Commit Graph

6 Commits

Author SHA1 Message Date
Vadim Yanitskiy cc4213e927 coding: add gsm0503_detect_a[fh]s_dtx_frame2()
The new functions accept an additional mode_id poiner, which is
currently set for the following frames: AFS_ONSET, AHS_ONSET,
AHS_SID_FIRST_P2 with N * 16 - M bit pattern.

Also, the new API accepts soft-bits instead of hard-bits.
Converting bits from soft to hard is now performed internally.

Change-Id: Ibcac395f800bb64150c97fcdaca3523ecfc5fcee
Related: OS#5570
2022-05-27 08:31:30 +00:00
Philipp Maier 898c9c6af8 dtx: add decoding for AMR-DTX frames
gsm0503_coding contains AMR decoder functions for HR and FR. Those can
only decode AMR payload frames but not amr DTX frames. Lets add
functionality to detect DTX frames. Also lets add decoding for SID_UPDATE
frames as well as error checking for the SID frame recognition patterns.

Related: OS#2978
Change-Id: I2bbdb39ea20461ca08b2e6f1a33532cb55cd5195
2020-04-14 13:22:44 +00:00
Philipp Maier 1c46d19e43 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
2020-03-09 13:40:27 +01:00
Harald Welte 6950b191e8 coding: Add BER-reporting RACH decode functions
For all other decode operations we report the BER, but not for the
RACH.  This results in osmo-bts-trx not being able to report BER
to the higher layers, which is possible on other BTS backends.

Let's close this gap by introducing gsm0503_rach_ext_decode_ber()
and gsm0503_rach_decode_ber() with the usual n_errors / n_bits_total
arguments.

Change-Id: I2b1926a37bde860dcfeb0d613eb55a71271928c5
2018-02-26 12:26:38 +01:00
Max 32e5641dbb Add functions for extended RACH coding
Add support for extended RACH (11 bit) according 3GPP TS 45.003 §5.3.2:

* convolutional code with puncturing
* encoding/decoding routines
* corresponding tests

Change-Id: I85a34a82d5cd39a594ee89d91a2338226066ab5d
Related: OS#1548
2017-12-11 10:36:47 +00:00
Vadim Yanitskiy 3262f820b5 libosmocoding: migrate transcoding routines from OsmoBTS
There are some projects, such as GR-GSM and OsmocomBB, which would
benefit from using one shared implementation of GSM 05.03 code. So,
this commit introduces a new sub-library called libosmocoding, which
(for now) provides GSM, GPRS and EDGE transcoding routines, migrated
from OsmoBTS.

The original GSM 05.03 code from OsmoBTS was relicensed under
GPLv2-or-later with permission of copyright holders (Andreas Eversberg,
Alexander Chemeris and Tom Tsou).

The following data types are currently supported:

 - xCCH
 - PDTCH (CS 1-4 and MCS 1-9)
 - TCH/FR
 - TCH/HR
 - TCH/AFS
 - RCH/AHS
 - RACH
 - SCH

Change-Id: I0c3256b87686d878e4e716d12393cad5924fdfa1
2017-03-07 01:06:38 +07:00