kopia lustrzana https://github.com/M17-Project/M17_Implementations
Wojciech Kaczmarski
rodzic
84eca87cec
commit
7a43152c88
120
SP5WWP/inc/m17.h
120
SP5WWP/inc/m17.h
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@ -1,120 +0,0 @@
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#ifndef M17_CONSTS
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#define M17_CONSTS
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#ifdef __cplusplus
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extern "C" {
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#endif
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#define FLT_LEN 81 //baseband filter length (number of taps)
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#define SW_LEN 80 //syncword detector length
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#define XC_LEN 90 //cross-correlator lookback length in samples
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#define SYM_PER_SWD 8 //symbols per syncword
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#define SYM_PER_PLD 184 //symbols per payload in a frame
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#define SYM_PER_FRA 192 //symbols per whole 40 ms frame
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#define RRC_DEV 7168.0f //.rrc file deviation for +1.0 symbol
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#define XCORR_THRESH 0.90 //arbitrary threshold between 0 and 1
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#define SW_MEAN -0.75 //mean(str_sync)=mean(pkt_sync)
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#define SW_STD 8.21583836f //std(str_sync)*sqrt(length(str_sync)-1)
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#define DIST_THRESH 2.0f //threshold for distance (syncword detection)
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//syncword patterns (RX) TODO:Compute those at runtime from the consts below
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const int8_t lsf_sync[8]={+3, +3, +3, +3, -3, -3, +3, -3};
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const int8_t str_sync[8]={-3, -3, -3, -3, +3, +3, -3, +3};
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const int8_t pkt_sync[8]={+3, -3, +3, +3, -3, -3, -3, -3};
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//symbol levels (RX)
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const float symbs[4]={-3.0, -1.0, +1.0, +3.0};
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//dibits-symbols map (TX)
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const int8_t symbol_map[4]={+1, +3, -1, -3};
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//syncwords
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const uint16_t SYNC_LSF = 0x55F7;
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const uint16_t SYNC_STR = 0xFF5D;
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const uint16_t SYNC_PKT = 0x75FF;
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const uint16_t SYNC_BER = 0xDF55;
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const uint16_t EOT_MRKR = 0x555D;
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//puncturing pattern P_1
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const uint8_t P_1[61]={1,1,0,1,1,1,0,1,1,1,0,1,1,1,0,1,1,
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1,0,1,1,1,0,1,1,1,0,1,1,1,0,1,1,
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1,0,1,1,1,0,1,1,1,0,1,1,1,0,1,1,
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1,0,1,1,1,0,1,1,1,0,1,1};
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//puncturing pattern P_2
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const uint8_t P_2[12]={1,1,1,1,1,1,1,1,1,1,1,0};
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//puncturing pattern P_3
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const uint8_t P_3[8]={1,1,1,1,1,1,1,0};
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//RRC filter - 10 samples per symbol, 8 symbols span
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const float taps[FLT_LEN]=
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{
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-0.003195702904062073f, -0.002930279157647190f, -0.001940667871554463f,
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-0.000356087678023658f, 0.001547011339077758f, 0.003389554791179751f,
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0.004761898604225673f, 0.005310860846138910f, 0.004824746306020221f,
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0.003297923526848786f, 0.000958710871218619f, -0.001749908029791816f,
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-0.004238694106631223f, -0.005881783042101693f, -0.006150256456781309f,
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-0.004745376707651645f, -0.001704189656473565f, 0.002547854551539951f,
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0.007215575568844704f, 0.011231038205363532f, 0.013421952197060707f,
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0.012730475385624438f, 0.008449554307303753f, 0.000436744366018287f,
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-0.010735380379191660f, -0.023726883538258272f, -0.036498030780605324f,
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-0.046500883189991064f, -0.050979050575999614f, -0.047340680079891187f,
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-0.033554880492651755f, -0.008513823955725943f, 0.027696543159614194f,
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0.073664520037517042f, 0.126689053778116234f, 0.182990955139333916f,
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0.238080025892859704f, 0.287235637987091563f, 0.326040247765297220f,
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0.350895727088112619f, 0.359452932027607974f, 0.350895727088112619f,
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0.326040247765297220f, 0.287235637987091563f, 0.238080025892859704f,
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0.182990955139333916f, 0.126689053778116234f, 0.073664520037517042f,
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0.027696543159614194f, -0.008513823955725943f, -0.033554880492651755f,
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-0.047340680079891187f, -0.050979050575999614f, -0.046500883189991064f,
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-0.036498030780605324f, -0.023726883538258272f, -0.010735380379191660f,
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0.000436744366018287f, 0.008449554307303753f, 0.012730475385624438f,
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0.013421952197060707f, 0.011231038205363532f, 0.007215575568844704f,
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0.002547854551539951f, -0.001704189656473565f, -0.004745376707651645f,
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-0.006150256456781309f, -0.005881783042101693f, -0.004238694106631223f,
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-0.001749908029791816f, 0.000958710871218619f, 0.003297923526848786f,
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0.004824746306020221f, 0.005310860846138910f, 0.004761898604225673f,
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0.003389554791179751f, 0.001547011339077758f, -0.000356087678023658f,
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-0.001940667871554463f, -0.002930279157647190f, -0.003195702904062073f
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};
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//randomizing pattern
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const uint8_t rand_seq[46]=
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{
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0xD6, 0xB5, 0xE2, 0x30, 0x82, 0xFF, 0x84, 0x62, 0xBA, 0x4E, 0x96, 0x90, 0xD8, 0x98, 0xDD, 0x5D, 0x0C, 0xC8, 0x52, 0x43, 0x91, 0x1D, 0xF8,
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0x6E, 0x68, 0x2F, 0x35, 0xDA, 0x14, 0xEA, 0xCD, 0x76, 0x19, 0x8D, 0xD5, 0x80, 0xD1, 0x33, 0x87, 0x13, 0x57, 0x18, 0x2D, 0x29, 0x78, 0xC3
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};
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//interleaver pattern
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const uint16_t intrl_seq[368]=
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{
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0, 137, 90, 227, 180, 317, 270, 39, 360, 129, 82, 219, 172, 309, 262, 31,
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352, 121, 74, 211, 164, 301, 254, 23, 344, 113, 66, 203, 156, 293, 246, 15,
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336, 105, 58, 195, 148, 285, 238, 7, 328, 97, 50, 187, 140, 277, 230, 367,
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320, 89, 42, 179, 132, 269, 222, 359, 312, 81, 34, 171, 124, 261, 214, 351,
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304, 73, 26, 163, 116, 253, 206, 343, 296, 65, 18, 155, 108, 245, 198, 335,
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288, 57, 10, 147, 100, 237, 190, 327, 280, 49, 2, 139, 92, 229, 182, 319,
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272, 41, 362, 131, 84, 221, 174, 311, 264, 33, 354, 123, 76, 213, 166, 303,
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256, 25, 346, 115, 68, 205, 158, 295, 248, 17, 338, 107, 60, 197, 150, 287,
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240, 9, 330, 99, 52, 189, 142, 279, 232, 1, 322, 91, 44, 181, 134, 271,
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224, 361, 314, 83, 36, 173, 126, 263, 216, 353, 306, 75, 28, 165, 118, 255,
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208, 345, 298, 67, 20, 157, 110, 247, 200, 337, 290, 59, 12, 149, 102, 239,
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192, 329, 282, 51, 4, 141, 94, 231, 184, 321, 274, 43, 364, 133, 86, 223,
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176, 313, 266, 35, 356, 125, 78, 215, 168, 305, 258, 27, 348, 117, 70, 207,
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160, 297, 250, 19, 340, 109, 62, 199, 152, 289, 242, 11, 332, 101, 54, 191,
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144, 281, 234, 3, 324, 93, 46, 183, 136, 273, 226, 363, 316, 85, 38, 175,
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128, 265, 218, 355, 308, 77, 30, 167, 120, 257, 210, 347, 300, 69, 22, 159,
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112, 249, 202, 339, 292, 61, 14, 151, 104, 241, 194, 331, 284, 53, 6, 143,
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96, 233, 186, 323, 276, 45, 366, 135, 88, 225, 178, 315, 268, 37, 358, 127,
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80, 217, 170, 307, 260, 29, 350, 119, 72, 209, 162, 299, 252, 21, 342, 111,
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64, 201, 154, 291, 244, 13, 334, 103, 56, 193, 146, 283, 236, 5, 326, 95,
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48, 185, 138, 275, 228, 365, 318, 87, 40, 177, 130, 267, 220, 357, 310, 79,
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32, 169, 122, 259, 212, 349, 302, 71, 24, 161, 114, 251, 204, 341, 294, 63,
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16, 153, 106, 243, 196, 333, 286, 55, 8, 145, 98, 235, 188, 325, 278, 47
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};
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#ifdef __cplusplus
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}
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#endif
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#endif
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Plik diff jest za duży
Load Diff
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@ -0,0 +1,131 @@
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//-------------------------------
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// M17 C library - m17lib.h
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//
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// Wojciech Kaczmarski, SP5WWP
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// M17 Project, 28 December 2023
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//-------------------------------
