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Add some experimental routines.
git-svn-id: svn+ssh://svn.code.sf.net/p/wsjt/wsjt/branches/wsjtx@7628 ab8295b8-cf94-4d9e-aec4-7959e3be5d79
This commit is contained in:
Steven Franke
parent
6a1fe0012b
commit
c101181938
@ -299,6 +299,7 @@ set (wsjt_FSRCS
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lib/badmsg.f90
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lib/bpdecode40.f90
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lib/bpdecode144.f90
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lib/fsk4hf/bpdecode120.f90
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lib/fsk4hf/bpdecode168.f90
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lib/baddata.f90
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lib/ccf2.f90
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@ -324,6 +325,7 @@ set (wsjt_FSRCS
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lib/encode4.f90
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lib/encode_msk40.f90
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lib/encode_msk144.f90
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lib/fsk4hf/encode120.f90
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lib/fsk4hf/encode168.f90
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lib/entail.f90
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lib/ephem.f90
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@ -390,6 +392,7 @@ set (wsjt_FSRCS
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lib/jt9_decode.f90
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lib/jt9fano.f90
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lib/ldpcsim144.f90
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lib/fsk4hf/ldpcsim120.f90
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lib/fsk4hf/ldpcsim168.f90
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lib/ldpcsim40.f90
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lib/libration.f90
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@ -1084,10 +1087,13 @@ target_link_libraries (jt65 wsjt_fort wsjt_cxx)
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add_executable (ldpcsim40 lib/ldpcsim40.f90 wsjtx.rc)
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target_link_libraries (ldpcsim40 wsjt_fort wsjt_cxx)
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add_executable (ldpcsim120 lib/fsk4hf/ldpcsim120.f90 lib/crc.cpp wsjtx.rc)
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target_link_libraries (ldpcsim120 wsjt_fort wsjt_cxx)
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add_executable (ldpcsim144 lib/ldpcsim144.f90 wsjtx.rc)
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target_link_libraries (ldpcsim144 wsjt_fort wsjt_cxx)
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add_executable (ldpcsim168 lib/fsk4hf/ldpcsim168.f90 wsjtx.rc)
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add_executable (ldpcsim168 lib/fsk4hf/ldpcsim168.f90 lib/crc.cpp wsjtx.rc)
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target_link_libraries (ldpcsim168 wsjt_fort wsjt_cxx)
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add_executable (msk144sim lib/msk144sim.f90 wsjtx.rc)
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@ -5,6 +5,8 @@ extern "C"
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{
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short crc12 (unsigned char const * data, int length);
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bool crc12_check (unsigned char const * data, int length);
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short crc10 (unsigned char const * data, int length);
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bool crc10_check (unsigned char const * data, int length);
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}
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// assumes CRC is last 16 bits of the data and is set to zero
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@ -18,3 +20,13 @@ bool crc12_check (unsigned char const * data, int length)
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{
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return !boost::augmented_crc<12, 0xc06> (data, length);
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}
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short crc10 (unsigned char const * data, int length)
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{
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return boost::augmented_crc<10, 0x08f> (data, length);
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}
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bool crc10_check (unsigned char const * data, int length)
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{
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return !boost::augmented_crc<10, 0x08f> (data, length);
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}
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17
lib/crc.f90
17
lib/crc.f90
@ -16,5 +16,22 @@ module crc
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type (c_ptr), value :: data
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integer (c_int), value :: length
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end function crc12_check
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function crc10 (data, length) bind (C, name="crc10")
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use, intrinsic :: iso_c_binding, only: c_short, c_ptr, c_int
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implicit none
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integer (c_short) :: crc10
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type (c_ptr), value :: data
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integer (c_int), value :: length
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end function crc10
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function crc10_check (data, length) bind (C, name="crc10_check")
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use, intrinsic :: iso_c_binding, only: c_bool, c_ptr, c_int
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implicit none
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logical (c_bool) :: crc10_check
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type (c_ptr), value :: data
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integer (c_int), value :: length
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end function crc10_check
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end interface
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end module crc
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306
lib/fsk4hf/bpdecode120.f90
Normal file
306
lib/fsk4hf/bpdecode120.f90
Normal file
@ -0,0 +1,306 @@
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subroutine bpdecode120(llr,apmask,maxiterations,decoded,niterations)
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!
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! A log-domain belief propagation decoder for the (120,60) code.
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!
