The logic responsible for enabling and disabling the loop appears
to be broken: during my experiments trx_loop_amr_set() was never
called with loop=1. It's not clear what's the motivation behind
this breaker, so I propose to rip it out for now. This patch
finally makes the loop work (confirmed with a TEMS phone).
Related: SYS#5917, OS#4984
Change-Id: I09b649973d4269c4082a4fafa493c37825f95a9c
(cherry picked from commit 541b7525ae)
This reverts commit 1f9fbd8816, which
was a workaround rather than a proper fix. The root problem has
been fixed in libosmocoding [1], so ~50% BER is not the case for
AFS_SID_UPDATE frames anymore.
Related: I813081a4c0865958eee2496fe251ae17235ac842 (libosmocore.git)
Change-Id: Iebe139632daf1d1f72e39fe9d1497059f68625b9
We have two similar values in enum gsm0503_amr_dtx_frames:
* AFS_SID_UPDATE - precursor of SID UPDATE,
* AFS_SID_UPDATE_CN - the actual SID UPDATE.
The former is internally used by libosmocoding to mark the current
frame as a precursor of the actual SID UPDATE frame - the later.
+---+---+---+---+---+---+---+---+
| _ | _ | _ | _ | a | b | c | d | AFS_SID_UPDATE
+---+---+---+---+---+---+---+---+
| a | b | c | d | _ | _ | _ | _ | AFS_SID_UPDATE_CN
+---+---+---+---+---+---+---+---+
^
|
| We're here.
Do not treat the precursor frames as a SUB frames, as they contain
no information (rc=-1) and usually have *expected* BER ~50%. This
fixes unexpected RXQUAL-SUB > 0 in the Uplink measurements during DTX.
Change-Id: I46f32bbbcb6284615d05b8703945c5ca4da55b92
Related: SYS#5853
Attempting to detect missing Uplink frames in the *Downlink* path
is an ugly hack, that was needed before we had proper per-lchan
detection of missing bursts and NOPE indications in TRXDv1.
* [1] per-lchan detection of missing bursts was fixed in Aug 2018.
* [2] TRXDv1 support was introduced in Jul 2019.
Today is 2022 and it makes no sense to keep this hack. Even if
the transceiver does not support TRXDv1, per-lchan detection
will compensate the missing Uplink bursts.
Change-Id: Ic292d180ba64206fb4d88adb284f9f9d058b4587
Related: [1] I70d05b67a35ddcbdd1b6394dbd7198404a440e76
Related: [2] If61c71d20d590bf07bfd019afb33000a0b6135bd
I did not realize with my previous patch that there's a common place
where features available for all backends should be enabled. So move it
there.
Related: SYS#5922, OS#5538
Change-Id: Id688ddae5cd714355fcc5324f33c9397fecae261
According to osmo-bsc I0e80ca5afc06737273b6699bde6e325e454b57f6, the
PAGING_COORDINATION feature should be well supported in osmo-bts. Adjust
the bts_model_init functions to report this to the BSC, so it properly
sets this in SI13 and so we can avoid this notice in the log:
Get Attributes Response: reported feature 'PAGING_COORDINATION' is not supported, while we thought it is.
Related: SYS#5922, OS#5538
Change-Id: Ib06829501f4221a7f7b0344ec7991ceba74e7641
Currently (without this patch) if tch_dl_dequeue() yields nothing we're
scheduling dummy FACCH/H *regardless* if it's permitted to start at the
given TDMA FN or not. This may result in misaligned FACCH transmission,
so the MS will not able to decode anything and will report BER>0.
With this patch applied we schedule FACCH/H if it's allowed to start
at the current TDMA FN; otherwise send half-filled bursts with even
numbered bits contaning 232 encoded bits of the previous L2 frame
and 232 odd numbered bits all set to 0.
This patch does not guard against sporadic gaps in the Downlink TCH
queue. However when tch_dl_dequeue() constantly yields nothing, e.g.
when we end up with a codec mismatch, then this additional check saves
us from starting misaligned FACCH/H transmission. If we start at a wrong
TDMA offset, then all subsequent FACCH frames will be scheduled at wrong
offsets and thus none of them will be decoded by the MS.
Change-Id: I6f8af140a6ccf3d5fd7b98f6cb5c18e2c5e2f61b
Related: SYS#5919, OS#4823
* dl_ongoing_facch must be set for correct FACCH/H scheduling;
* dl_facch_bursts must be set for FACCH overpower to work.
Change-Id: Ief12eb67ad80de3b71f5226858dc2e0c8ae76948
Related: SYS#5919, OS#4823
If set, chan_state->dl_ongoing_facch indicates that we're sending
the 2 (out of 6) middle bursts of FACCH/H. In this case there is
no room for encoding an additional frame, because both even and
odd numbered bits are occupied by a previously encoded FACCH/H.
Right after calling tch_dl_dequeue():
* do not check the dequeued message against NULL,
* do not compare the message length to GSM_MACBLOCK_LEN,
* immediately free() it and jump to the sending part.
Change-Id: Ib923b8f5cc1063e9fc18acd2bdd003fd09f4b70f
Related: SYS#5919, OS#4823
Unlike SACCH, FACCH has no dedicated slots on the multiframe layout.
It's multiplexed together with TCH (speech or data) frames basically
by replacing (stealing) them. This is common for both TCH/F and
TCH/H, with the only difference that FACCH/H steals two TCH frames
(not just one) due to a longer interleaving period.
Let's implement the multiplexing in the common function, which is
used to dequeue to be transmitted frames - this slightly reduces
code duplication. Use a new name, so that it's clear what it does.
Change-Id: I9822b1a17185d5487f0f6d3ed0203e806c053d7d
Related: SYS#5919, OS#4823
Manual analysis of code didn't end up in finding any issue, so this
seems a false positive (I can really understand gcc failing to do proper
job here, this function has way to many jumps here and there.
"""
/sched_lchan_tchh.c:88:13: error: ‘rc’ may be used uninitialized in this function [-Werror=maybe-uninitialized]
88 | int rc, amr = 0;
| ^~
"""
Change-Id: Ifebaee63a9dad04976ffb4438c32360687ef095a
Keep collecting C/I samples even if the MS has not yet applied
previously requested codec mode. The C/I ratio is expected to
stay more or less the same, no matter which codec mode is used.
Change-Id: Ieb5473ead7200f652b5d0e339e4e252d6567482d
Related: SYS#5917, OS#4984
With the current implementation the AMR loop is unable to upgrade
the current codec mode unless it reaches the worst possible value.
The problem is in the 'else' statement connection both 'if's.
Change-Id: I4c0fb28813373c3d4addd28c66f5136d2c4f9ed8
Related: SYS#5917, OS#4984
Currently we're logging AMR mode *indexes*, not the actual modes.
Let's make it cleaner for the user by logging both mode and index.
Change-Id: I4feb3a3823799a290a50a48275e45f3331874d1a
Related: SYS#5917, OS#4984
Looks like this structure was copied from openbsc/osmo-bsc as-is.
The ms_mode[] makes no sense in the context of BTS, so remove it
and rename bts_mode[] to mode[] for the sake of brevity.
Change-Id: I7442360ed857554440a0b9854f2d2bbab9dc5a71
Related: SYS#5917, OS#4984
There is nothing else except the AMR link adaptation loop in these files.
Change-Id: Iff2c0d32da5cd89824197d05f4732ce974c12f28
Related: SYS#5917, OS#4984
This check is redundant because it's guaranteed in rts_tchh_fn()
that FACCH/H is always scheduled at the correct frame offset.
Change-Id: I2f0c26f6007455aa1e3e8b27bc9d173f6b1f8c38
Related: SYS#5916, OS#5518
Since change [1], in rts_tchh_fn() we're using a lookup table for
DL FACCH/H. Let's do the same for UL FACCH/H in rx_tchh_fn().
Change-Id: I7c4e3befdd33bef4d89a04a4c7cb1a2d4078c156
Related: [1] I3dba243e5a1b7c8008ef0178ea18ed885256c50d
Related: SYS#5916, OS#5518
In change [1] I didn't take into account that the TCH/H burst buffer
is 6 bursts wide, and that we're decoding 2 bursts late:
+---+---+---+---+---+---+
| a | b | c | d | e | f | Burst 'a' received first, 'f' last
+---+---+---+---+---+---+
^^^^^^^^^^^^^^^ Speech frame (bursts 'a' .. 'd')
^^^^^^^^^^^^^^^^^^^^^^^ FACCH frame (bursts 'a' .. 'f')
The lookup table for TCH/H was calculated with the assumption that
in rx_tchh_fn() the 'bi->fn' indicates TDMA frame number for burst
'd', but in reality it holds the frame number of burst 'f'.
Change-Id: I4f22cf49fd52ed26f8017f76461059a701c181e1
Fixes: [1] I46def864729c8f9063af201750456771ea5558d5
Related: SYS#5916
It makes no sense to have these tables in the header file, because
they're not used anywhere outside of the respective lchan handlers.
Change-Id: Ibdebfb9b1ef78c960b08240ebdb4c7af92cbed11
Related: SYS#5916
In change [1] I broke measurement reporting for TCH/H in signalling
mode. The problem is that in rx_tchh_fn() we started to invalidate
the Uplink RSSI for FACCH regardless of the channel mode: speech or
signalling. In speech mode, the averaged measurements are carried
over by the two BFIs. In signalling mode we send no BFIs, so:
* let's use the proper averaging mode S6N6 (not S6N4), and
* send the averaged measurements together with the FACCH.
This change fixes BTS_Tests.TC_meas_res_sign_tchh[_toa256].
Change-Id: If98aa1f0f7255f20344460bdd07e2c896dd6e56f
Fixes: [1] I7902b4709bc3f418174e8373f52e87bb31cdc826
Related: SYS#5853
There is no reason not to use 'chan_state->tch_mode' directly in
the 'switch' statement. If a logical channel is in signalling
mode, then both 'chan_state->{rsl,tch}_cmode' are set to
RSL_CMOD_SPD_SIGN and GSM48_CMODE_SIGN, respectively.
Change-Id: I9e5e2c891c80c32fc522b53c9371b71ea32dd54d
Related: SYS#5853
3GPP TS 45.009 defines that Codec Mode Indications shall be sent
with speech frames having specific TDMA frame numbers of their
*first* bursts, which are defined in tables 3.2.1.3-{1,2,3,4}.
Performance-wise it's batter to have these tables implemented as
arrays, rather then using the 'switch' statement. We can simplify
things even further and have TDMA frame numbers corresponding to
the *last* bursts in them. This eliminates the need of doing an
additional last-to-first mapping, so that bi->fn can be used.
Change-Id: I46def864729c8f9063af201750456771ea5558d5
Once we have an Uplink speech or FACCH frame decoded, we need to
hand it over to the upper layers indicating TDMA frame number of
the *first* burst corresponding to the beginning of a block.
Currently we use libosmogsm's gsm0502_fn_remap() API to calculate
the first TDMA frame number from the given last frame number.
This API involves iterating over the pre-calculated offset tables
for different channel and payload types, and thus imposes some
additional CPU cycles. Another downside of the current approach
is that we have to perform such lookups several times for each
decoded L2 frame, e.g. for FACCH on TCH/AHS we do it three times!
In this patch I propose an alternative approach of storing TDMA
frame numbers in the measurement history, together with the
associated samples. This way we can easily get N-th frame number
from there without performing any additional computations, other
than what we already do during the measurement processing.
Change-Id: Id9a2b7b0f1a1ad7cfbbab862faf521e135c90605
The idea of this change is to avoid attempting to decode the burst
buffer unless it's filled up completely. This eliminates expected
decoding errors in the beginning of lchan's lifetime. Moreover
this allows us to be sure that the measurement history is complete,
so that we can abuse it to store TDMA frame numbers later.
Note that even in the absence of NOPE indications (TRXDv0 case)
we can still be sure that the burst mask has no gaps due to lost
bursts, because they are compensated by trx_sched_calc_frame_loss().
Change-Id: I56bebe1374eb803e3c1e9f08dda4da50a074ab0b
For both TCH/F and TCH/H, the receive burst buffer needs to be
periodically shifted leftwards due to the nature of block-diagonal
interleaving. Currently we do this on receipt of bid=3 for TCH/F
and bid=1 for TCH/H, right after attempting to decode the buffer.
If for some reason we return early before attempting to decode the
buffer, the content of that buffer might not be shifted and some
bursts might be overwritten. This can be easily avoided by doing
the shifting on receipt of bid=0 for both TCH/H and TCH/F.
Change-Id: I0bd69f5a8f5c665fb5f00c127bc3fe1d91167abb
In the current implementation of both TCH/F and TCH/H lchans, we
set the 'bfi_flag' to true only if decoding fails. Perhaps this
was not the case when I wrote [1], so using meas_avg might result
in using uninitialized memory. This is not the case anymore.
Pass the *averaged* measurememnts regardless of decoding result.
Change-Id: I23f767364a018d30d04885990adf69b50b2c9738
Related: [1] I2b02b51fea5664f161382a4ddc63dbf14ffc9ac5
FACCH/H takes out two speech frames, so we send two BFIs once we
have received it in rx_tchh_fn(). The upper layers responsible
for handling of the Uplink measurements expect a fixed amount of
measurement samples, so currently we do:
* send a FACCH frame with the associated measurememnts (S6N6),
* send the 1st BFI with invalidated measurements (RSSI=0),
* send the 2nd BFI with the stored measurememnts of FACCH.
This is achieved by preserving a copy of the FACCH measurememnts
in chan_state->meas_avg_facch and then using it two bursts later.
The same goal can be achieved a lot easier by sending the associated
measurements with both BFIs as if no FACCH was received:
* send a FACCH frame with invalidated measurememnts (RSSI=0),
* send the 1st BFI with the associated measurememnts (S6N4),
* send the 2nd BFI with the associated measurememnts (S6N4).
This eliminates the need to store anything outside of the existing
measurement history and simplifies the code a lot. Also, this
eliminates the need for using a dedicated averaging mode S6N6.
Varified by running BTS_Tests.TC_meas_res_speech_tchh_facch.