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#ifndef M17_LIB
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#define M17_LIB
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#ifdef __cplusplus
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extern "C" {
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#endif
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#include <inttypes.h>
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#define BSB_SPS 10 //samples per symbol
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#define FLT_SPAN 8 //baseband RRC filter span in symbols
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#define SYM_PER_SWD 8 //symbols per syncword
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#define SW_LEN (BSB_SPS*SYM_PER_SWD) //syncword detector length
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#define SYM_PER_PLD 184 //symbols per payload in a frame
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#define SYM_PER_FRA 192 //symbols per whole 40 ms frame
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#define RRC_DEV 7168.0f //.rrc file deviation for +1.0 symbol
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//L2 metric threshold
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#define DIST_THRESH 2.0f //threshold for distance (syncword detection)
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//Viterbi
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#define K 5 //constraint length
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#define NUM_STATES (1 << (K - 1)) //number of states
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//type declarations
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struct LSF
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{
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uint8_t dst[6];
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uint8_t src[6];
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uint8_t type[2];
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uint8_t meta[112/8];
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uint8_t crc[2];
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};
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//consts
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//syncword patterns (RX) TODO:Compute those at runtime from the consts below
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extern const int8_t lsf_sync[8];
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extern const int8_t str_sync[8];
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extern const int8_t pkt_sync[8];
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//symbol levels (RX)
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extern const float symbs[4];
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//dibits-symbols map (TX)
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extern const int8_t symbol_map[4];
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//syncwords
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extern const uint16_t SYNC_LSF;
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extern const uint16_t SYNC_STR;
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extern const uint16_t SYNC_PKT;
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extern const uint16_t SYNC_BER;
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extern const uint16_t EOT_MRKR;
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//puncturing pattern P_1
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extern const uint8_t P_1[61];
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//puncturing pattern P_2
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extern const uint8_t P_2[12];
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//puncturing pattern P_3
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extern const uint8_t P_3[8];
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//M17 CRC polynomial
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extern const uint16_t M17_CRC_POLY;
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//sample RRC filter for 48kHz sample rate
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//alpha=0.5, span=8, sps=10, gain=sqrt(sps)
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extern const float taps_10[8*10+1];
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//sample RRC filter for 24kHz sample rate
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//alpha=0.5, span=8, sps=5, gain=sqrt(sps)
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extern const float taps_5[8*5+1];
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//Golay coding
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extern const uint16_t encode_matrix[12];
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extern const uint16_t decode_matrix[12];
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//randomizing pattern
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extern const uint8_t rand_seq[46];
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//interleaver pattern
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extern const uint16_t intrl_seq[368];
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//functions
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uint16_t CRC_M17(const uint8_t *in, const uint16_t len);
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uint32_t golay24_encode(const uint16_t data);
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void int_to_soft(uint16_t* out, const uint16_t in, uint8_t len);
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uint16_t soft_to_int(const uint16_t* in, uint8_t len);
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uint16_t div16(uint16_t a, uint16_t b);
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uint16_t mul16(uint16_t a, uint16_t b);
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uint16_t soft_bit_XOR(const uint16_t a, const uint16_t b);
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void soft_XOR(uint16_t* out, const uint16_t* a, const uint16_t* b, uint8_t len);
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uint32_t s_popcount(const uint16_t* in, uint8_t siz);
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void s_calc_checksum(uint16_t* out, const uint16_t* value);
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uint32_t s_detect_errors(const uint16_t* codeword);
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uint16_t golay24_sdecode(const uint16_t* codeword);
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uint32_t viterbi_decode(uint8_t* out, const uint16_t* in, uint16_t len);
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uint32_t viterbi_decode_punctured(uint8_t* out, const uint16_t* in, const uint8_t* punct, const uint16_t in_len, const uint16_t p_len);
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void viterbi_decode_bit(uint16_t s0, uint16_t s1, size_t pos);
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uint32_t viterbi_chainback(uint8_t* out, size_t pos, uint16_t len);
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uint16_t q_abs_diff(const uint16_t v1, const uint16_t v2);
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void viterbi_reset(void);
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void send_preamble(const uint8_t type);
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void send_syncword(const uint16_t syncword);
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void send_data(const uint8_t* in);
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void send_eot(void);
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void conv_encode_stream_frame(uint8_t* out, const uint8_t* in, const uint16_t fn);
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void conv_encode_packet_frame(uint8_t* out, uint8_t* in);
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void conv_encode_LSF(uint8_t* out, const struct LSF *in);
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uint16_t LSF_CRC(const struct LSF *in);
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void decode_callsign_bytes(uint8_t *outp, const uint8_t *inp);
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void decode_callsign_value(uint8_t *outp, const uint64_t inp);
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uint8_t encode_callsign(uint64_t* out, const uint8_t* inp);
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void decode_LICH(uint8_t* outp, const uint16_t* inp);
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float eucl_norm(const float* in1, const int8_t* in2, uint8_t len);
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#ifdef __cplusplus
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}
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#endif
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#endif
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@ -1,5 +1,5 @@
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m17-coder-sym: m17-coder-sym.c golay.c golay.h crc.c crc.h ../inc/m17.h
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gcc -O2 -Wall m17-coder-sym.c golay.c crc.c -o m17-coder-sym -lm
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m17-coder-sym: m17-coder-sym.c ../lib/m17lib.c ../lib/m17lib.h
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gcc -O2 -Wall m17-coder-sym.c ../lib/m17lib.c -o m17-coder-sym -lm
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clean:
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rm -f m17-coder-sym
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@ -1,23 +0,0 @@
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#include <string.h>
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#include <stdint.h>
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#include "crc.h"
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const uint16_t M17_CRC_POLY = 0x5935;
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uint16_t CRC_M17(const uint8_t *in, const uint16_t len)
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{
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uint32_t crc=0xFFFF; //init val
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for(uint16_t i=0; i<len; i++)
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{
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crc^=in[i]<<8;
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for(uint8_t j=0; j<8; j++)
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{
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crc<<=1;
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if(crc&0x10000)
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crc=(crc^M17_CRC_POLY)&0xFFFF;
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}
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}
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return crc&(0xFFFF);
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}
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@ -1,12 +0,0 @@
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#ifndef CRC_H
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#define CRC_H
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#ifdef __cplusplus
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extern "C" {
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#endif
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uint16_t CRC_M17(const uint8_t *in, const uint16_t len);
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#ifdef __cplusplus
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}
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#endif
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#endif
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@ -1,24 +0,0 @@
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#include <string.h>
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#include <stdint.h>
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#include "golay.h"
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static const uint16_t encode_matrix[12]=
