The struct member gen_idle_blocks controls whether the the PCU has to
generate dummy blocks to fill idle periods or if this task is left to
the BTS hardware.
Since idle dummy blocks only have to be transmitted on the C0 carrier,
we should rename the gen_idle_blocks struct member to
gen_idle_blocks_C0.
Related: OS#6198
Change-Id: If9511ed911f9c5d6d463881a387a9e7d11a15465
When a PDCH is idle, then the gaps are filled with dummy blocks. OsmoPCU
supports generating the dummy blocks locally, so that a continous stream of
PDCH blocks is sent to L1. However, some BTS models (the OsmoTRX based models
in particular) are able to generate the idle blocks locally. In this case the
PCU should leave the genration of the dummy blocks to the BTS in order to
save processing time and load on the PCUIF interface.
In gprs_rlcmac_sched we already have a flag to skip idle frames in case we do
not use the so called "direct phy access". A similar mechanism also exists in
pcu_l1_if.cpp in function pcu_rx_rts_req_ptcch().
Unfortunately this check is not implemented correctly. The flag gets set when
the ENABLE_DIRECT_PHY define constant is set. However, this does not say
anything about whether the BTS model supports the generation of idle blocks or
not. The define constant is intended to be used to disable direct phy related
code in on platforms where no direct phy code is used or cannot be used. We
must instead check the BTS model (bts->bts_model) in order to decide whether
this particular BTS type requires the generation of dummy blocks or not.
Related: OS#6191
Change-Id: I7a08d8cc670fa14f7206ffffdbc22351f3668a17
This allows having full TS information, not only ts_no, which will be
needed later on followup patches.
Change-Id: I1efccb32c5afa4fe62233bf114ea95b6fbbe1a06
The pdch pointer contains more info than just timeslot number. For
instance, it contains information about the TRX owning the TS.
Change-Id: Ic31a7360a29e61f70bb1338ddab6f5f31aa8b26e
This will allow also validate easily the TRX is the correct one too, not
only the TS number in any random TRX.
Change-Id: Ib1a62b6e7b465253ee7cba63bf5e277f8aa8eaea
The state_fsm field will be moved to subclass (DL_TBF/UL_TBF) in a
follow up commit when splitting the tbf_fsm.c implementation per
subclass.
Rearrange a bit the code to access the using the subclass pointer in the
only sublcass where it needs to be used (DL_TBF).
Change-Id: I360485c73be8636565f89ba29796d84ac94fd94e
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: I4a49dbeeec89b22624c968152118aecf8886dac6
This way PCU always answers DATA.ind and the BTS can still clearly
identify idle frames. It also simplifies testing and verification of
correct behavior.
Related: SYS#4919
Change-Id: Ife718eeed2af011479c03099ea109518f04567bc
We also want to avoid sending idle blocs in TRX0 to the BTS, so that the
BTS can be aware of blocks being idle and then submitting dummy blokcs
by itself applying required BCCH Carrier power reduction.
Related: SYS#4919
Change-Id: Idd58d2a09c3947098b960cfcb5cd1b7b7bca3d84
These messages are expected under some circumstances, such as when
direct phy is used and a chan is disabled (eg. dyn TS). This happens
because PCU asks for chan de-activation through PCUIF while at the same
time marking the PDCH locally as disabled. Hence, in the time the BTS
manages to disable it on the lower layers, the phy still sends us
RTS indications.
Let's keep it under NOTICE to avoid clogging the logs in production
setups which are usually using global level of NOTICE or ERROR.
Related: OS#5222
Change-Id: Iab9e1590b504bf05dc693e27550b30db0dffcbc7
Method is renamed since it clearly relates to getting DL ACK/NACK, no
CTRL ACK.
use same methods in both scheduler and internal use since they are
expectd to be run in the same code path by the scheduler. This way we
make sure the same conditions apply and it's clearer when looking at
the code.
Change-Id: Ib0e9b9547f5292b95064bab2dc182fdf659f0518
Go through all callers of as_dl_tbf() and as_ul_tbf(), and make sure
they can handle the possible NULL return value.
OS#5205 reports a NULL deref crash of osmo-pcu at pdch.cpp:525. The
immediate cause is that as_dl_tbf() may well return NULL, which this
caller does not handle and instead dereferences immediately.
