590 lines
11 KiB
C
590 lines
11 KiB
C
|
|
#include <stdio.h>
|
|
#include <stdint.h>
|
|
#include <string.h>
|
|
#include <stdlib.h>
|
|
|
|
#include <osmocom/core/bits.h>
|
|
#include <osmocom/core/conv.h>
|
|
#include <osmocom/core/crcgen.h>
|
|
#include <osmocom/codec/codec.h>
|
|
|
|
#include "gsm0503_conv.h"
|
|
#include "gsm0503_parity.h"
|
|
#include "gsm0503_mapping.h"
|
|
#include "gsm0503_interleaving.h"
|
|
#include "gsm0503_tables.h"
|
|
#include "gsm0503_coding.h"
|
|
|
|
static int _xcch_decode_cB(uint8_t *l2_data, sbit_t *cB)
|
|
{
|
|
ubit_t conv[224];
|
|
int rv;
|
|
|
|
osmo_conv_decode(&gsm0503_conv_xcch, cB, conv);
|
|
|
|
rv = osmo_crc64gen_check_bits(&gsm0503_fire_crc40, conv, 184, conv+184);
|
|
if (rv)
|
|
return -1;
|
|
|
|
osmo_ubit2pbit_ext(l2_data, 0, conv, 0, 184, 1);
|
|
|
|
return 0;
|
|
}
|
|
|
|
static int _xcch_encode_cB(ubit_t *cB, uint8_t *l2_data)
|
|
{
|
|
ubit_t conv[224];
|
|
|
|
osmo_pbit2ubit_ext(conv, 0, l2_data, 0, 184, 1);
|
|
|
|
osmo_crc64gen_set_bits(&gsm0503_fire_crc40, conv, 184, conv+184);
|
|
|
|
osmo_conv_encode(&gsm0503_conv_xcch, conv, cB);
|
|
|
|
return 0;
|
|
}
|
|
|
|
|
|
/*
|
|
* GSM xCCH block transcoding
|
|
*/
|
|
|
|
int xcch_decode(uint8_t *l2_data, sbit_t *bursts)
|
|
{
|
|
sbit_t iB[456], cB[456];
|
|
int i;
|
|
|
|
for (i=0; i<4; i++)
|
|
gsm0503_xcch_burst_unmap(&iB[i * 114], &bursts[i * 116], NULL,
|
|
NULL);
|
|
|
|
gsm0503_xcch_deinterleave(cB, iB);
|
|
|
|
return _xcch_decode_cB(l2_data, cB);
|
|
}
|
|
|
|
int xcch_encode(ubit_t *bursts, uint8_t *l2_data)
|
|
{
|
|
ubit_t iB[456], cB[456], hl = 1, hn = 1;
|
|
int i;
|
|
|
|
_xcch_encode_cB(cB, l2_data);
|
|
|
|
gsm0503_xcch_interleave(cB, iB);
|
|
|
|
for (i=0; i<4; i++)
|
|
gsm0503_xcch_burst_map(&iB[i * 114], &bursts[i * 116], &hl,
|
|
&hn);
|
|
|
|
return 0;
|
|
}
|
|
|
|
|
|
/*
|
|
* GSM PDTCH block transcoding
|
|
*/
|
|
|
|
int pdtch_decode(uint8_t *l2_data, sbit_t *bursts, uint8_t *usf_p)
|
|
{
|
|
sbit_t iB[456], cB[676], hl_hn[8];
|
|
ubit_t conv[456];
|
|
int i, j, k, rv, best = 0, cs = 0, usf = 0; /* make GCC happy */
|
|
|
|
for (i=0; i<4; i++)
|
|
gsm0503_xcch_burst_unmap(&iB[i * 114], &bursts[i * 116],
|
|
hl_hn + i*2, hl_hn + i*2 + 1);
|
|
|
|
for (i=0; i<4; i++) {
|
|
for (j=0, k=0; j<8; j++)
|
|
k += abs(((int)gsm0503_pdtch_hl_hn_sbit[i][j]) -
|
|
((int)hl_hn[j]));
|
|
if (i == 0 || k < best) {
|
|
best = k;
|
|
cs = i+1;
|
|
}
|
|
}
|
|
|
|
gsm0503_xcch_deinterleave(cB, iB);
|
|
|
|
switch (cs) {
|
|
case 1:
|
|