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{
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0x8eb, 0x93e, 0xa97, 0xdc6, 0x367, 0x6cd,
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0xd99, 0x3da, 0x7b4, 0xf68, 0x63b, 0xc75
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};
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uint32_t golay24_encode(const uint16_t data)
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{
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uint16_t checksum=0;
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for(uint8_t i=0; i<12; i++)
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{
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if(data&(1<<i))
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{
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checksum ^= encode_matrix[i];
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}
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}
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return (data<<12) | checksum;
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}
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@ -1,12 +0,0 @@
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#ifndef GOLAY_H
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#define GOLAY_H
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#ifdef __cplusplus
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extern "C" {
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#endif
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uint32_t golay24_encode(const uint16_t data);
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#ifdef __cplusplus
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}
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#endif
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#endif
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@ -2,20 +2,11 @@
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#include <string.h>
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#include <stdint.h>
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#include "../inc/m17.h"
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#include "golay.h"
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#include "crc.h"
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#include "../lib/m17lib.h"
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//#define FN60_DEBUG
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struct LSF
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{
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uint8_t dst[6];
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uint8_t src[6];
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uint8_t type[2];
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uint8_t meta[112/8];
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uint8_t crc[2];
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} lsf, next_lsf;
|
||||
struct LSF lsf, next_lsf;
|
||||
|
||||
uint8_t lich[6]; //48 bits packed raw, unencoded LICH
|
||||
uint8_t lich_encoded[12]; //96 bits packed, encoded LICH
|
||||
|
|
@ -28,228 +19,6 @@ uint8_t lich_cnt=0; //0..5 LICH counter
|
|||
uint8_t got_lsf=0; //have we filled the LSF struct yet?
|
||||
uint8_t finished=0;
|
||||
|
||||
void send_Preamble(const uint8_t type)
|
||||
{
|
||||
float symb;
|
||||
|
||||
if(type) //pre-BERT
|
||||
{
|
||||
for(uint16_t i=0; i<192/2; i++) //40ms * 4800 = 192
|
||||
{
|
||||
symb=-3.0;
|
||||
fwrite((uint8_t*)&symb, sizeof(float), 1, stdout);
|
||||
symb=+3.0;
|
||||
fwrite((uint8_t*)&symb, sizeof(float), 1, stdout);
|
||||
}
|
||||
}
|
||||
else //pre-LSF
|
||||
{
|
||||
for(uint16_t i=0; i<192/2; i++) //40ms * 4800 = 192
|
||||
{
|
||||
symb=+3.0;
|
||||
fwrite((uint8_t*)&symb, sizeof(float), 1, stdout);
|
||||
symb=-3.0;
|
||||
fwrite((uint8_t*)&symb, sizeof(float), 1, stdout);
|
||||
}
|
||||
}
|
||||
}
|
||||
|
||||
void send_Syncword(const uint16_t sword)
|
||||
{
|
||||
float symb;
|
||||
|
||||
for(uint8_t i=0; i<16; i+=2)
|
||||
{
|
||||
symb=symbol_map[(sword>>(14-i))&3];
|
||||
fwrite((uint8_t*)&symb, sizeof(float), 1, stdout);
|
||||
}
|
||||
}
|
||||
|
||||
//send the data (can be used for both LSF and frames)
|
||||
void send_data(uint8_t* in)
|
||||
{
|
||||
float s=0.0;
|
||||
for(uint16_t i=0; i<SYM_PER_PLD; i++) //40ms * 4800 - 8 (syncword)
|
||||
{
|
||||
s=symbol_map[in[2*i]*2+in[2*i+1]];
|
||||
fwrite((uint8_t*)&s, sizeof(float), 1, stdout);
|
||||
}
|
||||
}
|
||||
|
||||
void send_EoT()
|
||||
{
|
||||
float symb=+3.0;
|
||||
for(uint16_t i=0; i<192; i++) //40ms * 4800 = 192
|
||||
{
|
||||
fwrite((uint8_t*)&symb, sizeof(float), 1, stdout);
|
||||
}
|
||||
}
|
||||
|
||||
//out - unpacked bits
|
||||
//in - packed raw bits
|
||||
//fn - frame number
|
||||
void conv_Encode_Frame(uint8_t* out, uint8_t* in, uint16_t fn)
|
||||
{
|
||||
uint8_t pp_len = sizeof(P_2);
|
||||
uint8_t p=0; //puncturing pattern index
|
||||
uint16_t pb=0; //pushed punctured bits
|
||||
uint8_t ud[144+4+4]; //unpacked data
|
||||
|
||||
memset(ud, 0, 144+4+4);
|
||||
|
||||
//unpack frame number
|
||||
for(uint8_t i=0; i<16; i++)
|
||||
{
|
||||
ud[4+i]=(fn>>(15-i))&1;
|
||||
}
|
||||
|
||||
//unpack data
|
||||
for(uint8_t i=0; i<16; i++)
|
||||
{
|
||||
for(uint8_t j=0; j<8; j++)
|
||||
{
|
||||
ud[4+16+i*8+j]=(in[i]>>(7-j))&1;
|
||||
}
|
||||
}
|
||||
|
||||
//encode
|
||||
for(uint8_t i=0; i<144+4; i++)
|
||||
{
|
||||
uint8_t G1=(ud[i+4] +ud[i+1]+ud[i+0])%2;
|
||||
uint8_t G2=(ud[i+4]+ud[i+3]+ud[i+2] +ud[i+0])%2;
|
||||
|
||||
//printf("%d%d", G1, G2);
|
||||
|
||||
if(P_2[p])
|
||||
{
|
||||
out[pb]=G1;
|
||||
pb++;
|
||||
}
|
||||
|
||||
p++;
|
||||
p%=pp_len;
|
||||
|
||||
if(P_2[p])
|
||||
{
|
||||
out[pb]=G2;
|
||||
pb++;
|
||||
}
|
||||
|
||||
p++;
|
||||
p%=pp_len;
|
||||
}
|
||||
|
||||
//printf("pb=%d\n", pb);
|
||||
}
|
||||
|
||||
//out - unpacked bits
|
||||
//in - packed raw bits (LSF struct)
|
||||
void conv_Encode_LSF(uint8_t* out, struct LSF *in)
|
||||
{
|
||||
uint8_t pp_len = sizeof(P_1);
|
||||
uint8_t p=0; //puncturing pattern index
|
||||
uint16_t pb=0; //pushed punctured bits
|
||||
uint8_t ud[240+4+4]; //unpacked data
|
||||
|
||||
memset(ud, 0, 240+4+4);
|
||||
|
||||
//unpack DST
|
||||
for(uint8_t i=0; i<8; i++)
|
||||
{
|
||||
ud[4+i] =((in->dst[0])>>(7-i))&1;
|
||||
ud[4+i+8] =((in->dst[1])>>(7-i))&1;
|
||||
ud[4+i+16]=((in->dst[2])>>(7-i))&1;
|
||||
ud[4+i+24]=((in->dst[3])>>(7-i))&1;
|
||||
ud[4+i+32]=((in->dst[4])>>(7-i))&1;
|
||||
ud[4+i+40]=((in->dst[5])>>(7-i))&1;
|
||||
}
|
||||
|
||||
//unpack SRC
|
||||
for(uint8_t i=0; i<8; i++)
|
||||
{
|
||||
ud[4+i+48]=((in->src[0])>>(7-i))&1;
|
||||
ud[4+i+56]=((in->src[1])>>(7-i))&1;
|
||||
ud[4+i+64]=((in->src[2])>>(7-i))&1;
|
||||
ud[4+i+72]=((in->src[3])>>(7-i))&1;
|
||||
ud[4+i+80]=((in->src[4])>>(7-i))&1;
|
||||
ud[4+i+88]=((in->src[5])>>(7-i))&1;
|
||||
}
|
||||
|
||||
//unpack TYPE
|
||||
for(uint8_t i=0; i<8; i++)
|
||||
{
|
||||
ud[4+i+96] =((in->type[0])>>(7-i))&1;
|
||||
ud[4+i+104]=((in->type[1])>>(7-i))&1;
|
||||
}
|
||||
|
||||
//unpack META
|
||||
for(uint8_t i=0; i<8; i++)
|
||||
{
|
||||
ud[4+i+112]=((in->meta[0])>>(7-i))&1;
|
||||
ud[4+i+120]=((in->meta[1])>>(7-i))&1;
|
||||
ud[4+i+128]=((in->meta[2])>>(7-i))&1;
|
||||
ud[4+i+136]=((in->meta[3])>>(7-i))&1;
|
||||
ud[4+i+144]=((in->meta[4])>>(7-i))&1;
|
||||
ud[4+i+152]=((in->meta[5])>>(7-i))&1;
|
||||
ud[4+i+160]=((in->meta[6])>>(7-i))&1;
|
||||
ud[4+i+168]=((in->meta[7])>>(7-i))&1;
|
||||
ud[4+i+176]=((in->meta[8])>>(7-i))&1;
|
||||
ud[4+i+184]=((in->meta[9])>>(7-i))&1;
|
||||
ud[4+i+192]=((in->meta[10])>>(7-i))&1;
|
||||
ud[4+i+200]=((in->meta[11])>>(7-i))&1;
|
||||
ud[4+i+208]=((in->meta[12])>>(7-i))&1;
|
||||
ud[4+i+216]=((in->meta[13])>>(7-i))&1;
|
||||
}
|
||||
|
||||
//unpack CRC
|
||||
for(uint8_t i=0; i<8; i++)
|
||||
{
|
||||
ud[4+i+224]=((in->crc[0])>>(7-i))&1;
|
||||
ud[4+i+232]=((in->crc[1])>>(7-i))&1;
|
||||
}
|
||||
|
||||
//encode
|
||||
for(uint8_t i=0; i<240+4; i++)
|
||||
{
|
||||
uint8_t G1=(ud[i+4] +ud[i+1]+ud[i+0])%2;
|
||||
uint8_t G2=(ud[i+4]+ud[i+3]+ud[i+2] +ud[i+0])%2;
|
||||
|
||||
//printf("%d%d", G1, G2);
|
||||
|
||||
if(P_1[p])
|
||||
{
|
||||
out[pb]=G1;
|
||||
pb++;
|
||||
}
|
||||
|
||||
p++;
|
||||
p%=pp_len;
|
||||
|
||||
if(P_1[p])
|
||||
{
|
||||
out[pb]=G2;
|
||||
pb++;
|
||||
}
|
||||
|
||||
p++;
|
||||
p%=pp_len;
|
||||
}
|
||||
|
||||
//printf("pb=%d\n", pb);
|
||||
}
|
||||
|
||||
uint16_t LSF_CRC(struct LSF *in)
|
||||
{
|
||||
uint8_t d[28];
|
||||
|
||||
memcpy(&d[0], in->dst, 6);
|
||||
memcpy(&d[6], in->src, 6);
|
||||
memcpy(&d[12], in->type, 2);
|
||||
memcpy(&d[14], in->meta, 14);
|
||||
|
||||
return CRC_M17(d, 28);
|
||||
}
|
||||
|
||||
//main routine
|
||||
int main(void)
|
||||
{
|
||||
|
|
@ -288,7 +57,7 @@ int main(void)
|
|||
if(got_lsf) //stream frames
|
||||
{
|
||||
//send stream frame syncword
|
||||
send_Syncword(SYNC_STR);
|
||||
send_syncword(SYNC_STR);
|
||||
|
||||
//extract LICH from the whole LSF
|
||||
switch(lich_cnt)
|
||||
|
|
@ -376,7 +145,7 @@ int main(void)
|
|||
}
|
||||
|
||||
//encode the rest of the frame
|
||||
conv_Encode_Frame(&enc_bits[96], data, finished ? (fn | 0x8000) : fn);
|
||||
conv_encode_stream_frame(&enc_bits[96], data, finished ? (fn | 0x8000) : fn);
|
||||
|
||||
//reorder bits
|
||||
for(uint16_t i=0; i<SYM_PER_PLD*2; i++)
|
||||
|
|
@ -424,13 +193,13 @@ int main(void)
|
|||
got_lsf=1;
|
||||
|
||||
//encode LSF data
|
||||
conv_Encode_LSF(enc_bits, &lsf);
|
||||
conv_encode_LSF(enc_bits, &lsf);
|
||||
|
||||
//send out the preamble and LSF
|
||||
send_Preamble(0); //0 - LSF preamble, as opposed to 1 - BERT preamble
|
||||
send_preamble(0); //0 - LSF preamble, as opposed to 1 - BERT preamble
|
||||
|
||||
//send LSF syncword
|
||||
send_Syncword(SYNC_LSF);
|
||||
send_syncword(SYNC_LSF);
|
||||
|
||||
//reorder bits
|
||||
for(uint16_t i=0; i<SYM_PER_PLD*2; i++)
|
||||
|
|
@ -474,8 +243,8 @@ int main(void)
|
|||
printf("\n");*/
|
||||
}
|
||||
|
||||
if (finished)
|
||||
send_EoT();
|
||||
if(finished)
|
||||
send_eot();
|
||||
}
|
||||
|
||||
return 0;
|
||||
|
|
|
|||
|
|
@ -1,5 +1,5 @@
|
|||
m17-decoder-sym: m17-decoder-sym.c golay.c golay.h viterbi.c viterbi.h crc.c crc.h ../inc/m17.h
|
||||
gcc -Wall -O2 m17-decoder-sym.c golay.c viterbi.c crc.c -o m17-decoder-sym -lm
|
||||
m17-decoder-sym: m17-decoder-sym.c ../lib/m17lib.c ../lib/m17lib.h
|
||||
gcc -Wall -O2 m17-decoder-sym.c ../lib/m17lib.c -o m17-decoder-sym -lm
|
||||
|
||||
clean:
|
||||
rm -f m17-decoder-sym
|
||||
|
|
|
|||
|
|
@ -1,23 +0,0 @@
|
|||
#include <string.h>
|
||||
#include <stdint.h>
|
||||
#include "crc.h"
|
||||
|
||||
const uint16_t M17_CRC_POLY = 0x5935;
|
||||
|
||||
uint16_t CRC_M17(const uint8_t *in, const uint16_t len)
|
||||
{
|
||||
uint32_t crc=0xFFFF; //init val
|
||||
|
||||
for(uint16_t i=0; i<len; i++)
|
||||
{
|
||||
crc^=in[i]<<8;
|
||||
for(uint8_t j=0; j<8; j++)
|
||||
{
|
||||
crc<<=1;
|
||||
if(crc&0x10000)
|
||||
crc=(crc^M17_CRC_POLY)&0xFFFF;
|
||||
}
|
||||
}
|
||||
|
||||
return crc&(0xFFFF);
|
||||
}
|
||||
|
|
@ -1,12 +0,0 @@
|
|||
#ifndef CRC_H
|
||||
#define CRC_H
|
||||
|
||||
#ifdef __cplusplus
|
||||
extern "C" {
|
||||
#endif
|
||||
uint16_t CRC_M17(const uint8_t *in, const uint16_t len);
|
||||
#ifdef __cplusplus
|
||||
}
|
||||
#endif
|
||||
|
||||
#endif
|
||||
|
|
@ -1,228 +0,0 @@
|
|||
#include <string.h>
|
||||
#include <stdint.h>
|
||||
#include "golay.h"
|
||||
|
||||
static const uint16_t encode_matrix[12]=
|
||||
{
|
||||
0x8eb, 0x93e, 0xa97, 0xdc6, 0x367, 0x6cd,
|
||||
0xd99, 0x3da, 0x7b4, 0xf68, 0x63b, 0xc75
|
||||
};
|
||||
|
||||
const uint16_t decode_matrix[12]=
|
||||
{
|
||||
0xc75, 0x49f, 0x93e, 0x6e3, 0xdc6, 0xf13,
|
||||
0xab9, 0x1ed, 0x3da, 0x7b4, 0xf68, 0xa4f
|
||||
};
|
||||
|
||||
//0 index - LSB
|
||||
void IntToSoft(uint16_t* out, const uint16_t in, uint8_t len)
|
||||
{
|
||||
for(uint8_t i=0; i<len; i++)
|
||||
{
|
||||
(in>>i)&1 ? (out[i]=0xFFFF) : (out[i]=0);
|
||||
}
|
||||
}
|
||||
|
||||
uint16_t SoftToInt(const uint16_t* in, uint8_t len)
|
||||
{
|
||||
uint16_t tmp=0;
|
||||
|
||||
for(uint8_t i=0; i<len; i++)
|
||||
{
|
||||
if(in[i]>0x7FFF)
