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coding: fix wrong n_bits_total reported for PDTCH CS2 and CS3 

In gsm0503_pdtch_decode(), we decode CS2 and CS3 as if no puncturing
was employed, reordering the coded bits and setting punctured ones
to 0 manually.  Because of that, osmo_conv_decode_ber_punctured()
reports n_bits_total higher than we actually receive over the air.

Change-Id: I6b20cc450f25c48175a61da02644d66c08e22ece
Related: OS#6342, OS#6200
This commit is contained in:
Vadim Yanitskiy 2024-01-31 22:48:32 +07:00
parent 6c4be02962
commit 3f4c6a8fbe
2 changed files with 16 additions and 7 deletions
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15
src/coding/gsm0503_coding.c
View File

@ -1059,6 +1059,7 @@ int gsm0503_pdtch_decode(uint8_t *l2_data, const sbit_t *bursts, uint8_t *usf_p,
return 23;
case 2:
/* reorder, set punctured bits to 0 (unknown state) */
for (i = 587, j = 455; i >= 0; i--) {
if (!gsm0503_puncture_cs2[i])
cB[i] = cB[j--];
@ -1066,10 +1067,13 @@ int gsm0503_pdtch_decode(uint8_t *l2_data, const sbit_t *bursts, uint8_t *usf_p,
cB[i] = 0;
}
/* decode as if puncturing was not employed (note '_np') */
osmo_conv_decode_ber_punctured(&gsm0503_cs2_np, cB, conv,
n_errors, n_bits_total,
n_errors, NULL,
gsm0503_puncture_cs2);
/* indicate the actual amount of coded bits (excluding punctured ones) */
if (n_bits_total != NULL)
*n_bits_total = 456;
/* 5.1.2.2 a) the three USF bits d(0),d(1),d(2) are precoded into six bits */
for (i = 0; i < 8; i++) {
@ -1097,6 +1101,7 @@ int gsm0503_pdtch_decode(uint8_t *l2_data, const sbit_t *bursts, uint8_t *usf_p,
return 34;
case 3:
/* reorder, set punctured bits to 0 (unknown state) */
for (i = 675, j = 455; i >= 0; i--) {
if (!gsm0503_puncture_cs3[i])
cB[i] = cB[j--];
@ -1104,9 +1109,13 @@ int gsm0503_pdtch_decode(uint8_t *l2_data, const sbit_t *bursts, uint8_t *usf_p,
cB[i] = 0;
}
/* decode as if puncturing was not employed (note '_np') */
osmo_conv_decode_ber_punctured(&gsm0503_cs3_np, cB, conv,
n_errors, n_bits_total,
n_errors, NULL,
gsm0503_puncture_cs3);
/* indicate the actual amount of coded bits (excluding punctured ones) */
if (n_bits_total != NULL)
*n_bits_total = 456;
/* 5.1.3.2 a) the three USF bits d(0),d(1),d(2) are precoded into six bits */
for (i = 0; i < 8; i++) {

