diff options
| author | Philipp Maier <pmaier@sysmocom.de> | 2020-02-28 14:23:55 +0100 |
|---|---|---|
| committer | Philipp Maier <pmaier@sysmocom.de> | 2020-03-09 13:40:27 +0100 |
| commit | 1c46d19e4316ffd898d505559b2af90e6b930e27 (patch) | |
| tree | 492d7ec2d3ee3c53b0d110c78e149d0a869e58e6 | |
| parent | d8c74b81f9a1fa8a89d2e7b1a3e5cd31a9090ca3 (diff) | |
parity: add amr crc14 definition
AMR not only specifies a 6 bit CRC for regular voice information. It also
specifies a 14 bit CRC to protect the comfort noise updates contained in
the SID_UPDATE frames.
Change-Id: I5cfd8ca806aba8d42cb9787f69605cea7de6e900
Related: OS#2978
| -rw-r--r-- | include/osmocom/coding/gsm0503_parity.h | 1 | ||||
| -rw-r--r-- | src/coding/gsm0503_parity.c | 11 | ||||
| -rw-r--r-- | src/coding/libosmocoding.map | 1 |
3 files changed, 13 insertions, 0 deletions
diff --git a/include/osmocom/coding/gsm0503_parity.h b/include/osmocom/coding/gsm0503_parity.h index 28a54443..c35477f3 100644 --- a/include/osmocom/coding/gsm0503_parity.h +++ b/include/osmocom/coding/gsm0503_parity.h @@ -19,5 +19,6 @@ const struct osmo_crc16gen_code gsm0503_sch_crc10; const struct osmo_crc8gen_code gsm0503_tch_fr_crc3; const struct osmo_crc8gen_code gsm0503_tch_efr_crc8; const struct osmo_crc8gen_code gsm0503_amr_crc6; +const struct osmo_crc16gen_code gsm0503_amr_crc14; /*! @} */ diff --git a/src/coding/gsm0503_parity.c b/src/coding/gsm0503_parity.c index 874114ff..a8daacc7 100644 --- a/src/coding/gsm0503_parity.c +++ b/src/coding/gsm0503_parity.c @@ -134,4 +134,15 @@ const struct osmo_crc8gen_code gsm0503_amr_crc6 = { .remainder = 0x3f, }; +/*! GSM AMR parity (SID_UPDATE) + * + * g(x) = x^14 + x^13 + x^5 + x^3 + x^2 + 1 + */ +const struct osmo_crc16gen_code gsm0503_amr_crc14 = { + .bits = 14, + .poly = 0x202d, + .init = 0x0000, + .remainder = 0x3fff, +}; + /*! @} */ diff --git a/src/coding/libosmocoding.map b/src/coding/libosmocoding.map index 87b38864..7f88111f 100644 --- a/src/coding/libosmocoding.map +++ b/src/coding/libosmocoding.map @@ -56,6 +56,7 @@ gsm0503_sch_crc10; gsm0503_tch_fr_crc3; gsm0503_tch_efr_crc8; gsm0503_amr_crc6; +gsm0503_amr_crc14; gsm0503_xcch_burst_unmap; gsm0503_xcch_burst_map; |