|
||||
tmp|=(1<<i);
|
||||
}
|
||||
|
||||
return tmp;
|
||||
}
|
||||
|
||||
//Quadrant I fixed point division with saturation
|
||||
//result=a/b
|
||||
uint16_t Div16(uint16_t a, uint16_t b)
|
||||
{
|
||||
uint32_t aa=(uint32_t)a<<16;
|
||||
uint32_t r=aa/b;
|
||||
|
||||
if(r<=0xFFFF)
|
||||
return r;
|
||||
else
|
||||
return 0xFFFF;
|
||||
}
|
||||
|
||||
//Quadrant I fixed point multiplication
|
||||
//result=a/b
|
||||
uint16_t Mul16(uint16_t a, uint16_t b)
|
||||
{
|
||||
return (uint16_t)(((uint32_t)a*b)>>16);
|
||||
}
|
||||
|
||||
//use bilinear interpolation for XOR
|
||||
uint16_t SoftBitXOR(const uint16_t a, const uint16_t b)
|
||||
{
|
||||
return Mul16(Div16(0xFFFF-b, 0xFFFF), Div16(a, 0xFFFF)) + Mul16(Div16(b, 0xFFFF), Div16(0xFFFF-a, 0xFFFF));
|
||||
}
|
||||
|
||||
//soft XOR
|
||||
void SoftXOR(uint16_t* out, const uint16_t* a, const uint16_t* b, uint8_t len)
|
||||
{
|
||||
for(uint8_t i=0; i<len; i++)
|
||||
out[i]=SoftBitXOR(a[i], b[i]);
|
||||
}
|
||||
|
||||
//soft equivalent of popcount
|
||||
uint32_t spopcount(const uint16_t* in, uint8_t siz)
|
||||
{
|
||||
uint32_t tmp=0;
|
||||
|
||||
for(uint8_t i=0; i<siz; i++)
|
||||
tmp+=in[i];
|
||||
|
||||
return tmp;
|
||||
}
|
||||
|
||||
void calcChecksumS(uint16_t* out, const uint16_t* value)
|
||||
{
|
||||
uint16_t checksum[12];
|
||||
uint16_t soft_em[12]; //soft valued encoded matrix entry
|
||||
|
||||
for(uint8_t i=0; i<12; i++)
|
||||
checksum[i]=0;
|
||||
|
||||
for(uint8_t i=0; i<12; i++)
|
||||
{
|
||||
IntToSoft(soft_em, encode_matrix[i], 12);
|
||||
|
||||
if(value[i]>0x7FFF)
|
||||
{
|
||||
SoftXOR(checksum, checksum, soft_em, 12);
|
||||
}
|
||||
}
|
||||
|
||||
memcpy((uint8_t*)out, (uint8_t*)checksum, 12*2);
|
||||
}
|
||||
|
||||
uint32_t SdetectErrors(const uint16_t* codeword)
|
||||
{
|
||||
uint16_t data[12];
|
||||
uint16_t parity[12];
|
||||
uint16_t cksum[12];
|
||||
uint16_t syndrome[12];
|
||||
uint32_t weight; //for soft popcount
|
||||
|
||||
memcpy((uint8_t*)data, (uint8_t*)&codeword[12], 2*12);
|
||||
memcpy((uint8_t*)parity, (uint8_t*)&codeword[0], 2*12);
|
||||
|
||||
calcChecksumS(cksum, data);
|
||||
SoftXOR(syndrome, parity, cksum, 12);
|
||||
|
||||
weight=spopcount(syndrome, 12);
|
||||
|
||||
//all (less than 4) errors in the parity part
|
||||
if(weight < 4*0xFFFE)
|
||||
{
|
||||
//printf("1: %1.2f\n", (float)weight/0xFFFF);
|
||||
return SoftToInt(syndrome, 12);
|
||||
}
|
||||
|
||||
//one of the errors in data part, up to 3 in parity
|
||||
for(uint8_t i = 0; i<12; i++)
|
||||
{
|
||||
uint16_t e = 1<<i;
|
||||
uint16_t coded_error = encode_matrix[i];
|
||||
uint16_t scoded_error[12]; //soft coded_error
|
||||
uint16_t sc[12]; //syndrome^coded_error
|
||||
|
||||
IntToSoft(scoded_error, coded_error, 12);
|
||||
SoftXOR(sc, syndrome, scoded_error, 12);
|
||||
weight=spopcount(sc, 12);
|
||||
|
||||
if(weight < 3*0xFFFE)
|
||||
{
|
||||
//printf("2: %1.2f\n", (float)weight/0xFFFF+1);
|
||||
uint16_t s=SoftToInt(syndrome, 12);
|
||||
return (e << 12) | (s ^ coded_error);
|
||||
}
|
||||
}
|
||||
|
||||
//two of the errors in data part and up to 2 in parity
|
||||
for(uint8_t i = 0; i<11; i++)
|
||||
{
|
||||
for(uint8_t j = i+1; j<12; j++)
|
||||
{
|
||||
uint16_t e = (1<<i) | (1<<j);
|
||||
uint16_t coded_error = encode_matrix[i]^encode_matrix[j];
|
||||
uint16_t scoded_error[12]; //soft coded_error
|
||||
uint16_t sc[12]; //syndrome^coded_error
|
||||
|
||||
IntToSoft(scoded_error, coded_error, 12);
|
||||
SoftXOR(sc, syndrome, scoded_error, 12);
|
||||
weight=spopcount(sc, 12);
|
||||
|
||||
if(weight < 2*0xFFFF)
|
||||
{
|
||||
//printf("3: %1.2f\n", (float)weight/0xFFFF+2);
|
||||
uint16_t s=SoftToInt(syndrome, 12);
|
||||
return (e << 12) | (s ^ coded_error);
|
||||
}
|
||||
}
|
||||
}
|
||||
|
||||
//algebraic decoding magic
|
||||
uint16_t inv_syndrome[12]={0,0,0,0,0,0,0,0,0,0,0,0};
|
||||
uint16_t dm[12]; //soft decode matrix
|
||||
|
||||
for(uint8_t i=0; i<12; i++)
|
||||
{
|
||||
if(syndrome[i] > 0x7FFF)
|
||||
{
|
||||
IntToSoft(dm, decode_matrix[i], 12);
|
||||
SoftXOR(inv_syndrome, inv_syndrome, dm, 12);
|
||||
}
|
||||
}
|
||||
|
||||
//all (less than 4) errors in the data part
|
||||
weight=spopcount(inv_syndrome, 12);
|
||||
if(weight < 4*0xFFFF)
|
||||
{
|
||||
//printf("4: %1.2f\n", (float)weight/0xFFFF);
|
||||
return SoftToInt(inv_syndrome, 12) << 12;
|
||||
}
|
||||
|
||||
//one error in parity bits, up to 3 in data - this part has some quirks, the reason remains unknown
|
||||
for(uint8_t i=0; i<12; i++)
|
||||
{
|
||||
uint16_t e = 1<<i;
|
||||
uint16_t coding_error = decode_matrix[i];
|
||||
|
||||
uint16_t ce[12]; //soft coding error
|
||||
uint16_t tmp[12];
|
||||
|
||||
IntToSoft(ce, coding_error, 12);
|
||||
SoftXOR(tmp, inv_syndrome, ce, 12);
|
||||
weight=spopcount(tmp, 12);
|
||||
|
||||
if(weight < 3*(0xFFFF+2))
|
||||
{
|
||||
//printf("5: %1.2f\n", (float)weight/0xFFFF+1);
|
||||
return ((SoftToInt(inv_syndrome, 12) ^ coding_error) << 12) | e;
|
||||
}
|
||||
}
|
||||
|
||||
return 0xFFFFFFFF;
|
||||
}
|
||||
|
||||
//soft decode
|
||||
uint16_t golay24_sdecode(const uint16_t* codeword)
|
||||
{
|
||||
//match the bit order in M17
|
||||
uint16_t cw[24];
|
||||
for(uint8_t i=0; i<24; i++)
|
||||
cw[i]=codeword[23-i];
|
||||
|
||||
uint32_t errors = SdetectErrors(cw);
|
||||
|
||||
if(errors == 0xFFFFFFFF)
|
||||
return 0xFFFF;
|
||||
|
||||
return (((SoftToInt(&cw[0], 16) | (SoftToInt(&cw[16], 8) << 16)) ^ errors) >> 12) & 0x0FFF;
|
||||
}
|
||||
|
|
@ -1,21 +0,0 @@
|
|||
#ifndef GOLAY_H
|
||||
#define GOLAY_H
|
||||
|
||||
#ifdef __cplusplus
|
||||
extern "C" {
|
||||
#endif
|
||||
void IntToSoft(uint16_t* out, const uint16_t in, uint8_t len);
|
||||
uint16_t SoftToInt(const uint16_t* in, uint8_t len);
|
||||
uint16_t Div16(uint16_t a, uint16_t b);
|
||||
uint16_t Mul16(uint16_t a, uint16_t b);
|
||||
uint16_t SoftBitXOR(const uint16_t a, const uint16_t b);
|
||||
void SoftXOR(uint16_t* out, const uint16_t* a, const uint16_t* b, uint8_t len);
|
||||
uint32_t spopcount(const uint16_t* in, uint8_t siz);
|
||||
void calcChecksumS(uint16_t* out, const uint16_t* value);
|
||||
uint32_t SdetectErrors(const uint16_t* codeword);
|
||||
uint16_t golay24_sdecode(const uint16_t* codeword);
|
||||
#ifdef __cplusplus
|
||||
}
|
||||
#endif
|
||||
|
||||
#endif
|
||||
|
|
@ -2,12 +2,8 @@
|
|||
#include <stdlib.h>
|
||||
#include <stdint.h>
|
||||
#include <string.h>
|
||||
#include <math.h>
|
||||
|
||||
#include "../inc/m17.h"
|
||||
#include "golay.h"
|
||||
#include "viterbi.h"
|
||||
#include "crc.h"
|
||||
#include "../lib/m17lib.h"
|
||||
|
||||
#define DECODE_CALLSIGNS
|
||||
#define SHOW_VITERBI_ERRS
|
||||
|
|
@ -33,76 +29,6 @@ uint8_t syncd=0; //syncword found?
|
|||
uint8_t fl=0; //Frame=0 of LSF=1
|
||||
uint8_t pushed; //counter for pushed symbols
|
||||
|
||||
//soft decodes LICH into a 6-byte array
|
||||
//input - soft bits
|
||||
//output - an array of packed bits
|
||||
void decode_LICH(uint8_t* outp, const uint16_t* inp)
|
||||
{
|
||||
uint16_t tmp;
|
||||
|
||||
memset(outp, 0, 5);
|
||||
|
||||
tmp=golay24_sdecode(&inp[0]);
|
||||
outp[0]=(tmp>>4)&0xFF;
|
||||
outp[1]|=(tmp&0xF)<<4;
|
||||
tmp=golay24_sdecode(&inp[1*24]);
|
||||
outp[1]|=(tmp>>8)&0xF;
|
||||
outp[2]=tmp&0xFF;
|
||||
tmp=golay24_sdecode(&inp[2*24]);
|
||||
outp[3]=(tmp>>4)&0xFF;
|
||||
outp[4]|=(tmp&0xF)<<4;
|
||||
tmp=golay24_sdecode(&inp[3*24]);
|
||||
outp[4]|=(tmp>>8)&0xF;
|
||||
outp[5]=tmp&0xFF;
|
||||
}
|
||||
|
||||
//decodes a 6-byte long array to a callsign
|
||||
void decode_callsign(uint8_t *outp, const uint8_t *inp)
|
||||
{
|
||||
uint64_t encoded=0;
|
||||
|
||||
//repack the data to a uint64_t
|
||||
for(uint8_t i=0; i<6; i++)
|
||||
encoded|=(uint64_t)inp[5-i]<<(8*i);
|
||||
|
||||
//check if the value is reserved (not a callsign)
|
||||
if(encoded>=262144000000000ULL)
|
||||
{
|
||||
if(encoded==0xFFFFFFFFFFFF) //broadcast
|
||||
{
|
||||
sprintf((char*)outp, "#BCAST");
|
||||
}
|
||||
else
|
||||
{
|
||||
outp[0]=0;
|
||||
}
|
||||
|
||||
return;
|
||||
}
|
||||
|
||||
//decode the callsign
|
||||
uint8_t i=0;
|
||||
while(encoded>0)
|
||||
{
|
||||
outp[i]=" ABCDEFGHIJKLMNOPQRSTUVWXYZ0123456789-/."[encoded%40];
|
||||
encoded/=40;
|
||||
i++;
|
||||
}
|
||||
outp[i]=0;
|
||||
}
|
||||
|
||||
float eucl_norm(const float* in1, const int8_t* in2, uint8_t len)
|
||||
{
|
||||
float tmp = 0.0f;
|
||||
|
||||
for(uint8_t i=0; i<len; i++)
|
||||
{
|
||||
tmp += powf(in1[i]-(float)in2[i], 2.0f);
|
||||
}
|
||||
|
||||
return sqrt(tmp);
|
||||
}
|
||||
|
||||
int main(void)
|
||||
{
|
||||
while(1)
|
||||
|
|
@ -214,7 +140,7 @@ int main(void)
|
|||
}
|
||||
|
||||
//decode
|
||||
uint32_t e=decodePunctured(frame_data, enc_data, P_2, 272, 12);
|
||||
uint32_t e=viterbi_decode_punctured(frame_data, enc_data, P_2, 272, 12);
|
||||
|
||||
uint16_t fn = (frame_data[1] << 8) | frame_data[2];
|
||||
|
||||
|
|
@ -256,8 +182,8 @@ int main(void)
|
|||
#ifdef DECODE_CALLSIGNS
|
||||
uint8_t d_dst[12], d_src[12]; //decoded strings
|
||||
|
||||
decode_callsign(d_dst, &lsf[0]);
|
||||
decode_callsign(d_src, &lsf[6]);
|
||||
decode_callsign_bytes(d_dst, &lsf[0]);
|
||||
decode_callsign_bytes(d_src, &lsf[6]);
|
||||
|
||||
//DST
|
||||
printf("DST: %-9s ", d_dst);
|
||||
|
|
@ -308,7 +234,7 @@ int main(void)
|
|||
printf("LSF\n");
|
||||
|
||||
//decode
|
||||
uint32_t e=decodePunctured(lsf, d_soft_bit, P_1, 2*SYM_PER_PLD, 61);
|
||||
uint32_t e=viterbi_decode_punctured(lsf, d_soft_bit, P_1, 2*SYM_PER_PLD, 61);
|
||||
|
||||
//shift the buffer 1 position left - get rid of the encoded flushing bits
|
||||
for(uint8_t i=0; i<30; i++)
|
||||
|
|
@ -318,8 +244,8 @@ int main(void)
|
|||
#ifdef DECODE_CALLSIGNS
|
||||
uint8_t d_dst[12], d_src[12]; //decoded strings
|
||||
|
||||
decode_callsign(d_dst, &lsf[0]);
|
||||
decode_callsign(d_src, &lsf[6]);
|
||||
decode_callsign_bytes(d_dst, &lsf[0]);
|
||||
decode_callsign_bytes(d_src, &lsf[6]);
|
||||
|
||||
//DST
|
||||
printf("DST: %-9s ", d_dst);
|
||||
|
|
|
|||
|
|
@ -1,69 +0,0 @@
|
|||
#include <stdio.h>
|
||||
#include <stdlib.h>
|
||||
#include <stdint.h>
|
||||
|
||||
#include "../inc/m17.h"
|
||||
|
||||
int16_t sample; //raw S16_LE baseband sample
|
||||
int16_t flt_buff[FLT_LEN]; //root-nyquist filter buffer
|
||||
int16_t sw_buff[SW_LEN]; //syncword detection buffer
|
||||
int16_t xc_buff[XC_LEN]; //cross-correlation buffer
|
||||
int16_t mac; //multiply-accumulate
|
||||
|
||||
//states
|
||||
uint8_t pre_syncd=0;
|
||||
uint8_t syncd=0;
|
||||
int8_t phase=0;
|
||||
|
||||
int main(void)
|
||||
{
|
||||
while(1)
|
||||
{
|
||||
//wait for another baseband sample
|
||||
if(fread((uint8_t*)&sample, 2, 1, stdin)<1) break;
|
||||
|
||||
//push the root-nyquist filter's buffer
|
||||
for(uint8_t i=0; i<FLT_LEN-1; i++)
|
||||
{
|
||||
flt_buff[i]=flt_buff[i+1];
|
||||
}
|
||||
|
||||
flt_buff[FLT_LEN-1]=sample;
|
||||
|
||||
//calculate the filter's output
|
||||
mac=0;
|
||||
for(uint8_t i=0; i<FLT_LEN; i++)
|
||||
mac+=flt_buff[i]*taps[i];
|
||||
|
||||
for(uint8_t i=0; i<FLT_LEN-2; i++)
|
||||
{
|
||||
sw_buff[i]=sw_buff[i+1];
|
||||
}
|
||||
|
||||
sw_buff[FLT_LEN-2]=mac;
|
||||
|
||||
//detect syncword using cross-correlation
|
||||
int32_t xcorr=0;
|
||||
|
||||
for(uint8_t i=0; i<XC_LEN; i+=10)
|
||||
{
|
||||
xcorr+=sw_buff[i]*str_sync[i/10];
|
||||
}
|
||||
|
||||
//push the xcorr value to the buffer
|
||||
for(uint8_t i=0; i<XC_LEN-1; i++)
|
||||
{
|
||||
xc_buff[i]=xc_buff[i+1];
|
||||
}
|
||||
|
||||
xc_buff[XC_LEN-1]=xcorr/24;
|
||||
|
||||
//detect peak
|
||||
if(xc_buff[XC_LEN-1]>0.4*INT16_MAX)
|
||||
{
|
||||
fprintf(stderr, "SYNC\n");
|
||||
}
|
||||
}
|
||||
|
||||
return 0;
|
||||
}
|
||||
|
|
@ -1,213 +0,0 @@
|
|||
#include <stdio.h>
|
||||
#include <stdint.h>
|
||||
#include <string.h>
|
||||
#include "viterbi.h"
|
||||
|
||||
#define K 5 //constraint length
|
||||
#define NUM_STATES (1 << (K - 1)) //number of states
|
||||
|
||||
//vars
|
||||
uint32_t prevMetrics[NUM_STATES];
|
||||
uint32_t currMetrics[NUM_STATES];
|
||||
|
||||
uint32_t prevMetricsData[NUM_STATES];
|
||||
uint32_t currMetricsData[NUM_STATES];
|
||||
|
||||
uint16_t history[244];
|
||||
|
||||
/**
|
||||
* Decode unpunctured convolutionally encoded data.