8
tests/coding/coding_test.ok
View File

@ -270,7 +270,7 @@ S-Bits:
7f 7f 7f 81 7f 81 81 81 81 81 81 81 81 81 7f 7f 7f 7f 7f 81 81 81 81 7f 81 81 7f 7f 7f 7f 7f 81 81 7f 7f 7f 7f 7f 7f 81 7f 7f 81 81 7f 7f 7f 81 81 7f 81 7f 7f 7f 81 81 7f 81 7f 7f 81 81 7f 81 7f 7f 81 81 7f 81 7f 7f 81 7f 7f 81 7f 81 81 7f 7f 7f 7f 7f 81 7f 81 7f 7f 7f 7f 81 81 7f 7f 81 81 7f 7f 7f 7f 81 81 7f 81 81 7f 81 81 7f 7f 81 81 7f 81 81
7f 81 81 81 81 7f 81 7f 7f 7f 81 81 7f 7f 7f 7f 81 81 81 7f 7f 7f 81 7f 81 7f 7f 7f 81 81 81 7f 81 81 81 7f 7f 7f 81 81 81 7f 81 81 7f 81 81 7f 7f 81 81 7f 81 81 81 81 81 7f 7f 7f 7f 7f 81 81 81 81 7f 7f 7f 81 81 81 7f 7f 7f 81 81 7f 81 7f 7f 7f 81 81 7f 81 81 81 7f 7f 81 7f 81 81 81 7f 81 81 81 81 81 7f 81 7f 81 81 81 81 81 7f 81 81 7f 7f 81 81
Decoded: a3 af 5f c6 36 43 44 ab d9 6d 7d 62 24 c9 d2 92 fa 27 5d 71 7a 59 a8 42 a3 af 5f c6 36 43 44 ab a3 2f
pdtch_decode: n_errors=0 n_bits_total=588 ber=0.00
pdtch_decode: n_errors=0 n_bits_total=456 ber=0.00
Encoding: a3 af 5f c6 36 43 44 ab d9 6d 7d 62 24 c9 d2 92 fa 27 5d 71 7a 59 a8 42 a3 af 5f c6 36 43 44 ab a3 af 5f c6 36 43 44 03
U-Bits:
@ -284,7 +284,7 @@ S-Bits:
81 81 7f 7f 7f 81 81 7f 7f 7f 7f 7f 7f 7f 81 7f 7f 7f 7f 81 7f 81 7f 81 7f 81 81 81 81 81 81 7f 81 7f 81 81 7f 7f 7f 81 81 81 7f 81 7f 81 81 81 81 81 7f 7f 81 81 81 81 7f 7f 7f 81 7f 7f 7f 7f 81 81 7f 81 81 7f 7f 7f 81 81 7f 7f 81 81 7f 81 81 7f 7f 81 81 7f 81 81 7f 7f 7f 7f 81 7f 81 7f 7f 7f 7f 7f 81 7f 7f 7f 7f 7f 81 7f 81 81 7f 7f 81 81 81 7f
7f 81 81 81 7f 7f 7f 7f 81 7f 81 7f 7f 7f 7f 81 7f 7f 81 7f 7f 81 7f 81 7f 7f 81 7f 7f 7f 81 7f 7f 81 81 7f 81 7f 7f 81 81 81 7f 81 7f 7f 7f 7f 81 7f 81 81 81 7f 7f 7f 7f 7f 81 81 81 81 81 7f 7f 81 81 7f 7f 7f 7f 7f 81 81 7f 7f 81 7f 7f 81 81 7f 81 81 81 7f 81 7f 7f 81 81 81 81 7f 81 7f 7f 81 7f 81 7f 7f 81 81 81 81 7f 81 7f 7f 81 81 7f 7f 81 81
Decoded: a3 af 5f c6 36 43 44 ab d9 6d 7d 62 24 c9 d2 92 fa 27 5d 71 7a 59 a8 42 a3 af 5f c6 36 43 44 ab a3 af 5f c6 36 43 44 03
pdtch_decode: n_errors=0 n_bits_total=676 ber=0.00
pdtch_decode: n_errors=0 n_bits_total=456 ber=0.00
Encoding: a3 af 5f c6 36 43 44 ab d9 6d 7d 62 24 c9 d2 92 fa 27 5d 71 7a 59 a8 42 a3 af 5f c6 36 43 44 ab a3 af 5f c6 36 43 44 ab d9 6d 7d 62 24 c9 d2 92 fa 27 5d 71 7a 28
