See 3GPP TS 45.003 section 3.6. This channel mode is a bit special,
because unlike the other CSD specific channel modes it's interleaved
over 8 (not 22!) consecutive bursts, just like TCH/FS.
Change-Id: I4685376c8deb04db670684c9ebf685ad6fc989fa
Related: OS#1572
Currently FACCH/[FH] encoding and decoding is implemented as part of
the gsm0503_tch_[fh]r_{en,de}code and gsm0503_tch_a[fh]s_{en,de}code
API. This works fine for speech because one FACCH frame completely
replaces one or two speech frames, but this is not the case for CSD.
According to 3GPP TS 45.002, sections 4.2.5 and 4.3.5, for TCH data
channels FACCH does not replace data frames but disturbs some amount
of bits from them. Therefore we need to be able to perform FACCH
encoding and decoding independently from CSD specific coding API.
Change-Id: I0c7a9c180dcafe64e6aebe53518d3d11e1f29886
Related: OS#1572
Implement all CSD specific channel modes, except TCH/F2.4. All of
these modes are more or less similar to each other. The TCH/F2.4
is more similar to TCH/FS and slightly more complicated.
FACCH/F and FACCH/H will be implemented in a follow-up change.
Change-Id: Ib482817b5f6a4e3c7299f6e0b3841143b60fc93d
Related: OS#1572
In commit 57a3b3a51f I added new function gsm0503_tch_hr_decode2(),
but I forgot to add it to libosmocoding.map - and without the latter,
osmo-bts-trx and other applications can't use the new function.
Fix that omission.
Related: OS#5688
Change-Id: I6e75ca95409b5c368e8e04d0e0aba41e0331d9e6
This patch adds the [de]interleaving for CSD (circuit switched data),
nominally for TCH/F 9.6, but the same is also used for TCH/F 4.8,
TCH/H 4.8, TCH/F 2.4 and TCH/F 14.4.
Related: OS#4396, OS#1572
Change-Id: I6b16c2d0d7febf3883da662b2c7fec543335de12
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
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
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
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
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
Vadim Yanitskiy
Mychaela N. Falconia
Harald Welte
Philipp Maier