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integer, parameter:: N=120, K=60, M=N-K
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integer*1 codeword(N),cw(N),apmask(N)
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integer colorder(N)
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integer*1 decoded(K)
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integer Nm(7,M) ! 5, 6, or 7 bits per check
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integer Mn(3,N) ! 3 checks per bit
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integer synd(M)
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real tov(3,N)
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real toc(7,M)
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real tanhtoc(7,M)
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real zn(N)
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real llr(N)
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real Tmn
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integer nrw(M)
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data colorder/ &
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0,1,2,21,3,4,5,6,7,8,20,10,9,11,12,23,13,28,14,31, &
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15,16,22,26,17,30,18,29,25,32,41,34,19,33,27,36,38,43,42,24, &
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37,39,45,40,35,44,47,46,50,51,53,48,52,56,54,57,55,49,58,61, &
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60,59,62,63,64,65,66,67,68,69,70,71,72,73,74,75,76,77,78,79, &
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80,81,82,83,84,85,86,87,88,89,90,91,92,93,94,95,96,97,98,99, &
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100,101,102,103,104,105,106,107,108,109,110,111,112,113,114,115,116,117,118,119/
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data Mn/ &
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1, 18, 48, &
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2, 4, 51, &
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3, 23, 47, &
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5, 36, 42, &
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6, 43, 49, &
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7, 24, 55, &
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8, 35, 60, &
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9, 26, 30, &
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10, 29, 45, &
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11, 13, 46, &
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12, 53, 54, &
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14, 20, 57, &
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15, 16, 58, &
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17, 39, 44, &
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19, 37, 41, &
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21, 28, 34, &
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22, 50, 59, &
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25, 31, 52, &
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27, 32, 38, &
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33, 40, 56, &
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1, 11, 47, &
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2, 10, 16, &
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3, 12, 27, &
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4, 24, 28, &
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5, 23, 60, &
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6, 29, 39, &
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7, 31, 54, &
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8, 50, 56, &
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9, 13, 14, &
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15, 22, 41, &
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17, 26, 40, &
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18, 25, 45, &
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19, 20, 55, &
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21, 30, 36, &
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32, 49, 59, &
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33, 53, 58, &
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34, 38, 46, &
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29, 35, 57, &
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37, 43, 48, &
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42, 51, 52, &
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7, 11, 44, &
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1, 42, 58, &
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2, 13, 49, &
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3, 20, 40, &
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4, 18, 56, &
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5, 45, 55, &
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6, 21, 31, &
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8, 46, 52, &
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9, 12, 48, &
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10, 37, 38, &
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14, 15, 25, &
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16, 17, 60, &
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19, 39, 53, &
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22, 44, 51, &
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23, 28, 41, &
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24, 32, 35, &
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26, 45, 59, &
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27, 33, 36, &
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30, 47, 54, &
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34, 50, 57, &
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33, 43, 55, &
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1, 41, 57, &
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2, 40, 54, &
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3, 6, 24, &
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4, 11, 59, &
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5, 13, 56, &
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7, 16, 34, &
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8, 19, 26, &
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9, 31, 58, &
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10, 21, 53, &
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12, 22, 60, &
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14, 38, 51, &
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15, 43, 46, &
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17, 48, 50, &
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18, 27, 39, &
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20, 28, 44, &
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23, 25, 49, &
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4, 29, 36, &
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30, 32, 52, &
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35, 37, 47, &
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39, 42, 59, &
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1, 21, 40, &
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2, 50, 55, &
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3, 8, 10, &
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5, 31, 37, &
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6, 14, 60, &
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7, 36, 49, &
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9, 34, 39, &
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11, 19, 25, &
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12, 52, 57, &
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13, 22, 29, &
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15, 30, 56, &
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16, 18, 20, &
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17, 24, 46, &
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23, 38, 58, &
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26, 28, 43, &
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2, 27, 41, &
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5, 32, 44, &