|
||||
*
|
||||
* @param out: destination array where decoded data is written.
|
||||
* @param in: input data.
|
||||
* @param len: input length in bits
|
||||
* @return number of bit errors corrected.
|
||||
*/
|
||||
uint32_t decode(uint8_t* out, const uint16_t* in, uint16_t len)
|
||||
{
|
||||
if(len > 244*2)
|
||||
fprintf(stderr, "Input size exceeds max history\n");
|
||||
|
||||
reset();
|
||||
|
||||
size_t pos = 0;
|
||||
for(size_t i = 0; i < len; i += 2)
|
||||
{
|
||||
uint16_t s0 = in[i];
|
||||
uint16_t s1 = in[i + 1];
|
||||
|
||||
decodeBit(s0, s1, pos);
|
||||
pos++;
|
||||
}
|
||||
|
||||
return chainback(out, pos, len/2);
|
||||
}
|
||||
|
||||
/**
|
||||
* Decode punctured convolutionally encoded data.
|
||||
*
|
||||
* @param out: destination array where decoded data is written.
|
||||
* @param in: input data.
|
||||
* @param punct: puncturing matrix.
|
||||
* @param in_len: input data length.
|
||||
* @param p_len: puncturing matrix length (entries).
|
||||
* @return number of bit errors corrected.
|
||||
*/
|
||||
uint32_t decodePunctured(uint8_t* out, const uint16_t* in, const uint8_t* punct, const uint16_t in_len, const uint16_t p_len)
|
||||
{
|
||||
if(in_len > 244*2)
|
||||
fprintf(stderr, "Input size exceeds max history\n");
|
||||
|
||||
uint16_t umsg[244*2]; //unpunctured message
|
||||
uint8_t p=0; //puncturer matrix entry
|
||||
uint16_t u=0; //bits count - unpunctured message
|
||||
uint16_t i=0; //bits read from the input message
|
||||
|
||||
while(i<in_len)
|
||||
{
|
||||
if(punct[p])
|
||||
{
|
||||
umsg[u]=in[i];
|
||||
i++;
|
||||
}
|
||||
else
|
||||
{
|
||||
umsg[u]=0x7FFF;
|
||||
}
|
||||
|
||||
u++;
|
||||
p++;
|
||||
p%=p_len;
|
||||
}
|
||||
|
||||
return decode(out, umsg, u) - (u-in_len)*0x7FFF;
|
||||
}
|
||||
|
||||
/**
|
||||
* Decode one bit and update trellis.
|
||||
*
|
||||
* @param s0: cost of the first symbol.
|
||||
* @param s1: cost of the second symbol.
|
||||
* @param pos: bit position in history.
|
||||
*/
|
||||
void decodeBit(uint16_t s0, uint16_t s1, size_t pos)
|
||||
{
|
||||
static const uint16_t COST_TABLE_0[] = {0, 0, 0, 0, 0xFFFF, 0xFFFF, 0xFFFF, 0xFFFF};
|
||||
static const uint16_t COST_TABLE_1[] = {0, 0xFFFF, 0xFFFF, 0, 0, 0xFFFF, 0xFFFF, 0};
|
||||
|
||||
for(uint8_t i = 0; i < NUM_STATES/2; i++)
|
||||
{
|
||||
uint32_t metric = q_AbsDiff(COST_TABLE_0[i], s0)
|
||||
+ q_AbsDiff(COST_TABLE_1[i], s1);
|
||||
|
||||
|
||||
uint32_t m0 = prevMetrics[i] + metric;
|
||||
uint32_t m1 = prevMetrics[i + NUM_STATES/2] + (0x1FFFE - metric);
|
||||
|
||||
uint32_t m2 = prevMetrics[i] + (0x1FFFE - metric);
|
||||
uint32_t m3 = prevMetrics[i + NUM_STATES/2] + metric;
|
||||
|
||||
uint8_t i0 = 2 * i;
|
||||
uint8_t i1 = i0 + 1;
|
||||
|
||||
if(m0 >= m1)
|
||||
{
|
||||
history[pos]|=(1<<i0);
|
||||
currMetrics[i0] = m1;
|
||||
}
|
||||
else
|
||||
{
|
||||
history[pos]&=~(1<<i0);
|
||||
currMetrics[i0] = m0;
|
||||
}
|
||||
|
||||
if(m2 >= m3)
|
||||
{
|
||||
history[pos]|=(1<<i1);
|
||||
currMetrics[i1] = m3;
|
||||
}
|
||||
else
|
||||
{
|
||||
history[pos]&=~(1<<i1);
|
||||
currMetrics[i1] = m2;
|
||||
}
|
||||
}
|
||||
|
||||
//swap
|
||||
uint32_t tmp[NUM_STATES];
|
||||
for(uint8_t i=0; i<NUM_STATES; i++)
|
||||
{
|
||||
tmp[i]=currMetrics[i];
|
||||
}
|
||||
for(uint8_t i=0; i<NUM_STATES; i++)
|
||||
{
|
||||
currMetrics[i]=prevMetrics[i];
|
||||
prevMetrics[i]=tmp[i];
|
||||
}
|
||||
}
|
||||
|
||||
/**
|
||||
* History chainback to obtain final byte array.
|
||||
*
|
||||
* @param out: destination byte array for decoded data.
|
||||
* @param pos: starting position for the chainback.
|
||||
* @param len: length of the output in bits.
|
||||
* @return minimum Viterbi cost at the end of the decode sequence.
|
||||
*/
|
||||
uint32_t chainback(uint8_t* out, size_t pos, uint16_t len)
|
||||
{
|
||||
uint8_t state = 0;
|
||||
size_t bitPos = len+4;
|
||||
|
||||
memset(out, 0, (len-1)/8+1);
|
||||
|
||||
while(pos > 0)
|
||||
{
|
||||
bitPos--;
|
||||
pos--;
|
||||
uint16_t bit = history[pos]&((1<<(state>>4)));
|
||||
state >>= 1;
|
||||
if(bit)
|
||||
{
|
||||
state |= 0x80;
|
||||
out[bitPos/8]|=1<<(7-(bitPos%8));
|
||||
}
|
||||
}
|
||||
|
||||
uint32_t cost = prevMetrics[0];
|
||||
|
||||
for(size_t i = 0; i < NUM_STATES; i++)
|
||||
{
|
||||
uint32_t m = prevMetrics[i];
|
||||
if(m < cost) cost = m;
|
||||
}
|
||||
|
||||
return cost;
|
||||
}
|
||||
|
||||
/**
|
||||
* Utility function to compute the absolute value of a difference between
|
||||
* two fixed-point values.
|
||||
*
|
||||
* @param v1: first value
|
||||
* @param v2: second value
|
||||
* @return abs(v1-v2)
|
||||
*/
|
||||
uint16_t q_AbsDiff(const uint16_t v1, const uint16_t v2)
|
||||
{
|
||||
if(v2 > v1) return v2 - v1;
|
||||
return v1 - v2;
|
||||
}
|
||||
|
||||
/**
|
||||
* Reset the decoder state.
|
||||
*
|
||||
*/
|
||||
void reset(void)
|
||||
{
|
||||
memset((uint8_t*)history, 0, 2*244);
|
||||
memset((uint8_t*)currMetrics, 0, 4*NUM_STATES);
|
||||
memset((uint8_t*)prevMetrics, 0, 4*NUM_STATES);
|
||||
memset((uint8_t*)currMetricsData, 0, 4*NUM_STATES);
|
||||
memset((uint8_t*)prevMetricsData, 0, 4*NUM_STATES);
|
||||
}
|
||||
|
|
@ -1,17 +0,0 @@
|
|||
#ifndef VITERBI_H
|
||||
#define VITERBI_H
|
||||
|
||||
#ifdef __cplusplus
|
||||
extern "C" {
|
||||
#endif
|
||||
uint32_t decode(uint8_t* out, const uint16_t* in, uint16_t len);
|
||||
uint32_t decodePunctured(uint8_t* out, const uint16_t* in, const uint8_t* punct, const uint16_t in_len, const uint16_t p_len);
|
||||
void decodeBit(uint16_t s0, uint16_t s1, size_t pos);
|
||||
uint32_t chainback(uint8_t* out, size_t pos, uint16_t len);
|
||||
uint16_t q_AbsDiff(const uint16_t v1, const uint16_t v2);
|
||||
void reset(void);
|
||||
#ifdef __cplusplus
|
||||
}
|
||||
#endif
|
||||
|
||||
#endif
|
||||
|
|
@ -1,10 +1,10 @@
|
|||
all: m17-packet-encode m17-packet-decode
|
||||
|
||||
m17-packet-encode: m17-packet-encode.c crc.c crc.h ../inc/m17.h
|
||||
gcc -O2 -Wall m17-packet-encode.c crc.c -o m17-packet-encode -lm
|
||||
m17-packet-encode: m17-packet-encode.c ../lib/m17lib.c ../lib/m17lib.h
|
||||
gcc -O2 -Wall m17-packet-encode.c ../lib/m17lib.c -o m17-packet-encode -lm
|
||||
|
||||
m17-packet-decode: m17-packet-decode.c viterbi.c viterbi.h crc.c crc.h ../inc/m17.h
|
||||
gcc -O2 -Wall m17-packet-decode.c viterbi.c crc.c -o m17-packet-decode -lm
|
||||
m17-packet-decode: m17-packet-decode.c ../lib/m17lib.c ../lib/m17lib.h
|
||||
gcc -O2 -Wall m17-packet-decode.c ../lib/m17lib.c -o m17-packet-decode -lm
|
||||
|
||||
install: all
|
||||
sudo install m17-packet-encode /usr/local/bin
|
||||
|
|
|
|||
|
|
@ -1,23 +0,0 @@
|
|||
#include <string.h>
|
||||
#include <stdint.h>
|
||||
#include "crc.h"
|
||||
|
||||
const uint16_t M17_CRC_POLY = 0x5935;
|
||||
|
||||
uint16_t CRC_M17(const uint8_t *in, const uint16_t len)
|
||||
{
|
||||
uint32_t crc=0xFFFF; //init val
|
||||
|
||||
for(uint16_t i=0; i<len; i++)
|
||||
{
|
||||
crc^=in[i]<<8;
|
||||
for(uint8_t j=0; j<8; j++)
|
||||
{
|
||||
crc<<=1;
|
||||
if(crc&0x10000)
|
||||
crc=(crc^M17_CRC_POLY)&0xFFFF;
|
||||
}
|
||||
}
|
||||
|
||||
return crc&(0xFFFF);
|
||||
}
|
||||
|
|
@ -1,12 +0,0 @@
|
|||
#ifndef CRC_H
|
||||
#define CRC_H
|
||||
|
||||
#ifdef __cplusplus
|
||||
extern "C" {
|
||||
#endif
|
||||
uint16_t CRC_M17(const uint8_t *in, const uint16_t len);
|
||||
#ifdef __cplusplus
|
||||
}
|
||||
#endif
|
||||
|
||||
#endif
|
||||
|
|
@ -1,228 +0,0 @@
|
|||
#include <string.h>
|
||||
#include <stdint.h>
|
||||
#include "golay.h"
|
||||
|
||||
static const uint16_t encode_matrix[12]=
|
||||
{
|
||||
0x8eb, 0x93e, 0xa97, 0xdc6, 0x367, 0x6cd,
|
||||
0xd99, 0x3da, 0x7b4, 0xf68, 0x63b, 0xc75
|
||||
};
|
||||
|
||||
const uint16_t decode_matrix[12]=
|
||||
{
|
||||
0xc75, 0x49f, 0x93e, 0x6e3, 0xdc6, 0xf13,
|
||||
0xab9, 0x1ed, 0x3da, 0x7b4, 0xf68, 0xa4f
|
||||
};
|
||||
|
||||
//0 index - LSB
|
||||
void IntToSoft(uint16_t* out, const uint16_t in, uint8_t len)
|
||||
{
|
||||
for(uint8_t i=0; i<len; i++)
|
||||
{
|
||||
(in>>i)&1 ? (out[i]=0xFFFF) : (out[i]=0);
|
||||
}
|
||||
}
|
||||
|
||||
uint16_t SoftToInt(const uint16_t* in, uint8_t len)
|
||||
{
|
||||
uint16_t tmp=0;
|
||||
|
||||
for(uint8_t i=0; i<len; i++)
|
||||
{
|
||||
if(in[i]>0x7FFF)
|
||||
tmp|=(1<<i);
|
||||
}
|
||||
|
||||
return tmp;
|
||||
}
|
||||
|
||||
//Quadrant I fixed point division with saturation
|
||||
//result=a/b
|
||||
uint16_t Div16(uint16_t a, uint16_t b)
|
||||
{
|
||||
uint32_t aa=(uint32_t)a<<16;
|
||||
uint32_t r=aa/b;
|
||||
|
||||
if(r<=0xFFFF)
|
||||
return r;
|
||||
else
|
||||
return 0xFFFF;
|
||||
}
|
||||
|
||||
//Quadrant I fixed point multiplication
|
||||
//result=a/b
|
||||
uint16_t Mul16(uint16_t a, uint16_t b)
|
||||
{
|
||||
return (uint16_t)(((uint32_t)a*b)>>16);
|
||||
}
|
||||
|
||||
//use bilinear interpolation for XOR
|
||||
uint16_t SoftBitXOR(const uint16_t a, const uint16_t b)
|
||||
{
|
||||
return Mul16(Div16(0xFFFF-b, 0xFFFF), Div16(a, 0xFFFF)) + Mul16(Div16(b, 0xFFFF), Div16(0xFFFF-a, 0xFFFF));
|
||||
}
|
||||
|
||||
//soft XOR
|
||||
void SoftXOR(uint16_t* out, const uint16_t* a, const uint16_t* b, uint8_t len)
|
||||
{
|
||||
for(uint8_t i=0; i<len; i++)
|
||||
out[i]=SoftBitXOR(a[i], b[i]);
|
||||
}
|
||||
|
||||
//soft equivalent of popcount
|
||||
uint32_t spopcount(const uint16_t* in, uint8_t siz)
|
||||
{
|
||||
uint32_t tmp=0;
|
||||
|
||||
for(uint8_t i=0; i<siz; i++)
|
||||
tmp+=in[i];
|
||||
|
||||
return tmp;
|
||||
}
|
||||
|
||||
void calcChecksumS(uint16_t* out, const uint16_t* value)
|
||||
{
|
||||
uint16_t checksum[12];
|
||||
uint16_t soft_em[12]; //soft valued encoded matrix entry
|
||||
|
||||
for(uint8_t i=0; i<12; i++)
|
||||
checksum[i]=0;
|
||||
|
||||
for(uint8_t i=0; i<12; i++)
|
||||
{
|
||||
IntToSoft(soft_em, encode_matrix[i], 12);
|
||||
|
||||
if(value[i]>0x7FFF)
|
||||
{
|
||||
SoftXOR(checksum, checksum, soft_em, 12);
|
||||
}
|
||||
}
|
||||
|
||||
memcpy((uint8_t*)out, (uint8_t*)checksum, 12*2);
|
||||
}
|
||||
|
||||
uint32_t SdetectErrors(const uint16_t* codeword)
|
||||
{
|
||||
uint16_t data[12];
|
||||
uint16_t parity[12];
|
||||
uint16_t cksum[12];
|
||||
uint16_t syndrome[12];
|
||||
uint32_t weight; //for soft popcount
|
||||
|
||||
memcpy((uint8_t*)data, (uint8_t*)&codeword[12], 2*12);
|
||||
memcpy((uint8_t*)parity, (uint8_t*)&codeword[0], 2*12);
|
||||
|
||||
calcChecksumS(cksum, data);
|
||||
SoftXOR(syndrome, parity, cksum, 12);
|
||||
|
||||
weight=spopcount(syndrome, 12);
|
||||
|
||||
//all (less than 4) errors in the parity part
|
||||
if(weight < 4*0xFFFE)
|
||||
{
|
||||
//printf("1: %1.2f\n", (float)weight/0xFFFF);
|
||||
return SoftToInt(syndrome, 12);
|
||||
}
|
||||
|
||||
//one of the errors in data part, up to 3 in parity
|
||||
for(uint8_t i = 0; i<12; i++)
|
||||
{
|
||||
uint16_t e = 1<<i;
|
||||
uint16_t coded_error = encode_matrix[i];
|
||||
uint16_t scoded_error[12]; //soft coded_error
|
||||
uint16_t sc[12]; //syndrome^coded_error
|
||||
|
||||
IntToSoft(scoded_error, coded_error, 12);
|
||||
SoftXOR(sc, syndrome, scoded_error, 12);
|
||||
weight=spopcount(sc, 12);
|
||||
|
||||
if(weight < 3*0xFFFE)
|
||||
{
|
||||
//printf("2: %1.2f\n", (float)weight/0xFFFF+1);
|
||||
uint16_t s=SoftToInt(syndrome, 12);
|
||||
return (e << 12) | (s ^ coded_error);
|
||||
}
|
||||
}
|
||||
|
||||
//two of the errors in data part and up to 2 in parity
|
||||
for(uint8_t i = 0; i<11; i++)
|
||||
{
|
||||
for(uint8_t j = i+1; j<12; j++)
|
||||
{
|
||||
uint16_t e = (1<<i) | (1<<j);
|
||||
uint16_t coded_error = encode_matrix[i]^encode_matrix[j];
|
||||
uint16_t scoded_error[12]; //soft coded_error
|
||||
uint16_t sc[12]; //syndrome^coded_error
|
||||
|
||||
IntToSoft(scoded_error, coded_error, 12);
|
||||
SoftXOR(sc, syndrome, scoded_error, 12);
|
||||
weight=spopcount(sc, 12);
|
||||
|
||||
if(weight < 2*0xFFFF)
|
||||
{
|
||||
//printf("3: %1.2f\n", (float)weight/0xFFFF+2);
|
||||
uint16_t s=SoftToInt(syndrome, 12);
|
||||
return (e << 12) | (s ^ coded_error);
|
||||
}
|
||||
}
|
||||
}
|
||||
|
||||
//algebraic decoding magic
|
||||
uint16_t inv_syndrome[12]={0,0,0,0,0,0,0,0,0,0,0,0};
|
||||
uint16_t dm[12]; //soft decode matrix
|
||||
|
||||
for(uint8_t i=0; i<12; i++)
|
||||
{
|
||||
if(syndrome[i] > 0x7FFF)
|
||||
{
|
||||
IntToSoft(dm, decode_matrix[i], 12);
|
||||
SoftXOR(inv_syndrome, inv_syndrome, dm, 12);
|
||||
}
|
||||
}
|
||||
|
||||
//all (less than 4) errors in the data part
|
||||
weight=spopcount(inv_syndrome, 12);
|
||||
if(weight < 4*0xFFFF)
|
||||
{
|
||||
//printf("4: %1.2f\n", (float)weight/0xFFFF);
|
||||
return SoftToInt(inv_syndrome, 12) << 12;
|
||||
}
|
||||
|
||||
//one error in parity bits, up to 3 in data - this part has some quirks, the reason remains unknown
|
||||
for(uint8_t i=0; i<12; i++)
|
||||
{
|
||||
uint16_t e = 1<<i;
|
||||
uint16_t coding_error = decode_matrix[i];
|
||||
|
||||
uint16_t ce[12]; //soft coding error
|
||||
uint16_t tmp[12];
|
||||
|
||||
IntToSoft(ce, coding_error, 12);
|
||||
SoftXOR(tmp, inv_syndrome, ce, 12);
|
||||
weight=spopcount(tmp, 12);
|
||||
|
||||
if(weight < 3*(0xFFFF+2))
|
||||
{
|
||||
//printf("5: %1.2f\n", (float)weight/0xFFFF+1);
|
||||
return ((SoftToInt(inv_syndrome, 12) ^ coding_error) << 12) | e;
|
||||
}
|
||||
}
|
||||
|
||||
return 0xFFFFFFFF;
|
||||
}
|
||||
|
||||
//soft decode
|
||||
uint16_t golay24_sdecode(const uint16_t* codeword)
|
||||
{
|
||||
//match the bit order in M17
|
||||
uint16_t cw[24];
|
||||
for(uint8_t i=0; i<24; i++)
|
||||
cw[i]=codeword[23-i];
|
||||
|
||||
uint32_t errors = SdetectErrors(cw);
|
||||
|
||||
if(errors == 0xFFFFFFFF)
|
||||
return 0xFFFF;
|
||||
|
||||
return (((SoftToInt(&cw[0], 16) | (SoftToInt(&cw[16], 8) << 16)) ^ errors) >> 12) & 0x0FFF;
|
||||
}
|
||||
|
|
@ -1,21 +0,0 @@
|
|||
#ifndef GOLAY_H
|
||||
#define GOLAY_H
|
||||
|
||||
#ifdef __cplusplus
|
||||
extern "C" {
|
||||
#endif
|
||||
void IntToSoft(uint16_t* out, const uint16_t in, uint8_t len);
|
||||
uint16_t SoftToInt(const uint16_t* in, uint8_t len);
|
||||
uint16_t Div16(uint16_t a, uint16_t b);
|
||||
uint16_t Mul16(uint16_t a, uint16_t b);
|
||||
uint16_t SoftBitXOR(const uint16_t a, const uint16_t b);
|
||||
void SoftXOR(uint16_t* out, const uint16_t* a, const uint16_t* b, uint8_t len);
|
||||
uint32_t spopcount(const uint16_t* in, uint8_t siz);
|
||||
void calcChecksumS(uint16_t* out, const uint16_t* value);
|
||||
uint32_t SdetectErrors(const uint16_t* codeword);
|
||||
uint16_t golay24_sdecode(const uint16_t* codeword);
|
||||
#ifdef __cplusplus
|
||||
}
|
||||
#endif
|
||||
|
||||
#endif
|
||||
|
|
@ -2,12 +2,8 @@
|
|||
#include <stdlib.h>
|
||||
#include <stdint.h>
|
||||
#include <string.h>
|
||||
#include <math.h>
|
||||
|
||||
#include "../inc/m17.h"
|
||||
#include "golay.h"
|
||||
#include "viterbi.h"
|
||||
#include "crc.h"
|
||||
#include "../lib/m17lib.h"
|
||||
|
||||
float sample; //last raw sample from the stdin
|
||||
float last[8]; //look-back buffer for finding syncwords
|
||||
|
|
@ -30,53 +26,6 @@ uint8_t callsigns=0; //decode callsigns?
|
|||
uint8_t show_viterbi=0; //show Viterbi errors?
