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
Before a massive refactoring of the scheduler structures [1] it was
impossible to have a clean hierarchy, in which the burst buffers
get allocated as children of their parent timeslot structures.
This change makes it easier to read talloc reports and simplifies
memory management, offloading free()ing of the burst bufferes to
talloc.
Change-Id: Idb1ceaf83c433d2d0eb84d77c2187a00a657905c
Related: [1] I7c4379e43a25e9d858d582a99bf6c4b65c9af481
GSM/EDGE Evolution and Performance, Section 12.3 suggests Temporary
Overpower as another solution to improve SACCH/FACCH performance in
case of bad C/I. The idea here is that you increment the DL transmit
power by 2..4dB only for FACCH/SACCH bursts, while keeping all voice
bursts at the lower (normal) level as determined by BS power control.
SACCH blocks can be recognized by the channel type, since they're
always transmitted in specific frames of a multiframe. FACCH blocks,
however, are not predictable and can substitute voice blocks at
(almost) any time. Thus we need to mark FACCH bursts as such in
the logical channel handlers (using TRX_BR_F_FACCH).
Change-Id: Ie8a626fefccf1eb07271058e5126ec106cb1abcf
Related: SYS#5319
In functions responsible for Downlink burst scheduling, it may happen
that the buffer, containing a complete set of to be transmitted bursts,
a) is not yet allocated or b) was de-allocated intentionally. In this
case, we return early to avoid NULL pointer dereference. The returned
value is then checked against 0 in _sched_dl_burst().
Returning 0 makes _sched_dl_burst() apply per-burst attenuation, as
well as the A5/x encryption (if enabled). And this makes no sense
in either of the cases mentioned above.
Moreover, in the BCCH power reduction mode, this causes some bursts
(bid > 0) of idle PDTCH/PTCCH blocks to be transmitted at full power,
breaking the energy saving feature.
Change-Id: I18aa73cc950fdfac030b63f7a434a71b4596095d
Related: SYS#4919
All generated RTP that originates from the BTS relates to uplink. When
generating AMR BAD frame RTP packets, we must use ul_cmr/ul_ft and not
dl_cmr/dl_ft.
Change-Id: Ifa009819791cf7df2dd8201f442b0dae06f622a4
Related: SYS#5549
The AMR transmission phase directly depends on the frame number. The
transmission phase is used to tell if a received AMR frame contains a
CMI (frame type that is currently used) or CMR (frame type that the
receiver should use) codec identifier. The formulas in the present
implementation seem to be correct but they do not reflect the numbers in
the spec very well, nor do they have unit-tests. Lets replace them with
more readble functions and test those functions with unit-tests.
Change-Id: I94a934a6b3b397b4cd0e9da3577325de58814335
Related: SYS#5549
CMR and FT are updated each time an AMR voice frame is received from the
radio interface. The transmission phase decides whether the voice frame
contains CMR or FT. The code follows the transmission phase and keeps
ul_cmr and ul_ft up to date.
In contrast to the AMR frames on the radio interface, an AMR RTP packet
always contains the CMR and the FT value.
When generating the RTP payloed, The present implementation uses the CMR
in the position where the FT should be and the FT is ignored. This is not
correct.
Change-Id: I6bb10ff3c76f67b9830787497653b546cf27fe8e
Related: SYS#5549
If for whatever reason the transmit queue of a TCH/{F,H} contains
neither speech frames nor signalling blocks, osmo-bts-trx would
currently transmit garbage. Of course, this causes decoding
errors at the MS side.
Ideally, we should employ an ECU (Error Concealment Unit) for the
given codec in use. However, a simpler solution is to transmit
dummy LAPDm frames over FACCH. This is what e.g. nanoBTS does.
Change-Id: I868afecbcb6890f40c8f146e3ce00e836b794dd3
Related: OS#4823
The TSC (Training Sequence Code) value in 'struct gsm_bts_trx_ts'
is always initialized in oml_rx_set_chan_attr() during the OML
bootstrapping, so there is no need for gsm_ts_tsc() - remove it.
Store the initial TSC value in 'struct gsm_bts_trx_ts', so we can
apply a different TSC value during the RSL CHANnel ACTIVation.
Store the Training Sequence Code/Set in 'struct trx_dl_burst_req'.
These values are indicated to the transceiver (TRXDv2 PDUs, 'MTS'
field) and used by the new TRX_{GMSK,8PSK}_NB_TSC macros.
Change-Id: I3744bc308b99ef941e6e9d139444e414abebc14b
Related: SYS#4895, OS#4941
Together with the 'generic' structures which used to be shared between
osmo-bsc and osmo-bts some time ago, we also have the following
osmo-bts-trx specific structures (in hierarchical order):
- struct l1sched_trx (struct gsm_bts_trx),
- struct l1sched_ts (struct gsm_bts_trx_ts),
- struct l1sched_chan_state (struct gsm_lchan).
These structures are not integrated into the tree of the generic
structures, but maintained in a _separate tree_ instead. Until
recently, only the 'l1sched_trx' had a pointer to generic
'gsm_bts_trx', so in order to find the corresponding 'gsm_lchan' for
'l1sched_chan_state' one would need to traverse all the way up to
'l1sched_trx' and then tracerse another three backwards.