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33, 47, 51, &
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35, 48, 53, &
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42, 43, 54, &
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34, 45, 47, &
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1, 8, 49, &
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3, 14, 59, &
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4, 31, 46, &
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6, 20, 50, &
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7, 26, 53, &
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9, 10, 36, &
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11, 58, 60, &
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12, 21, 45, &
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13, 28, 33, &
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15, 17, 35, &
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16, 38, 52, &
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18, 41, 54, &
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19, 23, 32, &
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22, 40, 55, &
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24, 25, 42, &
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26, 27, 56, &
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29, 44, 54, &
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30, 37, 55/
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data Nm/ &
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1, 21, 42, 62, 82, 103, 0, &
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2, 22, 43, 63, 83, 97, 0, &
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3, 23, 44, 64, 84, 104, 0, &
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2, 24, 45, 65, 78, 105, 0, &
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4, 25, 46, 66, 85, 98, 0, &
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5, 26, 47, 64, 86, 106, 0, &
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6, 27, 41, 67, 87, 107, 0, &
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7, 28, 48, 68, 84, 103, 0, &
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8, 29, 49, 69, 88, 108, 0, &
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9, 22, 50, 70, 84, 108, 0, &
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10, 21, 41, 65, 89, 109, 0, &
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11, 23, 49, 71, 90, 110, 0, &
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10, 29, 43, 66, 91, 111, 0, &
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12, 29, 51, 72, 86, 104, 0, &
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13, 30, 51, 73, 92, 112, 0, &
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13, 22, 52, 67, 93, 113, 0, &
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14, 31, 52, 74, 94, 112, 0, &
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1, 32, 45, 75, 93, 114, 0, &
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15, 33, 53, 68, 89, 115, 0, &
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12, 33, 44, 76, 93, 106, 0, &
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16, 34, 47, 70, 82, 110, 0, &
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17, 30, 54, 71, 91, 116, 0, &
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3, 25, 55, 77, 95, 115, 0, &
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6, 24, 56, 64, 94, 117, 0, &
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18, 32, 51, 77, 89, 117, 0, &
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8, 31, 57, 68, 96, 107, 118, &
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19, 23, 58, 75, 97, 118, 0, &
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16, 24, 55, 76, 96, 111, 0, &
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9, 26, 38, 78, 91, 119, 0, &
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8, 34, 59, 79, 92, 120, 0, &
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18, 27, 47, 69, 85, 105, 0, &
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19, 35, 56, 79, 98, 115, 0, &
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20, 36, 58, 61, 99, 111, 0, &
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16, 37, 60, 67, 88, 102, 0, &
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7, 38, 56, 80, 100, 112, 0, &
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4, 34, 58, 78, 87, 108, 0, &
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15, 39, 50, 80, 85, 120, 0, &
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19, 37, 50, 72, 95, 113, 0, &
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14, 26, 53, 75, 81, 88, 0, &
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20, 31, 44, 63, 82, 116, 0, &
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15, 30, 55, 62, 97, 114, 0, &
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4, 40, 42, 81, 101, 117, 0, &
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5, 39, 61, 73, 96, 101, 0, &
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14, 41, 54, 76, 98, 119, 0, &
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9, 32, 46, 57, 102, 110, 0, &
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10, 37, 48, 73, 94, 105, 0, &
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3, 21, 59, 80, 99, 102, 0, &
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1, 39, 49, 74, 100, 0, 0, &
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5, 35, 43, 77, 87, 103, 0, &
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17, 28, 60, 74, 83, 106, 0, &
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2, 40, 54, 72, 99, 0, 0, &
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18, 40, 48, 79, 90, 113, 0, &
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11, 36, 53, 70, 100, 107, 0, &
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11, 27, 59, 63, 101, 114, 119, &
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6, 33, 46, 61, 83, 116, 120, &
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20, 28, 45, 66, 92, 118, 0, &
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12, 38, 60, 62, 90, 0, 0, &
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13, 36, 42, 69, 95, 109, 0, &
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17, 35, 57, 65, 81, 104, 0, &
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7, 25, 52, 71, 86, 109, 0/
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data nrw/ &
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6,6,6,6,6,6,6,6,6,6,6,6,6,6,6,6,6,6,6,6, &
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6,6,6,6,6,7,6,6,6,6,6,6,6,6,6,6,6,6,6,6, &
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6,6,6,6,6,6,6,5,6,6,5,6,6,7,7,6,5,6,6,6/
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ncw=3
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toc=0
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tov=0
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tanhtoc=0
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!write(*,*) llr
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! initialize messages to checks
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do j=1,M
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do i=1,nrw(j)
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toc(i,j)=llr((Nm(i,j)))
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enddo
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enddo
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ncnt=0
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do iter=0,maxiterations
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! Update bit log likelihood ratios (tov=0 in iteration 0).
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do i=1,N
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if( apmask(i) .ne. 1 ) then
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zn(i)=llr(i)+sum(tov(1:ncw,i))
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else
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zn(i)=llr(i)
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endif
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enddo
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! Check to see if we have a codeword (check before we do any iteration).