|
||||
uint8_t text_only=0; //display text only (for text message mode)
|
||||
|
||||
//decodes a 6-byte long array to a callsign
|
||||
void decode_callsign(uint8_t *outp, const uint8_t *inp)
|
||||
{
|
||||
uint64_t encoded=0;
|
||||
|
||||
//repack the data to a uint64_t
|
||||
for(uint8_t i=0; i<6; i++)
|
||||
encoded|=(uint64_t)inp[5-i]<<(8*i);
|
||||
|
||||
//check if the value is reserved (not a callsign)
|
||||
if(encoded>=262144000000000ULL)
|
||||
{
|
||||
if(encoded==0xFFFFFFFFFFFF) //broadcast
|
||||
{
|
||||
sprintf((char*)outp, "#BCAST");
|
||||
}
|
||||
else
|
||||
{
|
||||
outp[0]=0;
|
||||
}
|
||||
|
||||
return;
|
||||
}
|
||||
|
||||
//decode the callsign
|
||||
uint8_t i=0;
|
||||
while(encoded>0)
|
||||
{
|
||||
outp[i]=" ABCDEFGHIJKLMNOPQRSTUVWXYZ0123456789-/."[encoded%40];
|
||||
encoded/=40;
|
||||
i++;
|
||||
}
|
||||
outp[i]=0;
|
||||
}
|
||||
|
||||
float eucl_norm(const float* in1, const int8_t* in2, uint8_t len)
|
||||
{
|
||||
float tmp = 0.0f;
|
||||
|
||||
for(uint8_t i=0; i<len; i++)
|
||||
{
|
||||
tmp += powf(in1[i]-(float)in2[i], 2.0f);
|
||||
}
|
||||
|
||||
return sqrt(tmp);
|
||||
}
|
||||
|
||||
int main(int argc, char* argv[])
|
||||
{
|
||||
//scan command line options - if there are any
|
||||
|
|
@ -227,7 +176,7 @@ int main(int argc, char* argv[])
|
|||
if(!fl)
|
||||
{
|
||||
//decode
|
||||
uint32_t e=decodePunctured(frame_data, d_soft_bit, P_3, SYM_PER_PLD*2, 8);
|
||||
uint32_t e=viterbi_decode_punctured(frame_data, d_soft_bit, P_3, SYM_PER_PLD*2, 8);
|
||||
|
||||
//dump FN
|
||||
uint8_t rx_fn=(frame_data[26]>>2)&0x1F;
|
||||
|
|
@ -290,7 +239,7 @@ int main(int argc, char* argv[])
|
|||
//fprintf(stderr, "LSF\n");
|
||||
|
||||
//decode
|
||||
uint32_t e=decodePunctured(lsf, d_soft_bit, P_1, 2*SYM_PER_PLD, 61);
|
||||
uint32_t e=viterbi_decode_punctured(lsf, d_soft_bit, P_1, 2*SYM_PER_PLD, 61);
|
||||
|
||||
//shift the buffer 1 position left - get rid of the encoded flushing bits
|
||||
for(uint8_t i=0; i<30; i++)
|
||||
|
|
@ -303,8 +252,8 @@ int main(int argc, char* argv[])
|
|||
{
|
||||
uint8_t d_dst[12], d_src[12]; //decoded strings
|
||||
|
||||
decode_callsign(d_dst, &lsf[0]);
|
||||
decode_callsign(d_src, &lsf[6]);
|
||||
decode_callsign_bytes(d_dst, &lsf[0]);
|
||||
decode_callsign_bytes(d_src, &lsf[6]);
|
||||
|
||||
//DST
|
||||
fprintf(stderr, "DST: %-9s ", d_dst);
|
||||
|
|
|
|||
|
|
@ -4,17 +4,11 @@
|
|||
#include <stdlib.h>
|
||||
#include <math.h>
|
||||
|
||||
#include "../inc/m17.h"
|
||||
#include "crc.h"
|
||||
#include "../lib/m17lib.h"
|
||||
|
||||
struct LSF
|
||||
{
|
||||
uint8_t dst[6];
|
||||
uint8_t src[6];
|
||||
uint8_t type[2];
|
||||
uint8_t meta[112/8];
|
||||
uint8_t crc[2];
|
||||
} lsf;
|
||||
#define FLT_LEN (BSB_SPS*FLT_SPAN+1) //for 48kHz sample rate this is 81
|
||||
|
||||
struct LSF lsf;
|
||||
|
||||
uint8_t enc_bits[SYM_PER_PLD*2]; //type-2 bits, unpacked
|
||||
uint8_t rf_bits[SYM_PER_PLD*2]; //type-4 bits, unpacked
|
||||
|
|
@ -38,7 +32,7 @@ uint8_t out_type=0; //output file type -
|
|||
|
||||
//type - 0 - preamble before LSF (standard)
|
||||
//type - 1 - preamble before BERT transmission
|
||||
void fill_Preamble(float* out, const uint8_t type)
|
||||
void fill_preamble(float* out, const uint8_t type)
|
||||
{
|
||||
if(type) //pre-BERT
|
||||
{
|
||||
|
|
@ -58,13 +52,13 @@ void fill_Preamble(float* out, const uint8_t type)
|
|||
}
|
||||
}
|
||||
|
||||
void fill_Syncword(float* out, uint16_t* cnt, const uint16_t sword)
|
||||
void fill_syncword(float* out, uint16_t* cnt, const uint16_t syncword)
|
||||
{
|
||||
float symb=0.0f;
|
||||
|
||||
for(uint8_t i=0; i<16; i+=2)
|
||||
{
|
||||
symb=symbol_map[(sword>>(14-i))&3];
|
||||
symb=symbol_map[(syncword>>(14-i))&3];
|
||||
out[*cnt]=symb;
|
||||
(*cnt)++;
|
||||
}
|
||||
|
|
@ -83,200 +77,6 @@ void fill_data(float* out, uint16_t* cnt, const uint8_t* in)
|
|||
}
|
||||
}
|
||||
|
||||
//out - unpacked bits
|
||||
//in - packed raw bits
|
||||
void conv_Encode_Frame(uint8_t* out, uint8_t* in)
|
||||
{
|
||||
uint8_t pp_len = sizeof(P_3);
|
||||
uint8_t p=0; //puncturing pattern index
|
||||
uint16_t pb=0; //pushed punctured bits
|
||||
uint8_t ud[206+4+4]; //unpacked data
|
||||
|
||||
memset(ud, 0, 206+4+4);
|
||||
|
||||
//unpack data
|
||||
for(uint8_t i=0; i<26; i++)
|
||||
{
|
||||
for(uint8_t j=0; j<8; j++)
|
||||
{
|
||||
if(i<=24 || j<=5)
|
||||
ud[4+i*8+j]=(in[i]>>(7-j))&1;
|
||||
}
|
||||
}
|
||||
|
||||
//encode
|
||||
for(uint8_t i=0; i<206+4; i++)
|
||||
{
|
||||
uint8_t G1=(ud[i+4] +ud[i+1]+ud[i+0])%2;
|
||||
uint8_t G2=(ud[i+4]+ud[i+3]+ud[i+2] +ud[i+0])%2;
|
||||
|
||||
//fprintf(stderr, "%d%d", G1, G2);
|
||||
|
||||
if(P_3[p])
|
||||
{
|
||||
out[pb]=G1;
|
||||
pb++;
|
||||
}
|
||||
|
||||
p++;
|
||||
p%=pp_len;
|
||||
|
||||
if(P_3[p])
|
||||
{
|
||||
out[pb]=G2;
|
||||
pb++;
|
||||
}
|
||||
|
||||
p++;
|
||||
p%=pp_len;
|
||||
}
|
||||
|
||||
//fprintf(stderr, "pb=%d\n", pb);
|
||||
}
|
||||
|
||||
//out - unpacked bits
|
||||
//in - packed raw bits (LSF struct)
|
||||
void conv_Encode_LSF(uint8_t* out, struct LSF *in)
|
||||
{
|
||||
uint8_t pp_len = sizeof(P_1);
|
||||
uint8_t p=0; //puncturing pattern index
|
||||
uint16_t pb=0; //pushed punctured bits
|
||||
uint8_t ud[240+4+4]; //unpacked data
|
||||
|
||||
memset(ud, 0, 240+4+4);
|
||||
|
||||
//unpack DST
|
||||
for(uint8_t i=0; i<8; i++)
|
||||
{
|
||||
ud[4+i] =((in->dst[0])>>(7-i))&1;
|
||||
ud[4+i+8] =((in->dst[1])>>(7-i))&1;
|
||||
ud[4+i+16]=((in->dst[2])>>(7-i))&1;
|
||||
ud[4+i+24]=((in->dst[3])>>(7-i))&1;
|
||||
ud[4+i+32]=((in->dst[4])>>(7-i))&1;
|
||||
ud[4+i+40]=((in->dst[5])>>(7-i))&1;
|
||||
}
|
||||
|
||||
//unpack SRC
|
||||
for(uint8_t i=0; i<8; i++)
|
||||
{
|
||||
ud[4+i+48]=((in->src[0])>>(7-i))&1;
|
||||
ud[4+i+56]=((in->src[1])>>(7-i))&1;
|
||||
ud[4+i+64]=((in->src[2])>>(7-i))&1;
|
||||
ud[4+i+72]=((in->src[3])>>(7-i))&1;
|
||||
ud[4+i+80]=((in->src[4])>>(7-i))&1;
|
||||
ud[4+i+88]=((in->src[5])>>(7-i))&1;
|
||||
}
|
||||
|
||||
//unpack TYPE
|
||||
for(uint8_t i=0; i<8; i++)
|
||||
{
|
||||
ud[4+i+96] =((in->type[0])>>(7-i))&1;
|
||||
ud[4+i+104]=((in->type[1])>>(7-i))&1;
|
||||
}
|
||||
|
||||
//unpack META
|
||||
for(uint8_t i=0; i<8; i++)
|
||||
{
|
||||
ud[4+i+112]=((in->meta[0])>>(7-i))&1;
|
||||
ud[4+i+120]=((in->meta[1])>>(7-i))&1;
|
||||
ud[4+i+128]=((in->meta[2])>>(7-i))&1;
|
||||
ud[4+i+136]=((in->meta[3])>>(7-i))&1;
|
||||
ud[4+i+144]=((in->meta[4])>>(7-i))&1;
|
||||
ud[4+i+152]=((in->meta[5])>>(7-i))&1;
|
||||
ud[4+i+160]=((in->meta[6])>>(7-i))&1;
|
||||
ud[4+i+168]=((in->meta[7])>>(7-i))&1;
|
||||
ud[4+i+176]=((in->meta[8])>>(7-i))&1;
|
||||
ud[4+i+184]=((in->meta[9])>>(7-i))&1;
|
||||
ud[4+i+192]=((in->meta[10])>>(7-i))&1;
|
||||
ud[4+i+200]=((in->meta[11])>>(7-i))&1;
|
||||
ud[4+i+208]=((in->meta[12])>>(7-i))&1;
|
||||
ud[4+i+216]=((in->meta[13])>>(7-i))&1;
|
||||
}
|
||||
|
||||
//unpack CRC
|
||||
for(uint8_t i=0; i<8; i++)
|
||||
{
|
||||
ud[4+i+224]=((in->crc[0])>>(7-i))&1;
|
||||
ud[4+i+232]=((in->crc[1])>>(7-i))&1;
|
||||
}
|
||||
|
||||
//encode
|
||||
for(uint8_t i=0; i<240+4; i++)
|
||||
{
|
||||
uint8_t G1=(ud[i+4] +ud[i+1]+ud[i+0])%2;
|
||||
uint8_t G2=(ud[i+4]+ud[i+3]+ud[i+2] +ud[i+0])%2;
|
||||
|
||||
//fprintf(stderr, "%d%d", G1, G2);
|
||||
|
||||
if(P_1[p])
|
||||
{
|
||||
out[pb]=G1;
|
||||
pb++;
|
||||
}
|
||||
|
||||
p++;
|
||||
p%=pp_len;
|
||||
|
||||
if(P_1[p])
|
||||
{
|
||||
out[pb]=G2;
|
||||
pb++;
|
||||
}
|
||||
|
||||
p++;
|
||||
p%=pp_len;
|
||||
}
|
||||
|
||||
//fprintf(stderr, "pb=%d\n", pb);
|
||||
}
|
||||
|
||||
uint16_t LSF_CRC(struct LSF *in)
|
||||
{
|
||||
uint8_t d[28];
|
||||
|
||||
memcpy(&d[0], in->dst, 6);
|
||||
memcpy(&d[6], in->src, 6);
|
||||
memcpy(&d[12], in->type, 2);
|
||||
memcpy(&d[14], in->meta, 14);
|
||||
|
||||
return CRC_M17(d, 28);
|
||||
}
|
||||
|
||||
//encode callsign
|
||||
uint8_t encode_callsign(uint64_t* out, const uint8_t* inp)
|
||||
{
|
||||
//assert inp length
|
||||
if(strlen((const char*)inp)>9)
|
||||
{
|
||||
return -1;
|
||||
}
|
||||
|
||||
const uint8_t charMap[40]=" ABCDEFGHIJKLMNOPQRSTUVWXYZ0123456789-/.";
|
||||
|
||||
uint64_t tmp=0;
|
||||
|
||||
if(strcmp((const char*)inp, "ALL")==0)
|
||||
{
|
||||
*out=0xFFFFFFFFFFFF;
|
||||
return 0;
|
||||
}
|
||||
|
||||
for(int8_t i=strlen((const char*)inp)-1; i>=0; i--)
|
||||
{
|
||||
for(uint8_t j=0; j<40; j++)
|
||||
{
|
||||
if(inp[i]==charMap[j])
|
||||
{
|
||||
tmp=tmp*40+j;
|
||||
break;
|
||||
}
|
||||
}
|
||||
}
|
||||
|
||||
*out=tmp;
|
||||
return 0;
|
||||
}
|
||||
|
||||
//main routine
|
||||
int main(int argc, char* argv[])
|
||||
{
|
||||
|
|
@ -433,15 +233,15 @@ int main(int argc, char* argv[])
|
|||
fprintf(stderr, "LSF CRC:\t%04hX\n", lsf_crc);