osmo_conv_decode(&gsm0503_conv_xcch, cB, conv);
|
|
|
|
rv = osmo_crc64gen_check_bits(&gsm0503_fire_crc40, conv, 184,
|
|
conv+184);
|
|
if (rv)
|
|
return -1;
|
|
|
|
osmo_ubit2pbit_ext(l2_data, 0, conv, 0, 184, 1);
|
|
|
|
return 23;
|
|
case 2:
|
|
for (i=587, j=455; i>=0; i--)
|
|
if (!gsm0503_puncture_cs2[i])
|
|
cB[i] = cB[j--];
|
|
else
|
|
cB[i] = 0;
|
|
|
|
osmo_conv_decode(&gsm0503_conv_cs2, cB, conv);
|
|
|
|
for (i=0; i<8; i++) {
|
|
for (j=0, k=0; j<6; j++)
|
|
k += abs(((int)gsm0503_usf2six[i][j]) -
|
|
((int)conv[j]));
|
|
if (i == 0 || k < best) {
|
|
best = k;
|
|
usf = i;
|
|
}
|
|
}
|
|
|
|
conv[3] = usf & 1;
|
|
conv[4] = (usf >> 1) & 1;
|
|
conv[5] = (usf >> 2) & 1;
|
|
if (usf_p)
|
|
*usf_p = usf;
|
|
|
|
rv = osmo_crc16gen_check_bits(&gsm0503_cs234_crc16, conv+3, 271,
|
|
conv+3+271);
|
|
if (rv)
|
|
return -1;
|
|
|
|
osmo_ubit2pbit_ext(l2_data, 0, conv, 3, 271, 1);
|
|
|
|
return 34;
|
|
case 3:
|
|
for (i=675, j=455; i>=0; i--)
|
|
if (!gsm0503_puncture_cs3[i])
|
|
cB[i] = cB[j--];
|
|
else
|
|
cB[i] = 0;
|
|
|
|
osmo_conv_decode(&gsm0503_conv_cs3, cB, conv);
|
|
|
|
for (i=0; i<8; i++) {
|
|
for (j=0, k=0; j<6; j++)
|
|
k += abs(((int)gsm0503_usf2six[i][j]) -
|
|
((int)conv[j]));
|
|
if (i == 0 || k < best) {
|
|
best = k;
|
|
usf = i;
|
|
}
|
|
}
|
|
|
|
conv[3] = usf & 1;
|
|
conv[4] = (usf >> 1) & 1;
|
|
conv[5] = (usf >> 2) & 1;
|
|
if (usf_p)
|
|
*usf_p = usf;
|
|
|
|
rv = osmo_crc16gen_check_bits(&gsm0503_cs234_crc16, conv+3, 315,
|
|
conv+3+315);
|
|
if (rv)
|
|
return -1;
|
|
|
|
osmo_ubit2pbit_ext(l2_data, 0, conv, 3, 315, 1);
|
|
|
|
return 40;
|
|
case 4:
|
|
for (i=12; i<456;i++)
|
|
conv[i] = (cB[i] < 0) ? 1:0;
|
|
|
|
for (i=0; i<8; i++) {
|
|
for (j=0, k=0; j<12; j++)
|
|
k += abs(((int)gsm0503_usf2twelve_sbit[i][j]) -
|
|
((int)cB[j]));
|
|
if (i == 0 || k < best) {
|
|
best = k;
|
|
usf = i;
|
|
}
|
|
}
|
|
|
|
conv[9] = usf & 1;
|
|
conv[10] = (usf >> 1) & 1;
|
|
conv[11] = (usf >> 2) & 1;
|
|
if (usf_p)
|
|
*usf_p = usf;
|
|
|
|
rv = osmo_crc16gen_check_bits(&gsm0503_cs234_crc16, conv+9, 431,
|
|
conv+9+431);
|
|
if (rv)
|
|
return -1;
|
|
|
|
osmo_ubit2pbit_ext(l2_data, 0, conv, 9, 431, 1);
|
|
|
|
return 54;
|
|
}
|
|
|
|
return -1;
|
|
}
|
|
|
|
int pdtch_encode(ubit_t *bursts, uint8_t *l2_data, uint8_t l2_len)
|
|
{
|
|
ubit_t iB[456], cB[676];
|
|
const ubit_t *hl_hn;
|
|
ubit_t conv[334];
|
|
int i, j, usf;
|
|
|
|
switch (l2_len) {
|
|
case 23:
|
|
osmo_pbit2ubit_ext(conv, 0, l2_data, 0, 184, 1);
|