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cw=0
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where( zn .gt. 0. ) cw=1
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ncheck=0
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do i=1,M
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synd(i)=sum(cw(Nm(1:nrw(i),i)))
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if( mod(synd(i),2) .ne. 0 ) ncheck=ncheck+1
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! if( mod(synd(i),2) .ne. 0 ) write(*,*) 'check ',i,' unsatisfied'
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enddo
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!write(*,*) 'number of unsatisfied parity checks ',ncheck
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if( ncheck .eq. 0 ) then ! we have a codeword - reorder the columns and return it
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niterations=iter
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codeword=cw(colorder+1)
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decoded=codeword(M+1:N)
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return
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endif
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if( iter.gt.0 ) then ! this code block implements an early stopping criterion
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nd=ncheck-nclast
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if( nd .lt. 0 ) then ! # of unsatisfied parity checks decreased
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ncnt=0 ! reset counter
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else
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ncnt=ncnt+1
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endif
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! write(*,*) iter,ncheck,nd,ncnt
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if( ncnt .ge. 3 .and. iter .ge. 5 .and. ncheck .gt. 10) then
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niterations=-1
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return
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endif
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endif
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nclast=ncheck
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! Send messages from bits to check nodes
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do j=1,M
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do i=1,nrw(j)
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ibj=Nm(i,j)
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toc(i,j)=zn(ibj)
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do kk=1,ncw ! subtract off what the bit had received from the check
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if( Mn(kk,ibj) .eq. j ) then
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toc(i,j)=toc(i,j)-tov(kk,ibj)
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endif
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enddo
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enddo
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enddo
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! send messages from check nodes to variable nodes
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do i=1,M
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tanhtoc(1:7,i)=tanh(-toc(1:7,i)/2)
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enddo
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do j=1,N
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do i=1,ncw
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ichk=Mn(i,j) ! Mn(:,j) are the checks that include bit j
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Tmn=product(tanhtoc(1:nrw(ichk),ichk),mask=Nm(1:nrw(ichk),ichk).ne.j)
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call platanh(-Tmn,y)
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! y=atanh(-Tmn)
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tov(i,j)=2*y
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enddo
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enddo
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enddo
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niterations=-1
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return
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end subroutine bpdecode120
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116
lib/fsk4hf/encode120.f90
Normal file
116
lib/fsk4hf/encode120.f90
Normal file
@ -0,0 +1,116 @@
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subroutine encode120(message,codeword)
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! Encode an 60-bit message and return a 120-bit codeword.
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! The generator matrix has dimensions (60,60).
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! The code is a (120,60) regular ldpc code with column weight 3.
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! The code was generated using the PEG algorithm.
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! After creating the codeword, the columns are re-ordered according to
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! "colorder" to make the codeword compatible with the parity-check matrix
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!