|
||||
|
||||
//encode LSF data
|
||||
conv_Encode_LSF(enc_bits, &lsf);
|
||||
conv_encode_LSF(enc_bits, &lsf);
|
||||
|
||||
//fill preamble
|
||||
memset((uint8_t*)full_packet, 0, sizeof(float)*(6912+88));
|
||||
fill_Preamble(full_packet, 0);
|
||||
fill_preamble(full_packet, 0);
|
||||
pkt_sym_cnt=SYM_PER_FRA;
|
||||
|
||||
//send LSF syncword
|
||||
fill_Syncword(full_packet, &pkt_sym_cnt, SYNC_LSF);
|
||||
fill_syncword(full_packet, &pkt_sym_cnt, SYNC_LSF);
|
||||
|
||||
//reorder bits
|
||||
for(uint16_t i=0; i<SYM_PER_PLD*2; i++)
|
||||
|
|
@ -468,7 +268,7 @@ int main(int argc, char* argv[])
|
|||
while(num_bytes)
|
||||
{
|
||||
//send packet frame syncword
|
||||
fill_Syncword(full_packet, &pkt_sym_cnt, SYNC_PKT);
|
||||
fill_syncword(full_packet, &pkt_sym_cnt, SYNC_PKT);
|
||||
|
||||
if(num_bytes>=25)
|
||||
{
|
||||
|
|
@ -477,7 +277,7 @@ int main(int argc, char* argv[])
|
|||
fprintf(stderr, "FN:%02d (full frame)\n", pkt_cnt);
|
||||
|
||||
//encode the packet frame
|
||||
conv_Encode_Frame(enc_bits, pkt_chunk);
|
||||
conv_encode_packet_frame(enc_bits, pkt_chunk);
|
||||
|
||||
//reorder bits
|
||||
for(uint16_t i=0; i<SYM_PER_PLD*2; i++)
|
||||
|
|
@ -509,7 +309,7 @@ int main(int argc, char* argv[])
|
|||
fprintf(stderr, "FN:-- (ending frame)\n");
|
||||
|
||||
//encode the packet frame
|
||||
conv_Encode_Frame(enc_bits, pkt_chunk);
|
||||
conv_encode_packet_frame(enc_bits, pkt_chunk);
|
||||
|
||||
//reorder bits
|
||||
for(uint16_t i=0; i<SYM_PER_PLD*2; i++)
|
||||
|
|
@ -547,7 +347,7 @@ int main(int argc, char* argv[])
|
|||
|
||||
//send EOT
|
||||
for(uint8_t i=0; i<SYM_PER_FRA/SYM_PER_SWD; i++) //192/8=24
|
||||
fill_Syncword(full_packet, &pkt_sym_cnt, EOT_MRKR);
|
||||
fill_syncword(full_packet, &pkt_sym_cnt, EOT_MRKR);
|
||||
|
||||
//dump baseband to a file
|
||||
fp=fopen((const char*)fname, "wb");
|
||||
|
|
@ -576,7 +376,7 @@ int main(int argc, char* argv[])
|
|||
|
||||
//calc the sum of products
|
||||
for(uint16_t k=0; k<FLT_LEN; k++)
|
||||
mac+=mem[k]*taps[k]*sqrtf(10.0); //temporary fix for the interpolation gain error
|
||||
mac+=mem[k]*taps_10[k]*sqrtf(10.0); //temporary fix for the interpolation gain error
|
||||
|
||||
//shift the delay line right by 1
|
||||
for(int16_t k=FLT_LEN-1; k>0; k--)
|
||||
|
|
|
|||
|
|
@ -1,213 +0,0 @@
|
|||
#include <stdio.h>
|
||||
#include <stdint.h>
|
||||
#include <string.h>
|
||||
#include "viterbi.h"
|
||||
|
||||
#define K 5 //constraint length
|
||||
#define NUM_STATES (1 << (K - 1)) //number of states
|
||||
|
||||
//vars
|
||||
uint32_t prevMetrics[NUM_STATES];
|
||||
uint32_t currMetrics[NUM_STATES];
|
||||
|
||||
uint32_t prevMetricsData[NUM_STATES];
|
||||
uint32_t currMetricsData[NUM_STATES];
|
||||
|
||||
uint16_t history[244];
|
||||
|
||||
/**
|
||||
* Decode unpunctured convolutionally encoded data.
|
||||
*
|
||||
* @param out: destination array where decoded data is written.
|
||||
* @param in: input data.
|
||||
* @param len: input length in bits
|
||||
* @return number of bit errors corrected.
|
||||
*/
|
||||
uint32_t decode(uint8_t* out, const uint16_t* in, uint16_t len)
|
||||
{
|
||||
if(len > 244*2)
|
||||
fprintf(stderr, "Input size exceeds max history\n");
|
||||
|
||||
reset();
|
||||
|
||||
size_t pos = 0;
|
||||
for(size_t i = 0; i < len; i += 2)
|
||||
{
|
||||
uint16_t s0 = in[i];
|
||||
uint16_t s1 = in[i + 1];
|
||||
|
||||
decodeBit(s0, s1, pos);
|
||||
pos++;
|
||||
}
|
||||
|
||||
return chainback(out, pos, len/2);
|
||||
}
|
||||
|
||||
/**
|
||||
* Decode punctured convolutionally encoded data.
|
||||
*
|
||||
* @param out: destination array where decoded data is written.
|
||||
* @param in: input data.
|
||||
* @param punct: puncturing matrix.
|
||||
* @param in_len: input data length.
|
||||
* @param p_len: puncturing matrix length (entries).
|
||||
* @return number of bit errors corrected.
|
||||
*/
|
||||
uint32_t decodePunctured(uint8_t* out, const uint16_t* in, const uint8_t* punct, const uint16_t in_len, const uint16_t p_len)
|
||||
{
|
||||
if(in_len > 244*2)
|
||||
fprintf(stderr, "Input size exceeds max history\n");
|
||||
|
||||
uint16_t umsg[244*2]; //unpunctured message
|
||||
uint8_t p=0; //puncturer matrix entry
|
||||
uint16_t u=0; //bits count - unpunctured message
|
||||
uint16_t i=0; //bits read from the input message
|
||||
|
||||
while(i<in_len)
|
||||
{
|
||||
if(punct[p])
|
||||
{
|
||||
umsg[u]=in[i];
|
||||
i++;
|
||||
}
|
||||
else
|
||||
{
|
||||
umsg[u]=0x7FFF;
|
||||
}
|
||||
|
||||
u++;
|
||||
p++;
|
||||
p%=p_len;
|
||||
}
|
||||
|
||||
return decode(out, umsg, u) - (u-in_len)*0x7FFF;
|
||||
}
|
||||
|
||||
/**
|
||||
* Decode one bit and update trellis.
|
||||
*
|
||||
* @param s0: cost of the first symbol.
|
||||
* @param s1: cost of the second symbol.
|
||||
* @param pos: bit position in history.
|
||||
*/
|
||||
void decodeBit(uint16_t s0, uint16_t s1, size_t pos)
|
||||
{
|
||||
static const uint16_t COST_TABLE_0[] = {0, 0, 0, 0, 0xFFFF, 0xFFFF, 0xFFFF, 0xFFFF};
|
||||
static const uint16_t COST_TABLE_1[] = {0, 0xFFFF, 0xFFFF, 0, 0, 0xFFFF, 0xFFFF, 0};
|
||||
|
||||
for(uint8_t i = 0; i < NUM_STATES/2; i++)
|
||||
{
|
||||
uint32_t metric = q_AbsDiff(COST_TABLE_0[i], s0)
|
||||
+ q_AbsDiff(COST_TABLE_1[i], s1);
|
||||
|
||||
|
||||
uint32_t m0 = prevMetrics[i] + metric;
|
||||
uint32_t m1 = prevMetrics[i + NUM_STATES/2] + (0x1FFFE - metric);
|
||||
|
||||
uint32_t m2 = prevMetrics[i] + (0x1FFFE - metric);
|
||||
uint32_t m3 = prevMetrics[i + NUM_STATES/2] + metric;
|
||||
|
||||
uint8_t i0 = 2 * i;
|
||||
uint8_t i1 = i0 + 1;
|
||||
|
||||
if(m0 >= m1)
|
||||
{
|
||||
history[pos]|=(1<<i0);
|
||||
currMetrics[i0] = m1;
|
||||
}
|
||||
else
|
||||
{
|
||||
history[pos]&=~(1<<i0);
|
||||
currMetrics[i0] = m0;
|
||||
}
|
||||
|
||||
if(m2 >= m3)
|
||||
{
|
||||
history[pos]|=(1<<i1);
|
||||
currMetrics[i1] = m3;
|
||||
}
|
||||
else
|
||||
{
|
||||
history[pos]&=~(1<<i1);
|
||||
currMetrics[i1] = m2;
|
||||
}
|
||||
}
|
||||
|
||||
//swap
|
||||
uint32_t tmp[NUM_STATES];
|
||||
for(uint8_t i=0; i<NUM_STATES; i++)
|
||||
{
|
||||
tmp[i]=currMetrics[i];
|
||||
}
|
||||
for(uint8_t i=0; i<NUM_STATES; i++)
|
||||
{
|
||||
currMetrics[i]=prevMetrics[i];
|
||||
prevMetrics[i]=tmp[i];
|
||||
}
|
||||
}
|
||||
|
||||
/**
|
||||
* History chainback to obtain final byte array.
|
||||
*
|
||||
* @param out: destination byte array for decoded data.
|
||||
* @param pos: starting position for the chainback.
|
||||
* @param len: length of the output in bits.
|
||||
* @return minimum Viterbi cost at the end of the decode sequence.
|
||||
*/
|
||||
uint32_t chainback(uint8_t* out, size_t pos, uint16_t len)
|
||||
{
|
||||
uint8_t state = 0;
|
||||
size_t bitPos = len+4;
|
||||
|
||||
memset(out, 0, (len-1)/8+1);
|
||||
|
||||
while(pos > 0)
|
||||
{
|
||||
bitPos--;
|
||||
pos--;
|
||||
uint16_t bit = history[pos]&((1<<(state>>4)));
|
||||
state >>= 1;
|
||||
if(bit)
|
||||
{
|
||||
state |= 0x80;
|
||||
out[bitPos/8]|=1<<(7-(bitPos%8));
|
||||
}
|
||||
}
|
||||
|
||||
uint32_t cost = prevMetrics[0];
|
||||
|
||||
for(size_t i = 0; i < NUM_STATES; i++)
|
||||
{
|
||||
uint32_t m = prevMetrics[i];
|
||||
if(m < cost) cost = m;
|
||||
}
|
||||
|
||||
return cost;
|
||||
}
|
||||
|
||||
/**
|
||||
* Utility function to compute the absolute value of a difference between
|
||||
* two fixed-point values.
|
||||
*
|
||||
* @param v1: first value
|
||||
* @param v2: second value
|
||||
* @return abs(v1-v2)
|
||||
*/
|
||||
uint16_t q_AbsDiff(const uint16_t v1, const uint16_t v2)
|
||||
{
|
||||
if(v2 > v1) return v2 - v1;
|
||||
return v1 - v2;
|
||||
}
|
||||
|
||||
/**
|
||||
* Reset the decoder state.
|
||||
*
|
||||
*/
|
||||
void reset(void)
|
||||
{
|
||||
memset((uint8_t*)history, 0, 2*244);
|
||||
memset((uint8_t*)currMetrics, 0, 4*NUM_STATES);
|
||||
memset((uint8_t*)prevMetrics, 0, 4*NUM_STATES);
|
||||
memset((uint8_t*)currMetricsData, 0, 4*NUM_STATES);
|
||||
memset((uint8_t*)prevMetricsData, 0, 4*NUM_STATES);
|
||||
}
|
||||
|
|
@ -1,17 +0,0 @@
|
|||
#ifndef VITERBI_H
|
||||
#define VITERBI_H
|
||||
|
||||
#ifdef __cplusplus
|
||||
extern "C" {
|
||||
#endif
|
||||
uint32_t decode(uint8_t* out, const uint16_t* in, uint16_t len);
|
||||
uint32_t decodePunctured(uint8_t* out, const uint16_t* in, const uint8_t* punct, const uint16_t in_len, const uint16_t p_len);
|
||||
void decodeBit(uint16_t s0, uint16_t s1, size_t pos);
|
||||
uint32_t chainback(uint8_t* out, size_t pos, uint16_t len);
|
||||
uint16_t q_AbsDiff(const uint16_t v1, const uint16_t v2);
|
||||
void reset(void);
|
||||
#ifdef __cplusplus
|
||||
}
|
||||
#endif
|
||||
|
||||
#endif
|
||||
Ładowanie…
Reference in New Issue