+ gsm_network
|
--+ gsm_bts (0..255)
|
--+ l1sched_trx --------------------> gsm_bts_trx (0..255)
| |
--+ l1sched_trx_ts --+ gsm_bts_trx_ts (8)
| |
--+ l1sched_chan_state --+ gsm_lchan (up to 8)
I find this architecture a bit over-complicated, especially given
that 'l1sched_trx' is kind of a dummy node containing nothing else
than a pointer to 'gsm_bts_trx' and the list of 'l1sched_trx_ts'.
In this path I slightly change the architecture as follows:
+ gsm_network
|
--+ gsm_bts (0..255)
|
--+ gsm_bts_trx (0..255)
|
--+ l1sched_trx_ts <----------------> gsm_bts_trx_ts (8)
| |
--+ l1sched_chan_state --+ gsm_lchan (up to 8)
Note that unfortunately we cannot 1:1 map 'l1sched_chan_state' to
'gsm_lchan' (like we do for 'l1sched_trx_ts' and 'gsm_bts_trx_ts')
because there is no direct mapping. The former is a higl-level
representation of a logical channel, while the later represents
one specific logical channel type like FCCH, SDCCH/0 or SACCH/0.
osmo-bts-virtual re-uses the osmo-bts-trx hierarchy, so it's also
affected by this change.
Change-Id: I7c4379e43a25e9d858d582a99bf6c4b65c9af481
Historically the logical channel handlers like rx_data_fn() used to accept
quite a lot of arguments. With the introduction of additional measurement
parameters it has become clear that we need to group the arguments into
structures. This is why both 'trx_{dl,ul}_burst_{req,ind}' structures
were introduced.
However, both channel type and burst ID were kept untouched, so until
now we had them being passed between the scheduler functions here and
there. This change is a logical conclusion of the original change
mentioned above.
As a part of this change, the new LOGL1SB() macro is introduced. It
does accept a pointer to 'trx_{dl,ul}_burst_{req,ind}' and expands the
context information for the old LOGL1S() macro.
Change-Id: Ic5a02b074662b3e429bf18e05a982f3f3e7b7444
The measurement results / TCH indications that are handed when decoding
the TCH/H are off by two bursts. Since a measurement result / TCH block
is expected every two bursts anyway the problem can only be noticed when
a FACCH transmission is going on and the frame numbers of the BFI TCH
blocks appear to be missaligned towards the FACCH block.
The reason is that the incoming bursts are shifted into a 6 burst wide
buffer. The decoding functions always look at the beginning of that
buffer while the bursts are shifted into the buffer from the end. A
facch will always fit exactly in that buffer but TCH/H blocks are only
4 bursts wide and thereofre they need two additional bursts until they
reach the coverage of the decoding function. Lets fix this by putting
the correct frame number (from two bursts before) into the remap
functions in order to get the correct beginning of the block.
Since the FACCH transmission uses six blocks it takes out two TCH
blocks. This means that if we count the FACCH block we end up with a gap
of one TCH voice block. Lets generate a dummy measurement to compensate
the gap. This will also match the behavior of the osmo-bts-sysmo phy.
Change-Id: I1ad9fa3815feb2b4da608ab7df716a87ba1f2f91
Related: OS#4799
in function rx_tchh_fn() the variable meas_avg is not initalized. This
is not always a problem, since most of the time trx_sched_meas_avg() is
populating the variable properly. In cases where a FACCH is transmitted
(chan_state->ul_ongoing_facch = true) the variable is left unpopulated.
In order to have at least stable values for those cases, initalize the
variable with zeros for the ongoing facch phase.
Change-Id: I5c3c1c41d22f9edaaf6bd4478dd04f090dca12a9
Fixes: CID#214480
Make sure that we pick the correct UL measurements from the
history when we deal with AMR SID frames (SUB frames).
Change-Id: I902bb47d68742d2589156f61099b67a0edbaf40b
Related: OS#2978
Currently the UL measurements (RSSI, ToA256, C/I) of the burst that
concludes a block are passed up to the higher layers. This means
that the measurement values of the other bursts are skipped.
Let's keep record of all UL measurements and average the values
before we pass them up to the higher layers. Use a simple ring
buffer to store the measurement history (up to 8 unique entries
for now). Remove *_num/*_sum variables from l1sched_chan_state.
Change-Id: I2b02b51fea5664f161382a4ddc63dbf14ffc9ac5
Related: OS#3032, OS#2978
This change simplifies access to generic logical channel state
(struct gsm_lchan) from osmo-bts-trx specific state (struct
l1sched_chan_state), so there is no need to look it up using
get_lchan_by_chan_nr() on receipt of each Uplink burst.
Change-Id: Ic4378020f980845b962f71b9e4b7faea738bc174
This change is similar to what we did for Uplink bursts:
- group all Downlink burst parameters into a single structure,
- allocate it once and pass a pointer to lchan handlers,
- pass a pointer to trx_if_send_burst().
Given that the structure is allocated and (zero-)initialized in
trx_sched_fn(), we can get rid of some memset() calls in lchan
handlers and thus improve the overall performance a bit.
Change-Id: If3014e69746559963569b77561dbf7b163c68ffa
It's easier to maintain the logical channel handlers in separate
files, rather than in a huge one (scheduler_trx.c, ~2k lines).
Change-Id: Ie5663fd90596b4800a4546675a323250bbb24c80
Vadim Yanitskiy
Pau Espin
Philipp Maier