williamp/osmocom-analog
1
0
Fork 0
Code Issues Pull Requests Actions Packages Projects Releases Wiki Activity

Automatic FSK polarity selection on TX side

Browse Source 
This is done by simulating two cells with different polarities.
On first message from mobile station, the cell with the correct
polarity is used, the other is disabled.

On RX side the polarity is not selected, since FSK decoder detects
polarity for every frame.
This commit is contained in:
Andreas Eversberg
2016-05-10 19:25:07 +02:00
parent 021c34a899
commit e2a9c2c6a5
9 changed files with 211 additions and 98 deletions
Download Patch File Download Diff File Expand all files Collapse all files

53
src/cnetz/telegramm.c
View File

@@ -26,6 +26,7 @@
#include "../common/debug.h"
#include "../common/timer.h"
#include "cnetz.h"
#include "dsp.h"
#include "sysinfo.h"
#include "telegramm.h"
@@ -570,12 +571,13 @@ static int encode_dialstring(uint64_t *value, const char *number)
return 0;
}
int match_fuz(telegramm_t *telegramm)
int match_fuz(cnetz_t *cnetz, telegramm_t *telegramm, int cell)
{
if (telegramm->fuz_nationalitaet != si.fuz_nat
|| telegramm->fuz_fuvst_nr != si.fuz_fuvst
|| telegramm->fuz_rest_nr != si.fuz_rest) {
PDEBUG(DFRAME, DEBUG_NOTICE, "Ignoring message from mobile phone %d,%d,%d: Cell 'Funkzelle' does not match!\n", telegramm->futln_nationalitaet, telegramm->futln_heimat_fuvst_nr, telegramm->futln_rest_nr);
if (telegramm->fuz_nationalitaet != si[cell].fuz_nat
|| telegramm->fuz_fuvst_nr != si[cell].fuz_fuvst
|| telegramm->fuz_rest_nr != si[cell].fuz_rest) {
if (!cnetz->cell_auto)
PDEBUG(DFRAME, DEBUG_NOTICE, "Ignoring message from mobile phone %d,%d,%d: Cell 'Funkzelle' does not match!\n", telegramm->futln_nationalitaet, telegramm->futln_heimat_fuvst_nr, telegramm->futln_rest_nr);
return 0;
}
@@ -618,7 +620,7 @@ static void debug_parameter(char digit, uint64_t value)
/* encode telegram to 70 bits
* bit order MSB
*/
static const char *assemble_telegramm(const telegramm_t *telegramm, int debug)
static char *assemble_telegramm(const telegramm_t *telegramm, int debug)
{
static char bits[71]; /* + termination char for debug */
char parameter;
@@ -1273,7 +1275,7 @@ int detect_sync(uint64_t bitstream)
* input: 70 data bits MSB first
* output: 10*15 code words (LSB first)
* FTZ 171 TR 60 / 5.1.1.3 */
static const char *encode(const char *input)
static char *encode(const char *input)
{
static char output[150];
int16_t word;
@@ -1389,7 +1391,7 @@ static const char *decode(const char *input, int *_bit_errors)
* input: 10*15 code words (LSB first)
* output: stream of 33 sync + 1 + 150 interleaved bits
* FTZ 171 TR 60 / 5.1.1.2 and 5.1.1.2 */
static const char *interleave(const char *input)
static char *interleave(const char *input)
{
static char output[185]; /* + termination char for debug */
int i, j;
@@ -1488,9 +1490,9 @@ void cnetz_decode_telegramm(cnetz_t *cnetz, const char *bits, double level, doub
telegramm.jitter = jitter;
if (bit_errors)
PDEBUG(DDSP, DEBUG_INFO, "RX Level: %.0f%% Jitter: %.2f Sync Time: %.2f Bit errors: %d %s\n", fabs(level * 32767.0 / cnetz->fsk_deviation) * 100.0, jitter, sync_time, bit_errors, (level < 0) ? "NEGATIVE" : "POSITIVE");
PDEBUG(DDSP, DEBUG_INFO, "RX Level: %.0f%% Jitter: %.2f Sync Time: %.2f (TS %.2f) Bit errors: %d %s\n", fabs(level) * 32767.0 / cnetz->fsk_deviation * 100.0, jitter, sync_time, sync_time / 396.0, bit_errors, (level < 0) ? "NEGATIVE" : "POSITIVE");
else
PDEBUG(DDSP, DEBUG_INFO, "RX Level: %.0f%% Jitter: %.2f Sync Time: %.2f %s\n", fabs(level * 32767.0 / cnetz->fsk_deviation) * 100.0, jitter, sync_time, (level < 0) ? "NEGATIVE" : "POSITIVE");
PDEBUG(DDSP, DEBUG_INFO, "RX Level: %.0f%% Jitter: %.2f Sync Time: %.2f (TS %.2f) %s\n", fabs(level) * 32767.0 / cnetz->fsk_deviation * 100.0, jitter, sync_time, sync_time / 396.0, (level < 0) ? "NEGATIVE" : "POSITIVE");
if (cnetz->sender.loopback) {
PDEBUG(DFRAME, DEBUG_NOTICE, "Received Telegramm in loopback test mode (opcode %d = %s)\n", opcode, definition_opcode[opcode].message_name);
@@ -1508,13 +1510,32 @@ void cnetz_decode_telegramm(cnetz_t *cnetz, const char *bits, double level, doub
return;
}
/* auto select cell */
if (cnetz->cell_auto) {
if (!match_fuz(cnetz, &telegramm, 0)) {
cnetz->cell_nr = 1;
selected:
cnetz->cell_auto = 0;
printf("***********************************************\n");
printf("*** Autoselecting %stive FSK TX polarity! ***\n", (si[cnetz->cell_nr].flip_polarity) ? "nega" : "posi");
printf("***********************************************\n");
} else if (!match_fuz(cnetz, &telegramm, 1)) {
cnetz->cell_nr = 0;
goto selected;
} else {
PDEBUG(DFRAME, DEBUG_NOTICE, "Received Telegramm with no cell number, ignoring!\n");
return;
}
}
switch (cnetz->dsp_mode) {
case DSP_MODE_OGK:
if (definition_opcode[opcode].block != BLOCK_R && definition_opcode[opcode].block != BLOCK_M) {
PDEBUG(DFRAME, DEBUG_NOTICE, "Received Telegramm that is not used OgK channel signalling, ignoring! (opcode %d = %s)\n", opcode, definition_opcode[opcode].message_name);
return;
}
block = cnetz->last_tx_timeslot * 2;
/* determine block by last timeslot sent and by message type */
block = cnetz->sched_last_ts[cnetz->cell_nr] * 2;
if (definition_opcode[opcode].block == BLOCK_M)
block++;
cnetz_receive_telegramm_ogk(cnetz, &telegramm, block);
@@ -1542,7 +1563,7 @@ const char *cnetz_encode_telegramm(cnetz_t *cnetz)
{
const telegramm_t *telegramm = NULL;
uint8_t opcode;
const char *bits;
char *bits;
switch (cnetz->dsp_mode) {
case DSP_MODE_OGK:
@@ -1566,6 +1587,14 @@ const char *cnetz_encode_telegramm(cnetz_t *cnetz)
bits = encode(bits);
bits = interleave(bits);
/* invert, if polarity of the cell is negative */
if (si[cnetz->cell_nr].flip_polarity) {
int i;
for (i = 0; i < 184; i++)
bits[i] ^= 1;
}
return bits;
}