    else
+      METRIC(S,N)=M2;
+      SURVIVOR(S,N)=PREVIOUS(S,2);
+    end   
+  end
+  N=N+1;
+  for S = 2:2:M,
+    PS=PREVIOUS(S,1);
+    M1=METRIC(PS,N-1)+real(conj(SYMBOLS(S,1))*Y(N)-INCREMENT(PS,S));
+    PS=PREVIOUS(S,2);
+    M2=METRIC(PS,N-1)+real(conj(SYMBOLS(S,1))*Y(N)-INCREMENT(PS,S)); 
+    if M1 > M2,
+      METRIC(S,N)=M1;
+      SURVIVOR(S,N)=PREVIOUS(S,1);
+    else
+      METRIC(S,N)=M2;
+      SURVIVOR(S,N)=PREVIOUS(S,2);
+    end   
+  end
+  N=N+1;
+end  
+
+
+% HAVING CALCULATED THE METRICS, THE MOST PROBABLE STATESEQUENCE IS
+% INITIALIZED BY CHOOSING THE HIGHEST METRIC AMONG THE LEGAL STOP 
+% STATES.
+%
+BEST_LEGAL=0;
+for FINAL = STOPS,
+  if METRIC(FINAL,STEPS) > BEST_LEGAL,
+    S=FINAL;
+    BEST_LEGAL=METRIC(FINAL,STEPS);
+  end
+end
+
+% UNCOMMENT FOR TEST OF METRIC
+%
+% METRIC
+% BEST_LEGAL
+% S
+% pause
+
+% HAVING FOUND THE FINAL STATE, THE MSK SYMBOL SEQUENCE IS ESTABLISHED
+%
+
+IEST(STEPS)=SYMBOLS(S,1);
+N=STEPS-1;
+while N > 0,
+
+%  if(N>STEPS-40),
+%    previo=ceil(S/2)
+%  end
+  S=SURVIVOR(S,N+1);
+  IEST(N)=SYMBOLS(S,1);
+  N=N-1;
+end
+
+% THE ESTIMATE IS NOW FOUND FROM THE FORMULA:
+% IEST(n)=j*rx_burst(n)*rx_burst(n-1)*IEST(n-1)
+% THE FORMULA IS REWRITTEN AS:
+% rx_burst(n)=IEST(n)/(j*rx_burst(n-1)*IEST(n-1))
+% FOR INITIALIZATION THE FOLLOWING IS USED:
+% IEST(0)=1 og rx_burst(0)=1
+%
+rx_burst(1)=IEST(1)/(j*1*1);
+for n = 2:STEPS,
+  rx_burst(n)=IEST(n)/(j*rx_burst(n-1)*IEST(n-1));
+end
+
+% rx_burst IS POLAR (-1 AND 1), THIS TRANSFORMS IT TO
+% BINARY FORM (0 AND 1).
+%
+
+rx_burst=(rx_burst+1)./2;
+
diff --git a/viterbi_generator/tests/utils/viterbi_init.m b/viterbi_generator/tests/utils/viterbi_init.m
new file mode 100644
index 0000000..a43b801
--- /dev/null
+++ b/viterbi_generator/tests/utils/viterbi_init.m
@@ -0,0 +1,38 @@
+function [ SYMBOLS , PREVIOUS , NEXT , START , STOPS ] = viterbi_init(Lh)
+% VITERBI_INIT:
+%           This function returns the tables which are used by the 
+%           viterbi demodulator which is implemented in the GSMsim
+%           package.
+%
+% SYNTAX:   [ SYMBOLS , PREVIOUS , NEXT , START , STOPS ]
+%           = 
+%           viterbi_init(Lh)
+%
+% INPUT:    Lh:       The length of the channel impulse response
+%                     minus one.
+%
+% OUTPUT:   SYMBOLS:  Statenumber to MSK-symbols mapping table.
+%           PREVIOUS: This state to legal previous state mapping table.
+%           NEXT:     This state to legal next state mapping table.
+%           START:    The start state of the viterbi algorithm.
+%           STOPS:    The set of legal stop states for the viterbi 
+%                     algorithm.
+%
+% GLOBAL:   None
+%
+% SUB_FUNC: make_symbols,make_previous,make_next,make_start,make_stops
+%
+% WARNINGS: None
+% 
+% TEST:     Verified that the function actually runs the subfunctions.
+%
+% AUTHOR:   Jan H. Mikkelsen / Arne Norre Ekstrøm
+% EMAIL:    hmi@kom.auc.dk / aneks@kom.auc.dk
+%
+% $Id: viterbi_init.m,v 1.4 1998/02/12 10:52:15 aneks Exp $
+
+SYMBOLS = make_symbols(Lh);
+PREVIOUS = make_previous(SYMBOLS);
+NEXT = make_next(SYMBOLS);
+START = make_start(Lh,SYMBOLS);
+STOPS = make_stops(Lh,SYMBOLS);