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character*15 g(60)
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integer*1 codeword(120)
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integer colorder(120)
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integer*1 gen(60,60)
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integer*1 itmp(120)
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integer*1 message(60)
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integer*1 pchecks(60)
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logical first
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data first/.true./
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data g/ &
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"65541ad98feab6e",&
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"27249940a5895a3",&
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"c80eac7506bf794",&
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"aa50393e3e18d3f",&
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"28527e87d47dced",&
|
||||
"5da0dcaf8db048c",&
|
||||
"d6509a43ca9b01a",&
|
||||
"9a7dadd9c94f1d4",&
|
||||
"bb673d3ba07cf29",&
|
||||
"65e190f2fbed447",&
|
||||
"bc2062a4e520969",&
|
||||
"9e357f3feed059b",&
|
||||
"aa6b59212036a57",&
|
||||
"f78a326722d6565",&
|
||||
"416754bc34c6405",&
|
||||
"f77000b3f04ff67",&
|
||||
"d48fbd7d48c5ab9",&
|
||||
"031ffb5db3a70cb",&
|
||||
"125964e358c4df5",&
|
||||
"bd02c32a5a241ea",&
|
||||
"4c15ecdd8561abd",&
|
||||
"7f0f1b352c7413e",&
|
||||
"26edb94dfd0ae79",&
|
||||
"ca1ba1ee0f8fb24",&
|
||||
"49878a58cb4544c",&
|
||||
"3dbcd0ff821b203",&
|
||||
"c1f4440160d5345",&
|
||||
"b5ea9dc7a5a70ab",&
|
||||
"cebcf7d94976be4",&
|
||||
"0968265f5977c88",&
|
||||
"c5a36937faa78c3",&
|
||||
"f0d4fef11e01c10",&
|
||||
"e35fc0c779bebfe",&
|
||||
"cf49c3eb41a31d5",&
|
||||
"3f0b19352c7013e",&
|
||||
"0e15eccd8521abd",&
|
||||
"dda8dcaf9d3048c",&
|
||||
"fee31438fba59ed",&
|
||||
"ad74a27e939189c",&
|
||||
"736ac01b439106e",&
|
||||
"ab5d2729b29bfa1",&
|
||||
"edf11fb02e5a426",&
|
||||
"5f38be1c93ecc83",&
|
||||
"1e4b3b8dc516b3e",&
|
||||
"84443d8bee614c6",&
|
||||
"d854d9f355ceac4",&
|
||||
"a476b5ece51f0ea",&
|
||||
"831c2b36c4c2f68",&
|
||||
"f485c97a91615ae",&
|
||||
"e9376d828ade9ba",&
|
||||
"cac586f089d3185",&
|
||||
"b8f8c67613dafe2",&
|
||||
"1a3142b401b315d",&
|
||||
"87dbedc43265d2e",&
|
||||
"bb64ec6e652e7da",&
|
||||
"e71bfd4c95dfd38",&
|
||||
"31209af07ad4f75",&
|
||||
"cff1a8ccc5f4978",&
|
||||
"742eded1e1dfefd",&
|
||||
"1cd7154a904dac4"/
|
||||
|
||||
data colorder/ &
|
||||
0,1,2,21,3,4,5,6,7,8,20,10,9,11,12,23,13,28,14,31, &
|
||||
15,16,22,26,17,30,18,29,25,32,41,34,19,33,27,36,38,43,42,24, &
|
||||
37,39,45,40,35,44,47,46,50,51,53,48,52,56,54,57,55,49,58,61, &
|
||||
60,59,62,63,64,65,66,67,68,69,70,71,72,73,74,75,76,77,78,79, &
|
||||
80,81,82,83,84,85,86,87,88,89,90,91,92,93,94,95,96,97,98,99, &
|
||||
100,101,102,103,104,105,106,107,108,109,110,111,112,113,114,115,116,117,118,119/
|
||||
|
||||
save first,gen
|
||||
|
||||
if( first ) then ! fill the generator matrix
|
||||
gen=0
|
||||
do i=1,60
|
||||
do j=1,15
|
||||
read(g(i)(j:j),"(Z1)") istr
|
||||
do jj=1, 4
|
||||
icol=(j-1)*4+jj
|
||||
if( btest(istr,4-jj) ) gen(i,icol)=1
|
||||
enddo
|
||||
enddo
|
||||
enddo
|
||||
first=.false.
|
||||
endif
|
||||
|
||||
do i=1, 60
|
||||
nsum=0
|
||||
do j=1, 60
|
||||
nsum=nsum+message(j)*gen(i,j)
|
||||
enddo
|
||||
pchecks(i)=mod(nsum,2)
|
||||
enddo
|
||||
itmp(1:60)=pchecks
|
||||
itmp(61:120)=message(1:60)
|
||||
codeword(colorder+1)=itmp(1:120)
|
||||
|
||||
return
|
||||
end subroutine encode120
|
||||
219
lib/fsk4hf/ldpcsim120.f90
Normal file
219
lib/fsk4hf/ldpcsim120.f90
Normal file
@ -0,0 +1,219 @@
|
||||
program ldpcsim120
|
||||
! End to end test of the (120,60)/crc10 encoder and decoder.
|
||||
use crc
|
||||
use packjt
|
||||
|
||||
parameter(NRECENT=10)
|
||||
character*12 recent_calls(NRECENT)
|
||||
character*22 msg,msgsent,msgreceived
|
||||
character*8 arg
|
||||
integer*1, allocatable :: codeword(:), decoded(:), message(:)
|
||||
integer*1, target:: i1Msg8BitBytes(9)
|
||||
integer*1, target:: i1Dec8BitBytes(9)
|
||||
integer*1 msgbits(60)
|
||||
integer*1 apmask(120)
|
||||
integer*2 checksum
|
||||
integer colorder(120)
|
||||
integer nerrtot(120),nerrdec(120),nmpcbad(60)
|
||||
logical checksumok,fsk,bpsk
|
||||
real*8, allocatable :: rxdata(:)
|
||||
real, allocatable :: llr(:)
|
||||
|
||||
data colorder/ &
|
||||
0,1,2,21,3,4,5,6,7,8,20,10,9,11,12,23,13,28,14,31, &
|
||||
15,16,22,26,17,30,18,29,25,32,41,34,19,33,27,36,38,43,42,24, &
|
||||
37,39,45,40,35,44,47,46,50,51,53,48,52,56,54,57,55,49,58,61, &
|
||||
60,59,62,63,64,65,66,67,68,69,70,71,72,73,74,75,76,77,78,79, &
|
||||
80,81,82,83,84,85,86,87,88,89,90,91,92,93,94,95,96,97,98,99, &
|
||||
100,101,102,103,104,105,106,107,108,109,110,111,112,113,114,115,116,117,118,119/
|
||||
|
||||
do i=1,NRECENT
|
||||
recent_calls(i)=' '
|
||||
enddo
|
||||
nerrtot=0
|
||||
nerrdec=0
|
||||
nmpcbad=0 ! Used to collect the number of errors in the message+crc part of the codeword
|
||||
|
||||
nargs=iargc()
|
||||
if(nargs.ne.3) then
|
||||
print*,'Usage: ldpcsim niter #trials s '
|
||||
print*,'eg: ldpcsim 10 1000 0.75'
|
||||
return
|
||||
endif
|
||||
call getarg(1,arg)
|
||||
read(arg,*) max_iterations
|
||||
call getarg(2,arg)
|
||||
read(arg,*) ntrials
|
||||
call getarg(3,arg)
|
||||
read(arg,*) s
|
||||
|
||||
fsk=.false.
