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git-svn-id: svn+ssh://svn.code.sf.net/p/wsjt/wsjt/branches/wsjtx@6848 ab8295b8-cf94-4d9e-aec4-7959e3be5d79
124 lines
5.0 KiB
C
124 lines
5.0 KiB
C
// qra64.h
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// Encoding/decoding functions for the QRA64 mode
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//
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// (c) 2016 - Nico Palermo, IV3NWV
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// ------------------------------------------------------------------------------
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// This file is part of the qracodes project, a Forward Error Control
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// encoding/decoding package based on Q-ary RA (Repeat and Accumulate) LDPC codes.
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//
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// qracodes is free software: you can redistribute it and/or modify
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// it under the terms of the GNU General Public License as published by
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// the Free Software Foundation, either version 3 of the License, or
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// (at your option) any later version.
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// qracodes is distributed in the hope that it will be useful,
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// but WITHOUT ANY WARRANTY; without even the implied warranty of
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// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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// GNU General Public License for more details.
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// You should have received a copy of the GNU General Public License
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// along with qracodes source distribution.
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// If not, see <http://www.gnu.org/licenses/>.
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#ifndef _qra64_h_
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#define _qra64_h_
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// qra64_init(...) initialization flags
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#define QRA_NOAP 0 // don't use a-priori knowledge
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#define QRA_AUTOAP 1 // use auto a-priori knowledge
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// QRA code parameters
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#define QRA64_K 12 // information symbols
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#define QRA64_N 63 // codeword length
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#define QRA64_C 51 // (number of parity checks C=(N-K))
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#define QRA64_M 64 // code alphabet size
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#define QRA64_m 6 // bits per symbol
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// packed predefined callsigns and fields as defined in JT65
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#define CALL_CQ 0xFA08319
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#define CALL_QRZ 0xFA0831A
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#define CALL_CQ000 0xFA0831B
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#define CALL_CQ999 0xFA08702
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#define CALL_CQDX 0x5624C39
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#define CALL_DE 0xFF641D1
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#define GRID_BLANK 0x7E91
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typedef struct {
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float decEsNoMetric;
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int apflags;
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int apmycall;
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int apsrccall;
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int apmsg_cqqrz[12]; // [cq/qrz ? blank]
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int apmsg_call1[12]; // [mycall ? blank]
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int apmsg_call1_call2[12]; // [mycall srccall ?]
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int apmask_cqqrz[12];
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int apmask_cqqrz_ooo[12];
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int apmask_call1[12];
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int apmask_call1_ooo[12];
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int apmask_call1_call2[12];
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} qra64codec;
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#ifdef __cplusplus
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extern "C" {
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#endif
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qra64codec *qra64_init(int flags, const int mycall);
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// QRA64 mode initialization function
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// arguments:
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// flags: set the decoder mode
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// When flags = QRA_NOAP no a-priori information will be used by the decoder
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// When flags = QRA_AUTOAP the decoder will attempt to decode with the amount
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// of available a-priori information
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// mycall: 28-bit packed callsign of the user (as computed by JT65)
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// returns:
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// Pointer to the qra64codec data structure allocated and inizialized by the function
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// this handle should be passed to the encoding/decoding functions
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//
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// 0 if unsuccessful (can't allocate memory)
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// -------------------------------------------------------------------------------------------
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void qra64_encode(qra64codec *pcodec, int *y, const int *x);
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// QRA64 mode encoder
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// arguments:
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// pcodec = pointer to a qra64codec data structure as returned by qra64_init
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// x = pointer to the message to encode
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// x must point to an array of integers (i.e. defined as int x[12])
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// y = pointer to the encoded message
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// y must point to an array of integers of lenght 63 (i.e. defined as int y[63])
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// -------------------------------------------------------------------------------------------
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int qra64_decode(qra64codec *pcodec, int *x, const float *r);
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// QRA64 mode decoder
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// arguments:
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// pcodec = pointer to a qra64codec data structure as returned by qra64_init
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// x = pointer to the array of integers where the decoded message will be stored
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// x must point to an array of integers (i.e. defined as int x[12])
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// r = pointer to the received symbols energies (squared amplitudes)
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// r must point to an array of QRA64_M*QRA64_N (=64*63=4032) float numbers.
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// The first QRA_M entries should be the energies of the first symbol in the codeword
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// The last QRA_M entries should be the energies of the last symbol in the codeword
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//
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// return code:
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//
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// The return code is <0 when decoding is unsuccessful
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// -16 indicates that the definition of QRA64_NMSG does not match what required by the code
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// If the decoding process is successfull the return code is accordingly to the following table
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// rc=0 [? ? ?] AP0 (decoding with no a-priori)
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// rc=1 [CQ ? ?] AP27
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// rc=2 [CQ ? ] AP44
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// rc=3 [CALL ? ?] AP29
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// rc=4 [CALL ? ] AP45
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// rc=5 [CALL CALL ?] AP57
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// return codes in the range 1-5 indicate the amount of a-priori information which was required
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// to decode the received message and are possible only when the QRA_AUTOAP mode has been enabled.
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// -------------------------------------------------------------------------------------------
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// encode/decode std msgs in 12 symbols as done in jt65
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void encodemsg_jt65(int *y, const int call1, const int call2, const int grid);
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void decodemsg_jt65(int *call1, int *call2, int *grid, const int *x);
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#ifdef __cplusplus
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}
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#endif
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#endif // _qra64_h_
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