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: I73be012c01c0108fb6951dbff91d50eb19b40c51
Regarding the removal of burst_mask2str() from the TCH/H handler,
it does not make sense to print it because the mask is already
shifted and an earlier logging should already contain this info.
Change-Id: I42d20e2da73c21ca366dd246244cd716c8ccb459
Related: OS#4823
Similar to what we do in osmo-bts-trx, group everything related to
an Uplink burst into a structure. Pass a pointer to this structure
to the logical channel handlers. This makes the code easier to read,
and facilitates sending NOPE indications to the transceiver
(will be introduced in the upcoming patch).
Get rid of sched_trx_handle_tx_burst(), and instead just call
sched_trx_a5_burst_enc() directly from sched_frame_clck_cb().
Change-Id: Id45b27180c233fdc42ae1ef0b195554dd299a056
Related: SYS#5313, OS#1569
It may happen that the burst reception would start from bid != 0:
<0005> sched_trx.c:263 (Re)configure TDMA timeslot #2 as TCH/H+SACCH
<0005> sched_trx.c:420 Activating lchan=TCH/H(0) on ts=2
<0005> sched_trx.c:420 Activating lchan=SACCH/TH(0) on ts=2
<0006> sched_lchan_xcch.c:96 Received incomplete data frame at fn=0 (0/104) for SACCH/TH(0)
<0006> sched_lchan_xcch.c:106 Received bad data frame at fn=0 (0/104) for SACCH/TH(0)
so in that case, both measurement processing and the frame number
calculation would yield incorrect and/or incomplete results. The
Rx burst mask can be used to eliminate this problem.
In particular, if we shift it left instead of cleaning, it would
never be equal 0x00 after at least one burst is received. This
would allow us to skip decoding of an incomplete frame at the
beginning when the logical channel was just activated.
Note that TCH/H handler is not affected because it already uses
the strategy described above, so we keep it unchanged.
Change-Id: Ib8ddf2edd5ef84f2ab12155f7a8874c9fc56d436
Related: OS#3554
Using TDMA frame number of a burst with bid=0 is fine for xCCH,
but not for TCH and FACCH, because they use the block-diagonel
interleaving. A single block on TCH may be interleaved over
8, 4 or even 6 consecutive bursts depending on its type.
Since we now have the measurement history, we can attach TDMA
frame number to each measurement set, and then look up N-th
one when averaging the measurements in sched_trx_meas_avg().
Change-Id: I9221957297a6154edc1767a0e3753f5ee383173f
These BFI (Bad Frame Indications) substitute speech frames stolen
by FACCH/F or FACCH/H frames, so there can be no bit errors in
something that was not even transmitted over the air interface.
Change-Id: Icdb6209f75ead6581e3c18aeee0da9831aaa272a
According to 3GPP TS 45.003, clauses 4.2.5 and 4.3.5:
- one FACCH/F frame steals a single speech frame,
- one FACCH/H frame steals two speech frames.
A BFI (Bad Frame Indication) needs to be sent for each stolen
speech frame. This does not apply to CSD (data) channels though.
The BFI frames must have measurement data attached to them, and
due to their virtual nature (they do not actually come from the
air interface), the measurements must be crafted by trxcon.
Assigning a negative value to n_errors makes the code below the
'bfi' label craft fake measurement data. Otherwise, the actual
measurements belonging to the FACCH frame will be used.
Change-Id: Ia2f7c3cf7b1ef3737da6b1818cae2f001ee8768f
So far we used to store the sums of ToA and RSSI measurements in the
logical channel state, and after decoding of a block, we did calculate
the average. This approach works fine for xCCH and PDTCH, but when it
comes to block-diagonal interleaving (which is used on TCH/F and TCH/H
channels), the results are incorrect. The problem is that a burst on
TCH may carry 57 bits of one encoded frame and 57 bits of another.
Instead of calculating the sum of measurements on the fly, let's push
them into a circular buffer (the measurement history), and keep them
there even after decoding of a block. This would allow us to calculate
the average of N last measurements depending on the interleaving type.
A single circular buffer can hold up to 8 unique measurements, so the
recent measurements would basically override the oldest ones.