Change-Id: I7902b4709bc3f418174e8373f52e87bb31cdc826
Related: I1ad9fa3815feb2b4da608ab7df716a87ba1f2f91
It makes no sense to store BER10k value of an Uplink FACCH frame
in order to indicate it in a BFI later on. Given that these BFIs
are generated artificially, it's fine to indicate BER10k=0.
Change-Id: I24d12892760dca0ad0a5c2abca9fc66523d9e614
Related: I1ad9fa3815feb2b4da608ab7df716a87ba1f2f91
Both TRXC_RACH and TRXC_PTCCH are handled in the rx_rach_fn(),
so we can eliminate the need of having a 'switch' statement in
the general (perfrmance critical) code path.
Change-Id: I66d8785a63215af37a77e258039549e4e6292e49
Compared to TCH/F, TCH/H is a bit special in a way that:
* speech frames are interleaved over 4 consecutive bursts,
* while FACCH frames are interleaved over 6 consecutive bursts.
This is why in rx_tchh_fn() we allocate a buffer large enough to
store up to 6 bursts. Let's say we have that buffer filled up
completely with all 6 bursts (from 'a' to 'f'). Now attempting
to decode them may yield either a speech frame or a FACCH frame:
+---+---+---+---+---+---+
| a | b | c | d | e | f | Burst 'a' received first, 'f' last
+---+---+---+---+---+---+
^^^^^^^^^^^^^^^ Speech frame (bursts 'a' .. 'd')
^^^^^^^^^^^^^^^^^^^^^^^ FACCH frame (bursts 'a' .. 'f')
For FACCH we use measurement averaging mode SCHED_MEAS_AVG_M_S6N6,
so that 6 last samples are averaged - so far so good. For speech
we use SCHED_MEAS_AVG_M_S4N4, so that 4 last samples corresponding
to bursts 'c', 'd', 'e', 'f' are averaged - this is wrong.
We actually need to average the *first* 4 samples corresponding to
bursts 'a', 'b', 'c', 'd' in the case of speech. Let's add and use
a new averaging mode SCHED_MEAS_AVG_M_S6N4 for that.
Change-Id: Iea6f4e5471550f4c2b57aaebeac83c80e879489d
This should be better performance-wise and would also allow to avoid
having the same switch statement duplicated in functions added later.
Change-Id: If8124dcd38e7c8408a9f3b9a574d9e3181a2eb15
This is a purely cosmetic change. The new naming clearly indicates
how deep to go back in the measurement history (S) and how many
samples to average (N). For example:
* SCHED_MEAS_AVG_M_S4N4 - go S=4 steps back and average N=4 samples;
* SCHED_MEAS_AVG_M_S6N2 - go S=6 steps back and average N=2 samples.
Change-Id: I96a8dd08084c7c179f879fc00e75c5edcfb11caa
Set the FT (Frame Type) in the ToC (Type-of-Content) section as
defined in section 5.2 of RFC 5993. Before this change SID frames
had FT = 000 (Good Speech frame), because gsm0503_tch_hr_decode()
does not distinguish between speech and SID frames internally.
Change-Id: I09cec984bb60c754908126acf0300a2cc602485c
Related: SYS#5853
According to RFC5993, which is referenced by 3GPP TS 48.103, the
complete RTP HR payload consists of a Table-of-Contents (ToC) byte
followed by the 14 bytes of the HR codec frame. See section 5.2.
gsm0503_tch_hr_decode() outputs frames in the RTP format with
length of 15 bytes (120 bits): 1 (ToC) + 14 (HR frame):
+-------------+-------------------------
| ToC section | HR codec frame ...
+-------------+-------------------------
osmo_hr_check_sid() expects a HR codec frame of 14 bytes (112 bits)
as the input, so we should skip the ToC section when calling it.
Change-Id: Ie5fa776dcb2b2203a97aed56ecbf2450af7d87c1
Related: SYS#5853
We already have BER10k calculated in the generic code path, so do
not calculate it once again in the FACCH specific branch.
Change-Id: I5d3955d09990e280d11d687385eeaf5edf437395
It makes no sense to perform the SID codeword lookup in signalling
frames (FACCH), because it can be present only in speech frames.
Change-Id: I2f8137993acfe8a8add3fc2af276e5eb4da1605e
Related: SYS#5853
This new rate counter allows to monitor the efficiency of the
radio carrier cache used for routing Downlink bursts when
baseband frequency hopping is in use.
Change-Id: Ie6da829e47298476267c8df2dcedafad564cbbb4
Related: SYS#5855
Given how often we send and receive TRXD PDUs, I believe it maks
sense to use OSMO_UNLIKELY() in the error checking conditions.
Theoretically this should improve performance.
Change-Id: I9266aaf2bbc0acfe21e9bfb12c9f38621d120553
Vadim Yanitskiy
Oliver Smith
Pau Espin