|
|
|
osmo_crc64gen_set_bits(&gsm0503_fire_crc40, conv, 184,
|
|
conv+184);
|
|
|
|
osmo_conv_encode(&gsm0503_conv_xcch, conv, cB);
|
|
|
|
hl_hn = gsm0503_pdtch_hl_hn_ubit[0];
|
|
|
|
break;
|
|
case 34:
|
|
osmo_pbit2ubit_ext(conv, 3, l2_data, 0, 271, 1);
|
|
usf = l2_data[0] & 0x7;
|
|
|
|
osmo_crc16gen_set_bits(&gsm0503_cs234_crc16, conv+3, 271,
|
|
conv+3+271);
|
|
|
|
memcpy(conv, gsm0503_usf2six[usf], 6);
|
|
|
|
osmo_conv_encode(&gsm0503_conv_cs2, conv, cB);
|
|
|
|
for (i=0, j=0; i<588; i++)
|
|
if (!gsm0503_puncture_cs2[i])
|
|
cB[j++] = cB[i];
|
|
|
|
hl_hn = gsm0503_pdtch_hl_hn_ubit[1];
|
|
|
|
break;
|
|
case 40:
|
|
osmo_pbit2ubit_ext(conv, 3, l2_data, 0, 315, 1);
|
|
usf = l2_data[0] & 0x7;
|
|
|
|
osmo_crc16gen_set_bits(&gsm0503_cs234_crc16, conv+3, 315,
|
|
conv+3+315);
|
|
|
|
memcpy(conv, gsm0503_usf2six[usf], 6);
|
|
|
|
osmo_conv_encode(&gsm0503_conv_cs3, conv, cB);
|
|
|
|
for (i=0, j=0; i<676; i++)
|
|
if (!gsm0503_puncture_cs3[i])
|
|
cB[j++] = cB[i];
|
|
|
|
hl_hn = gsm0503_pdtch_hl_hn_ubit[2];
|
|
|
|
break;
|
|
case 54:
|
|
osmo_pbit2ubit_ext(cB, 9, l2_data, 0, 431, 1);
|
|
usf = l2_data[0] & 0x7;
|
|
|
|
osmo_crc16gen_set_bits(&gsm0503_cs234_crc16, cB+9, 431,
|
|
cB+9+431);
|
|
|
|
memcpy(cB, gsm0503_usf2twelve_ubit[usf], 12);
|
|
|
|
hl_hn = gsm0503_pdtch_hl_hn_ubit[3];
|
|
|
|
break;
|
|
default:
|
|
return -1;
|
|
}
|
|
|
|
gsm0503_xcch_interleave(cB, iB);
|
|
|
|
for (i=0; i<4; i++)
|
|
gsm0503_xcch_burst_map(&iB[i * 114], &bursts[i * 116],
|
|
hl_hn + i*2, hl_hn + i*2 + 1);
|
|
|
|
return 0;
|
|
}
|
|
|
|
|
|
/*
|
|
* GSM TCH/F FR transcoding
|
|
*/
|
|
|
|
static void tch_fr_reassemble(uint8_t *tch_data, ubit_t *b_bits, int net_order)
|
|
{
|
|
int i, j, k, l, o;
|
|
|
|
tch_data[0] = 0xd << 4;
|
|
memset(tch_data + 1, 0, 32);
|
|
|
|
if (net_order) {
|
|
i = 0; /* counts bits */
|
|
j = 4; /* counts output bits */
|
|
while (i < 260) {
|
|
tch_data[j>>3] |= (b_bits[i] << (7-(j&7)));
|
|
i++;
|
|
j++;
|
|
}
|
|
return;
|
|
}
|
|
|
|
/* reassemble d-bits */
|
|
i = 0; /* counts bits */
|
|
j = 4; /* counts output bits */
|
|
k = gsm0503_gsm_fr_map[0]-1; /* current number bit in element */
|
|
l = 0; /* counts element bits */
|
|
o = 0; /* offset input bits */
|
|
while (i < 260) {
|
|
tch_data[j>>3] |= (b_bits[k+o] << (7-(j&7)));
|
|
if (--k < 0) {
|
|
o += gsm0503_gsm_fr_map[l];
|
|
k = gsm0503_gsm_fr_map[++l]-1;
|
|
}
|
|
i++;
|
|
j++;
|
|
}
|
|
|
|
/* rearrange according to Table 2 of TS 05.03 */
|
|
}
|
|
|
|