U-Bits:
@ -326,7 +326,7 @@ S-Bits:
7f 7f 81 7f 81 81 7f 7f 7f 81 7f 7f 7f 81 81 7f 81 7f 81 7f 7f 7f 7f 7f 81 7f 81 81 81 7f 81 7f 7f 7f 81 7f 7f 81 7f 7f 81 7f 7f 7f 81 7f 81 81 81 81 7f 81 7f 81 7f 7f 81 81 7f 7f 7f 7f 81 81 7f 7f 7f 7f 7f 81 81 7f 7f 7f 81 7f 7f 7f 81 81 7f 7f 7f 81 7f 7f 81 7f 81 7f 7f 7f 81 7f 7f 7f 7f 81 7f 7f 7f 7f 7f 7f 81 7f 7f 81 7f 81 7f 7f 81 7f 81 81
81 7f 81 7f 7f 81 7f 7f 81 81 7f 7f 81 7f 81 7f 7f 81 81 81 7f 81 7f 81 81 7f 81 7f 81 7f 81 7f 81 7f 7f 7f 7f 7f 7f 81 81 7f 81 7f 7f 7f 81 7f 7f 7f 7f 7f 81 7f 81 7f 81 7f 7f 7f 81 7f 81 7f 7f 81 7f 81 81 81 7f 7f 81 7f 7f 7f 81 7f 7f 7f 7f 81 81 7f 81 81 81 7f 7f 7f 81 7f 7f 7f 7f 81 81 81 7f 7f 7f 7f 81 7f 7f 81 7f 81 7f 7f 81 81 7f 7f 81 7f
Decoded: 01 02 03 04 05 06 07 08 09 0a 0b 0c 0d 0e 0f 10 11 12 13 14 15 16 17 00 00 00 00 00 00 00 00 00 00 00
pdtch_decode: n_errors=0 n_bits_total=588 ber=0.00
pdtch_decode: n_errors=0 n_bits_total=456 ber=0.00
Encoding: 01 02 03 04 05 06 07 08 09 0a 0b 0c 0d 0e 0f 10 11 12 13 14 15 16 17 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
U-Bits:
@ -340,7 +340,7 @@ S-Bits:
81 7f 81 7f 81 81 7f 7f 7f 81 7f 81 7f 7f 81 7f 7f 7f 81 7f 7f 81 7f 7f 7f 7f 81 7f 7f 7f 7f 7f 81 81 7f 7f 7f 7f 7f 81 81 81 7f 7f 7f 7f 81 81 7f 81 7f 7f 7f 7f 7f 81 7f 7f 7f 7f 81 7f 81 81 7f 7f 7f 81 7f 81 81 7f 81 7f 7f 7f 81 7f 7f 7f 7f 81 7f 7f 7f 81 7f 7f 81 7f 7f 7f 7f 81 7f 81 7f 81 7f 7f 81 7f 81 7f 7f 7f 7f 7f 7f 7f 7f 81 81 81 7f 7f
7f 7f 81 7f 7f 7f 7f 81 7f 81 7f 7f 81 7f 7f 7f 7f 81 7f 81 7f 7f 7f 81 7f 7f 81 7f 7f 7f 81 81 7f 81 7f 7f 7f 81 7f 81 7f 7f 7f 7f 81 81 7f 81 7f 81 7f 7f 81 7f 81 7f 81 7f 81 7f 7f 7f 7f 7f 7f 81 7f 81 81 81 81 7f 7f 7f 7f 7f 7f 81 7f 7f 7f 81 81 7f 81 7f 81 7f 7f 7f 81 7f 7f 81 7f 81 81 7f 81 7f 81 7f 7f 7f 7f 81 7f 7f 7f 81 81 81 81 7f 7f 7f
Decoded: 01 02 03 04 05 06 07 08 09 0a 0b 0c 0d 0e 0f 10 11 12 13 14 15 16 17 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
pdtch_decode: n_errors=0 n_bits_total=676 ber=0.00
pdtch_decode: n_errors=0 n_bits_total=456 ber=0.00
Encoding: 01 02 03 04 05 06 07 08 09 0a 0b 0c 0d 0e 0f 10 11 12 13 14 15 16 17 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
U-Bits: