In Iec5c1f2619a82499f61cb3e5a7cd03ff0f020ad8 we added
osmo_{fr,efr}_sid_preen() functions that apply SID classification
of GSM 06.31/06.81 section 6.1.1 (osmo_{fr,efr}_sid_classify()),
reject invalid SID, and "rejuvenate" deemed-valid SID frames by
resetting their SID code word, correcting the one bit error that
may be present in a deemed-valid SID frame. However, the last
operation (rejuvenation of a SID frame by resetting its SID field)
should also be made available as its own function, as it may be
more efficient in some applications: for example, an application
may need to call osmo_{fr,efr}_sid_classify(), apply the rejuvenation
to valid SID, but also use the classification result to drive other
logic. Factor out these functions.
Change-Id: I1d6dd867a358bdda8850cd8c959d0f361c0a5b6d
Table 1 in section 6 of 3GPP TS 46.011 (FR codec, substitution and
muting of lost frames) specifies a silence frame in the form of
GSM 06.10 parameters - add a const datum to libosmocodec embodying
this GSM 06.11 silence frame in GSM-FR RTP encoding.
Related: OS#6027
Change-Id: Idf31051ea783435268944286a71d2b0ac342a4b5
Those network elements which receive a stream of codec frames that
may come from the uplink of GSM call A and which are responsible
for preparing the frame stream for the downlink of GSM call B
(OsmoMGW feeding TRAU-DL, or OsmoBTS receiving RTP and feeding DL
to its PHY) must be prepared for the possibility that their
incoming frame stream may contain corrupted SID frames, presumably
from bit errors on radio link A. Per the rules of section 6.1.1
of GSM 06.31 for FR and GSM 06.81 for EFR, SID frames with just one
errored bit are still to be accepted as valid, whereas frames with
more corrupted bits which are still recognizable as SID are classified
as invalid SID.
In the case of a TrFO call, the entity switching from leg A UL to
leg B DL is responsible for *not* transmitting invalid SID frames
on the destination leg (they should be treated like BFIs), and any
deemed-valid SID frames that are forwarded should be preened,
correcting that one bit error they may exhibit. The functions
added here provide that functionality.
Change-Id: Iec5c1f2619a82499f61cb3e5a7cd03ff0f020ad8
The existing osmo_{fr,efr}_check_sid() functions detect whether or not
the frame of bits passed to them constitutes an absolutely perfect
SID frame, with each of 95 SID code word bits set to 0 for FR or
1 for EFR. However, the rules of section 6.1.1 in GSM 06.31 & 06.81
allow up to one bit to be in error for the frame to be accepted as
valid SID, and the same rules also call out a third state (invalid SID)
in between valid SID frames and other frames that are classified as
speech. Support for these rules cannot be patched into those familiar
osmo_{fr,efr}_check_sid() functions because doing so would alter
behavior of existing programs, hence new functions need to be added.
The new functions that implement the exact rules of section 6.1.1 of
GSM 06.31 and 06.81 will need to be used if anyone needs to construct
an outgoing TRAU-UL frame (for example, as part of implementing
TS 28.062 TFO), and they are expected to be useful as part of more
sophisticated ECU implementations.
Change-Id: Ie91a52c6f04689082d8004311517d8ce0c544916
Remove the paragraph about writing to the Free Software Foundation's
mailing address. The FSF has changed addresses in the past, and may do
so again. In 2021 this is not useful, let's rather have a bit less
boilerplate at the start of source files.
Change-Id: I5050285e75cf120407a1d883e99b3c4bcae8ffd7
Let's fix some erroneous/accidential references to wrong license,
update copyright information where applicable and introduce a
SPDX-License-Identifier to all files.
Change-Id: I39af26c6aaaf5c926966391f6565fc5936be21af
Considering the various styles and implications found in the sources, edit
scores of files to follow the same API doc guidelines around the doxygen
grouping and the \file tag.
Many files now show a short description in the generated API doc that was so
far only available as C comment.
The guidelines and reasoning behind it is documented at
https://osmocom.org/projects/cellular-infrastructure/wiki/Guidelines_for_API_documentation
In some instances, remove file comments and add to the corresponding group
instead, to be shared among several files (e.g. bitvec).
Change-Id: Ifa70e77e90462b5eb2b0457c70fd25275910c72b
Especially for short descriptions, it is annoying to have to type \brief for
every single API doc.
Drop all \brief and enable the AUTOBRIEF feature of doxygen, which always takes
the first sentence of an API doc as the brief description.
Change-Id: I11a8a821b065a128108641a2a63fb5a2b1916e87
failure to do so would prevent the compiler from catching
inconsistencies between declaration and definition.
Change-Id: I88617c97adcff328292e501fd5d254eeae96a660
Based on ETSI TS 101 318 section 5.1.2 the 95 bits SID code word
is not detected correctly due to a wrongful offset in the bits
location indexes.
Change-Id: I45d98c6edf267f313883503a65385190ffbc65ca
Add functions which check if given FR or HR frame (packed in RTP)
contains SID (SIlence Descriptor) and corresponding tests.
Related: OS#22
Change-Id: I4051e3c0d4fb9ee93d7e9e0ef4abaf9f18e227ca
Reviewed-on: https://gerrit.osmocom.org/160
Tested-by: Jenkins Builder
Reviewed-by: Harald Welte <laforge@gnumonks.org>
When declaring them constant, they are written on the .rodata section
instead of .data, which means that they can be mapped directly from
disk to memory.
Signed-off-by: Diego Elio Pettenò <flameeyes@flameeyes.eu>
Mychaela N. Falconia
Oliver Smith
Harald Welte
Neels Hofmeyr
Sylvain Munaut