static void tch_fr_disassemble(ubit_t *b_bits, uint8_t *tch_data, int net_order)
|
|
{
|
|
int i, j, k, l, o;
|
|
|
|
if (net_order) {
|
|
i = 0; /* counts bits */
|
|
j = 4; /* counts output bits */
|
|
while (i < 260) {
|
|
b_bits[i] = (tch_data[j>>3] >> (7-(j&7))) & 1;
|
|
i++;
|
|
j++;
|
|
}
|
|
return;
|
|
}
|
|
|
|
i = 0; /* counts bits */
|
|
j = 4; /* counts input bits */
|
|
k = gsm0503_gsm_fr_map[0]-1; /* current number bit in element */
|
|
l = 0; /* counts element bits */
|
|
o = 0; /* offset output bits */
|
|
while (i < 260) {
|
|
b_bits[k+o] = (tch_data[j>>3] >> (7-(j&7))) & 1;
|
|
if (--k < 0) {
|
|
o += gsm0503_gsm_fr_map[l];
|
|
k = gsm0503_gsm_fr_map[++l]-1;
|
|
}
|
|
i++;
|
|
j++;
|
|
}
|
|
|
|
}
|
|
|
|
static void tch_fr_d_to_b(ubit_t *b_bits, ubit_t *d_bits)
|
|
{
|
|
int i;
|
|
|
|
for (i = 0; i < 260; i++)
|
|
b_bits[gsm610_bitorder[i]] = d_bits[i];
|
|
}
|
|
|
|
static void tch_fr_b_to_d(ubit_t *d_bits, ubit_t *b_bits)
|
|
{
|
|
int i;
|
|
|
|
for (i = 0; i < 260; i++)
|
|
d_bits[i] = b_bits[gsm610_bitorder[i]];
|
|
}
|
|
|
|
static void tch_fr_unreorder(ubit_t *d, ubit_t *p, ubit_t *u)
|
|
{
|
|
int i;
|
|
|
|
for (i=0; i<91; i++) {
|
|
d[i<<1] = u[i];
|
|
d[(i<<1)+1] = u[184-i];
|
|
}
|
|
for (i=0; i<3; i++)
|
|
p[i] = u[91+i];
|
|
}
|
|
|
|
static void tch_fr_reorder(ubit_t *u, ubit_t *d, ubit_t *p)
|
|
{
|
|
int i;
|
|
|
|
for (i=0; i<91; i++) {
|
|
u[i] = d[i<<1];
|
|
u[184-i] = d[(i<<1)+1];
|
|
}
|
|
for (i=0; i<3; i++)
|
|
u[91+i] = p[i];
|
|
}
|
|
|
|
int tch_fr_decode(uint8_t *tch_data, sbit_t *bursts, int net_order)
|
|
{
|
|
sbit_t iB[912], cB[456], h;
|
|
ubit_t conv[185], b[260], d[260], p[3];
|
|
int i, rv, len, steal = 0;
|
|
|
|
for (i=0; i<8; i++) {
|
|
gsm0503_tch_fr_burst_unmap(&iB[i * 114], &bursts[i * 116], &h,
|
|
i>>2);
|
|
steal -= h;
|
|
}
|
|
|
|
gsm0503_tch_fr_deinterleave(cB, iB);
|
|
|
|
if (steal <= 0) {
|
|
osmo_conv_decode(&gsm0503_conv_tch_fr, cB, conv);
|
|
|
|
tch_fr_unreorder(d, p, conv);
|
|
|
|
for (i=0; i<78; i++)
|
|
d[i+182] = (cB[i+378] < 0) ? 1:0;
|
|
|
|
rv = osmo_crc8gen_check_bits(&gsm0503_tch_fr_crc3, d, 50, p);
|
|
if (rv)
|
|
return -1;
|
|
|
|
tch_fr_d_to_b(b, d);
|
|
|
|
tch_fr_reassemble(tch_data, b, net_order);
|
|
|
|
len = 33;
|
|
} else {
|
|
rv = _xcch_decode_cB(tch_data, cB);
|
|
if (rv)
|
|
return -1;
|
|
|
|
len = 23;
|
|
}
|
|
|
|
return len;
|
|
}
|
|
|
|
int tch_fr_encode(ubit_t *bursts, uint8_t *tch_data, int len, int net_order)
|
|
{
|
|
ubit_t iB[912], cB[456], h;