Change-Id: I211ee3314f0a284112a4deddc0e93028f4a27cef
Instead of counting both RSSI and ToA measurements separately,
let's have a single counter in trx_lchan_state.meas struct.
Change-Id: I45454a3ac92b8cc85dd74092e4ab6eb350f20c9a
GSM48_CMODE_SIGN means 'signaling only', so we shall not send
bad frame indications in this state. Instead, it makes sense
to send dummy L2 frames like we do for xCCH channels.
Change-Id: Ie39d53522cafab265099076b3194fa96aff217ba
This field of the logical channel state structure was not used at
all as there is nothing related to A-bis / RSL in trxcon itself.
Change-Id: Iec1abf777a74cf57deadafa95e2337cba5d02842
Instead of passing the information about a logical channel, it
makes sense to pass the pointer to its state where everything
is stored. This approach would allow to avoid adding more
arguments every time, e.g. in case of AMR.
Change-Id: I91fe86fef43aac68776a58c9acc37ef2a9ee8042
We used to trust (and still doing this) the messages coming from
L1CTL interface too much, and not to check the primitive length
before passing the payload to the libosmocoding API. As was
discovered and described in OS#3415, sending a L1CTL message
(either DATA_REQ, or TRAFFIC_REQ) with an incorrect length
(lower than expected) may cause heap overflow.
Let's explicitly check a primitive before encoding, and drop it
if its length doesn't match the expected value(s).
Change-Id: I258ee9f6d0124b183b1db23a73f1e523fcea89a8
Fixes: OS#3415
We shall always send traffic frame indications, even if received
frame is incomplete or decoding was failed. This is required
for proper Measurement Reporting.
Change-Id: I99e134699796c7075299459e96b2f2d462636619
Since this change, each lchan handler shall manually indicate
a type of both message indications and confirmations.
Change-Id: I02e0b87d61c127d2f6f5b9532909af78332bf707
There's no need to express ToA value as a float. Let's turn it into
an int16_t with 1/256 symbol period accuracy throughout the code to
avoid both float arithmetic as well as loosing any precision.
Inspired by Idce4178e0b1f7e940ebc22b3e2f340fcd544d4ec.
Change-Id: I99c0f38db08a530d5846c474aba352aa0b68fe86
Having a possibility to preprocess UL burst before sending to
transceiver is required for the further ciphering support
integration and probably some other tasks.
Change-Id: Ia6eead5d4f51d7c0bf277b9d5ebb0a74676df567
Previously, each lchan handler used to obtain and delete primitives
from a timeslot's tranmit queue itself. This approach entails many
potential problems and bugs:
- The lchan handlers shall not do that by definition, they
should encode and decode frames according to GSM 05.03.
- In some cases (e.g. TCH), a single transmit queue may contain
primitives of different types (e.g. TCH, FACCH and SACCH). At
the same time, the lchan handlers don't care and don't even
know about each other. So, this could cause an unexpected
behaviour in some cases.
This change separates all primitive management routines,
providing a new API for obtaining and dropping them.
"Write programs that do one thing and do it well."
Change-Id: I29503ece51903784bc53541015285234471c8d15
It's good to write, keep and make the source code as much modular
as possible. So, Tte primitive management code was separated to
the 'sched_prim.c' and going to be extended in the near future.
Change-Id: Ifec8c9e4f2c95c72b00772688bcb5dc9c11d6de7
Previously, we used to drop a frame if decoding wasn't successful.
This way, the higher layers didn't even know about that, so the
local counters and Measurement Reports were incomplete.
This change makes scheduler to forward L2 frames in any case,
setting the num_biterr for each of them. In case of decoding
error, a dummy (payload filled by 0x00) L2 frame will be sent.
Change-Id: I31011d8f3ca8b9a12474cd0bc653faed18391033
This change implements basic TCH/F lchan handlers for both data
reception and transmission. Only FACCH (signaling), FR and EFR
payloads are supported at the moment.
Change-Id: If6b0eaede2b484484d2a824e7219ff04483266a1
Oliver Smith
Vadim Yanitskiy
Vadim Yanitskiy