|
||||
bpsk=.true.
|
||||
|
||||
! don't count crc bits as data bits
|
||||
N=120
|
||||
K=60
|
||||
! scale Eb/No for a (120,50) code
|
||||
rate=real(50)/real(N)
|
||||
|
||||
write(*,*) "rate: ",rate
|
||||
write(*,*) "niter= ",max_iterations," s= ",s
|
||||
|
||||
allocate ( codeword(N), decoded(K), message(K) )
|
||||
allocate ( rxdata(N), llr(N) )
|
||||
|
||||
! The message should be packed into the first 7 bytes
|
||||
i1Msg8BitBytes(1:6)=85
|
||||
i1Msg8BitBytes(7)=64
|
||||
! The CRC will be put into the last 2 bytes
|
||||
i1Msg8BitBytes(8:9)=0
|
||||
checksum = crc10 (c_loc (i1Msg8BitBytes), 9)
|
||||
! For reference, the next 3 lines show how to check the CRC
|
||||
i1Msg8BitBytes(8)=checksum/256
|
||||
i1Msg8BitBytes(9)=iand (checksum,255)
|
||||
checksumok = crc10_check(c_loc (i1Msg8BitBytes), 9)
|
||||
if( checksumok ) write(*,*) 'Good checksum'
|
||||
write(*,*) i1Msg8BitBytes(1:9)
|
||||
|
||||
mbit=0
|
||||
do i=1, 7
|
||||
i1=i1Msg8BitBytes(i)
|
||||
do ibit=1,8
|
||||
mbit=mbit+1
|
||||
msgbits(mbit)=iand(1,ishft(i1,ibit-8))
|
||||
enddo
|
||||
enddo
|
||||
i1=i1Msg8BitBytes(8) ! First 2 bits of crc10 are LSB of this byte
|
||||
do ibit=1,2
|
||||
msgbits(50+ibit)=iand(1,ishft(i1,ibit-2))
|
||||
enddo
|
||||
i1=i1Msg8BitBytes(9) ! Now shift in last 8 bits of the CRC
|
||||
do ibit=1,8
|
||||
msgbits(52+ibit)=iand(1,ishft(i1,ibit-8))
|
||||
enddo
|
||||
|
||||
write(*,*) 'message'
|
||||
write(*,'(9(8i1,1x))') msgbits
|
||||
|
||||
call encode120(msgbits,codeword)
|
||||
call init_random_seed()
|
||||
call sgran()
|
||||
|
||||
write(*,*) 'codeword'
|
||||
write(*,'(15(8i1,1x))') codeword
|
||||
|
||||
write(*,*) "Es/N0 SNR2500 ngood nundetected nbadcrc sigma"
|
||||
do idb = -10, 24
|
||||
db=idb/2.0-1.0
|
||||
! sigma=1/sqrt( 2*rate*(10**(db/10.0)) ) ! to make db represent Eb/No
|
||||
sigma=1/sqrt( 2*(10**(db/10.0)) ) ! db represents Es/No
|
||||
ngood=0
|
||||
nue=0
|
||||
nbadcrc=0
|
||||
nberr=0
|
||||
do itrial=1, ntrials
|
||||
! Create a realization of a noisy received word
|
||||
do i=1,N
|
||||
if( bpsk ) then
|
||||
rxdata(i) = 2.0*codeword(i)-1.0 + sigma*gran()
|
||||
elseif( fsk ) then
|
||||
if( codeword(i) .eq. 1 ) then
|
||||
r1=(1.0 + sigma*gran())**2 + (sigma*gran())**2
|
||||
r2=(sigma*gran())**2 + (sigma*gran())**2
|
||||
elseif( codeword(i) .eq. 0 ) then
|
||||
r2=(1.0 + sigma*gran())**2 + (sigma*gran())**2
|
||||
r1=(sigma*gran())**2 + (sigma*gran())**2
|
||||
endif
|
||||
rxdata(i)=0.35*(sqrt(r1)-sqrt(r2))
|
||||
! rxdata(i)=0.35*(exp(r1)-exp(r2))
|
||||
! rxdata(i)=0.12*(log(r1)-log(r2))
|
||||
endif
|
||||
enddo
|
||||
nerr=0
|
||||
do i=1,N
|
||||
if( rxdata(i)*(2*codeword(i)-1.0) .lt. 0 ) nerr=nerr+1
|
||||
enddo
|
||||
nerrtot(nerr)=nerrtot(nerr)+1
|
||||
nberr=nberr+nerr
|
||||
|
||||
! Correct signal normalization is important for this decoder.