|
|
ubit_t conv[185], b[260], d[260], p[3];
|
|
int i;
|
|
|
|
switch (len) {
|
|
case 33: /* TCH FR */
|
|
tch_fr_disassemble(b, tch_data, net_order);
|
|
|
|
tch_fr_b_to_d(d, b);
|
|
|
|
osmo_crc8gen_set_bits(&gsm0503_tch_fr_crc3, d, 50, p);
|
|
|
|
tch_fr_reorder(conv, d, p);
|
|
|
|
memcpy(cB+378, d+182, 78);
|
|
|
|
osmo_conv_encode(&gsm0503_conv_tch_fr, conv, cB);
|
|
|
|
h = 0;
|
|
|
|
break;
|
|
case 23: /* FACCH */
|
|
_xcch_encode_cB(cB, tch_data);
|
|
|
|
h = 1;
|
|
|
|
break;
|
|
default:
|
|
return -1;
|
|
}
|
|
|
|
gsm0503_tch_fr_interleave(cB, iB);
|
|
|
|
for (i=0; i<8; i++)
|
|
gsm0503_tch_fr_burst_map(&iB[i * 114], &bursts[i * 116], &h,
|
|
i>>2);
|
|
|
|
return 0;
|
|
}
|
|
|
|
|
|
/*
|
|
* GSM RACH transcoding
|
|
*/
|
|
|
|
/*
|
|
* GSM RACH apply BSIC to parity
|
|
*
|
|
* p(j) = p(j) xor b(j) j = 0, ..., 5
|
|
* b(0) = MSB of PLMN colour code
|
|
* b(5) = LSB of BS colour code
|
|
*/
|
|
|
|
static int rach_apply_bsic(ubit_t *d, uint8_t bsic)
|
|
{
|
|
int i;
|
|
|
|
/* Apply it */
|
|
for (i=0; i<6; i++)
|
|
d[8+i] ^= ((bsic >> (5-i)) & 1);
|
|
|
|
return 0;
|
|
}
|
|
|
|
int rach_decode(uint8_t *ra, sbit_t *burst, uint8_t bsic)
|
|
{
|
|
ubit_t conv[14];
|
|
int rv;
|
|
|
|
osmo_conv_decode(&gsm0503_conv_rach, burst, conv);
|
|
|
|
rach_apply_bsic(conv, bsic);
|
|
|
|
rv = osmo_crc8gen_check_bits(&gsm0503_rach_crc6, conv, 8, conv+8);
|
|
if (rv)
|
|
return -1;
|
|
|
|
osmo_ubit2pbit_ext(ra, 0, conv, 0, 8, 1);
|
|
|
|
return 0;
|
|
}
|
|
|
|
int rach_encode(ubit_t *burst, uint8_t *ra, uint8_t bsic)
|
|
{
|
|
ubit_t conv[14];
|
|
|
|
osmo_pbit2ubit_ext(conv, 0, ra, 0, 8, 1);
|
|
|
|
osmo_crc8gen_set_bits(&gsm0503_rach_crc6, conv, 8, conv+8);
|
|
|
|
rach_apply_bsic(conv, bsic);
|
|
|
|
osmo_conv_encode(&gsm0503_conv_rach, conv, burst);
|
|
|
|
return 0;
|
|
}
|
|
|
|
|
|
/*
|
|
* GSM SCH transcoding
|
|
*/
|
|
|
|
int sch_decode(uint8_t *sb_info, sbit_t *burst)
|
|
{
|
|
ubit_t conv[35];
|
|
int rv;
|
|
|
|
osmo_conv_decode(&gsm0503_conv_sch, burst, conv);
|
|
|
|
rv = osmo_crc16gen_check_bits(&gsm0503_sch_crc10, conv, 25, conv+25);
|
|
if (rv)
|
|
return -1;
|
|
|
|
osmo_ubit2pbit_ext(sb_info, 0, conv, 0, 25, 1);
|
|
|
|
return 0;
|
|
}
|
|
|
|
int sch_encode(ubit_t *burst, uint8_t *sb_info)
|
|
{
|
|
ubit_t conv[35];
|
|
|
|
osmo_pbit2ubit_ext(conv, 0, sb_info, 0, 25, 1);
|
|
|
|
osmo_crc16gen_set_bits(&gsm0503_sch_crc10, conv, 25, conv+25);
|
|
|
|
osmo_conv_encode(&gsm0503_conv_sch, conv, burst);
|
|
|
|
return 0;
|
|
}
|
|
|