|
||||
! rxav=sum(rxdata)/N
|
||||
! rx2av=sum(rxdata*rxdata)/N
|
||||
! rxsig=sqrt(rx2av-rxav*rxav)
|
||||
! rxdata=rxdata/rxsig
|
||||
! To match the metric to the channel, s should be set to the noise standard deviation.
|
||||
! For now, set s to the value that optimizes decode probability near threshold.
|
||||
! The s parameter can be tuned to trade a few tenth's dB of threshold for an order of
|
||||
! magnitude in UER
|
||||
if( s .lt. 0 ) then
|
||||
ss=sigma
|
||||
else
|
||||
ss=s
|
||||
endif
|
||||
|
||||
llr=2.0*rxdata/(ss*ss)
|
||||
apmask=0
|
||||
|
||||
! max_iterations is max number of belief propagation iterations
|
||||
call bpdecode120(llr, apmask, max_iterations, decoded, niterations)
|
||||
|
||||
|
||||
! If the decoder finds a valid codeword, niterations will be .ge. 0.
|
||||
if( niterations .ge. 0 ) then
|
||||
! Check the CRC
|
||||
do ibyte=1,6
|
||||
itmp=0
|
||||
do ibit=1,8
|
||||
itmp=ishft(itmp,1)+iand(1,decoded((ibyte-1)*8+ibit))
|
||||
enddo
|
||||
i1Dec8BitBytes(ibyte)=itmp
|
||||
enddo
|
||||
i1Dec8BitBytes(7)=decoded(49)*128+decoded(50)*64
|
||||
! Need to pack the received crc into bytes 8 and 9 for crc10_check
|
||||
i1Dec8BitBytes(8)=decoded(51)*2+decoded(52)
|
||||
i1Dec8BitBytes(9)=decoded(53)*128+decoded(54)*64+decoded(55)*32+decoded(56)*16
|
||||
i1Dec8BitBytes(9)=i1Dec8BitBytes(9)+decoded(57)*8+decoded(58)*4+decoded(59)*2+decoded(60)*1
|
||||
ncrcflag=0
|
||||
if( crc10_check( c_loc( i1Dec8BitBytes ), 9 ) ) ncrcflag=1
|
||||
|
||||
if( ncrcflag .ne. 1 ) then
|
||||
nbadcrc=nbadcrc+1
|
||||
endif
|
||||
nueflag=0
|
||||
|
||||
nerrmpc=0
|
||||
do i=1,K ! find number of errors in message+crc part of codeword
|
||||
if( msgbits(i) .ne. decoded(i) ) then
|
||||
nueflag=1
|
||||
nerrmpc=nerrmpc+1
|
||||
endif
|
||||
enddo
|
||||
nmpcbad(nerrmpc)=nmpcbad(nerrmpc)+1 ! This histogram should inform our selection of CRC poly
|
||||
if( ncrcflag .eq. 1 .and. nueflag .eq. 0 ) then
|
||||
ngood=ngood+1
|
||||
nerrdec(nerr)=nerrdec(nerr)+1
|
||||
else if( ncrcflag .eq. 1 .and. nueflag .eq. 1 ) then
|
||||
nue=nue+1;
|
||||
endif
|
||||
endif
|
||||
enddo
|
||||
snr2500=db+10*log10(0.4166/2500.0)
|
||||
pberr=real(nberr)/(real(ntrials*N))
|
||||
write(*,"(f4.1,4x,f5.1,1x,i8,1x,i8,1x,i8,8x,f5.2,8x,e10.3)") db,snr2500,ngood,nue,nbadcrc,ss,pberr
|
||||
|
||||
enddo
|
||||
|
||||
open(unit=23,file='nerrhisto.dat',status='unknown')
|
||||
do i=1,120
|
||||
write(23,'(i4,2x,i10,i10,f10.2)') i,nerrdec(i),nerrtot(i),real(nerrdec(i))/real(nerrtot(i)+1e-10)
|
||||
enddo
|
||||
close(23)
|
||||
open(unit=25,file='nmpcbad.dat',status='unknown')
|
||||
do i=1,60
|
||||
write(25,'(i4,2x,i10)') i,nmpcbad(i)
|
||||
enddo
|
||||
close(25)
|
||||
|
||||
|
||||
|
||||
end program ldpcsim120
|
||||
@ -14,7 +14,7 @@ integer*1 apmask(168)
|
||||
integer*2 checksum
|
||||
integer*4 i4Msg6BitWords(13)
|
||||
integer colorder(168)
|
||||
integer nerrtot(168),nerrdec(168)
|
||||
integer nerrtot(168),nerrdec(168),nmpcbad(84)
|
||||
logical checksumok,fsk,bpsk
|
||||
real*8, allocatable :: rxdata(:)
|
||||
real, allocatable :: llr(:)
|
||||
@ -33,6 +33,7 @@ do i=1,NRECENT
|
||||
enddo
|
||||
nerrtot=0
|
||||
nerrdec=0
|
||||
nmpcbad=0 ! Used to collect the number of errors in the message+crc part of the codeword
|
||||
|
||||
nargs=iargc()
|
||||
if(nargs.ne.3) then
|
||||
@ -47,8 +48,8 @@ read(arg,*) ntrials
|
||||
call getarg(3,arg)
|
||||
read(arg,*) s
|
||||
|
||||
fsk=.true.
|
||||
bpsk=.false.
|
||||
fsk=.false.
|
||||
bpsk=.true.
|
||||
|
||||
! don't count crc bits as data bits
|
||||
N=168
|
||||
@ -62,7 +63,8 @@ write(*,*) "niter= ",max_iterations," s= ",s
|
||||
allocate ( codeword(N), decoded(K), message(K) )
|
||||
allocate ( rxdata(N), llr(N) )
|
||||
|
||||
msg="K1JT K9AN EN50"
|
||||
! msg="K1JT K9AN EN50"
|
||||
msg="G4WJS K9AN EN50"
|
||||
call packmsg(msg,i4Msg6BitWords,itype) !Pack into 12 6-bit bytes
|
||||
call unpackmsg(i4Msg6BitWords,msgsent) !Unpack to get msgsent
|
||||
write(*,*) "message sent ",msgsent
|
||||
@ -180,22 +182,19 @@ do idb = -10, 24
|
||||
! If the decoder finds a valid codeword, niterations will be .ge. 0.
|
||||
if( niterations .ge. 0 ) then
|
||||
call extractmessage168(decoded,msgreceived,ncrcflag,recent_calls,nrecent)
|
||||
if( ncrcflag .eq. 1 ) then
|
||||
ncrcflag=1
|
||||
else
|
||||
ncrcflag=0
|
||||
endif
|
||||
if( ncrcflag .ne. 1 ) then
|
||||
nbadcrc=nbadcrc+1
|
||||
endif
|
||||
nueflag=0
|
||||
|
||||
! Check the message plus crc against what was sent.
|
||||
do i=1,K
|
||||
nerrmpc=0
|
||||
do i=1,K ! find number of errors in message+crc part of codeword
|
||||
if( msgbits(i) .ne. decoded(i) ) then
|
||||
nueflag=1
|
||||
nerrmpc=nerrmpc+1
|
||||
endif
|
||||
enddo
|
||||
nmpcbad(nerrmpc)=nmpcbad(nerrmpc)+1
|
||||
if( ncrcflag .eq. 1 .and. nueflag .eq. 0 ) then
|
||||
ngood=ngood+1
|
||||
nerrdec(nerr)=nerrdec(nerr)+1
|
||||
@ -211,9 +210,16 @@ do idb = -10, 24
|
||||
enddo
|
||||
|
||||
open(unit=23,file='nerrhisto.dat',status='unknown')
|
||||
do i=1,128
|
||||
do i=1,168
|
||||
write(23,'(i4,2x,i10,i10,f10.2)') i,nerrdec(i),nerrtot(i),real(nerrdec(i))/real(nerrtot(i)+1e-10)
|
||||
enddo
|
||||
close(23)
|
||||
open(unit=25,file='nmpcbad.dat',status='unknown')
|
||||
do i=1,84
|
||||
write(25,'(i4,2x,i10)') i,nmpcbad(i)
|
||||
enddo
|
||||
close(25)
|
||||
|
||||
|
||||
|
||||
end program ldpcsim168
|
||||
|
||||
Loading…
Reference in New Issue
Block a user