This is a code path that apparently assumes that a DL-TBF should always
be present. The higher level cause for the NULL DL-TBF has not been
identified.
Related: OS#5205 SYS#5561
Change-Id: I8ce21be6836549b47a606c00b793d6f005964c5c
msg->data_len is the total number of bytes available in the buffer,
while for CTR_RLC_DL_BYTES we need to count size of the actual
payload within the buffer. A consequence of this bug: osmo-pcu
was counting more Downlink bytes than it's actually transmitted.
Change-Id: I6884d220f3d06a79b16c18ccc2d2a6cd047b8251
This is only an initial implementation, where all state changes are
still done outside the FSM itself.
The idea is to do the move in several commits so that they can be
digested better in logical steps and avoid major break up.
Related: OS#2709
Change-Id: I6bb4baea2dee191ba5bbcbec2ea9dcf681aa1237
The code path running into first call of "create_packet_access_reject()"
is a superset condition of the second one, so the second one will never
be hit.
As a result first, this block:
"""
else if (tbf == tbfs->ul_ass && tbf->direction == GPRS_RLCMAC_DL_TBF)
if (tbf->ul_ass_state_is(GPRS_RLCMAC_UL_ASS_SEND_ASS_REJ))
msg = tbfs->ul_ass->create_packet_access_reject();
else
msg = tbfs->ul_ass->create_ul_ass(fn, ts);
"""
Can be simplified into:
"""
else if (tbf == tbfs->ul_ass && tbf->direction == GPRS_RLCMAC_DL_TBF &&
!tbf->ul_ass_state_is(GPRS_RLCMAC_UL_ASS_SEND_ASS_REJ))
msg = tbfs->ul_ass->create_ul_ass(fn, ts);
"""
Next, one can see that previous condition still forces
!tbf->ul_ass_state_is(GPRS_RLCMAC_UL_ASS_SEND_ASS_REJ) to be always true
if we ever reach that code, so it can be dropped.
Change-Id: I62e2255e28fc4f43fe0a31259ebf18ad00e7e357
This way PCU can now detect whether scheduled UL blocks through USF
were never received. This allows in a follow-up patch to start
increasing N3101 properly.
Related: OS#5033
Change-Id: Ia99c9edad6e5bd837e9baeb4fb2683b227887957
When the scheduler detects it's time to receive a UL block due to a
scheduled poll, if that polling is done on a UL TBF, then use its USF if
available instead of using USF_UNUSED (=7) when sending a DL block on
that same FN.
This is not really needed for correct work, since MS take care
themselves of scheduling a UL block when they receive the poll (RRBP)
some time before, and don't check the USF at the time of transmitting.
In any case, it helps understand better when looking at pcap traces that
indeed it a UL block from that MS was requested, instead of setting USF
to 7.
Related: OS#5033
Change-Id: I2ad9d8ea6afc8f83192033470bd27010a7474430
Simply use the UL TBF pointer all along until the end, instead of setting
both the UL TBF pointer plus the usf var.
This commit is also a preparation for next commit which also selects UL
TBF when a poll is available, to set its USF in the DL message instead
of "USF_UNUSED".
Change-Id: I3aa3886932ef87db18ed7ff6991ea315f481990b
With previous code, a skipped TBF could be returned despite not matching
the conditions, since at the end of the loop the tbf pointer was
returned.
Related: OS#5020
Change-Id: If6dccec86c7a655bf1c62f333cfbc8d2c507c94f
Take the time to also do small refactorings to clarify and simplify the
function, by using rts_next_fn() already available in pcu_utils.h and
getting rid of poll_tbf from tbf_candidates, which clearly follows
another objective.
Using PDCH UL Controller has the advantage that we don't need to check
poll_scheduled() on each TBF, but only do the query once.
Related: OS#5020
Change-Id: Ia60bb5249a9837dec1f42180e44d9848334d86d6
Right now we handle different types of UL allocations in different
classes like PollAllocator and SBAllocator, and they usually don't take
into account the other one in most cases. Furthermore, those objects are
usually per-BTS object, instead of per PDCH object.
This is a first step towards having a unified per-PDCH controller which
takes care of controlling what is scheduled and hence expected on the
uplink. Each PDCH has a UL Controller which keeps track of all reserved
uplink frame, be it SB, RRBP poll or USF assigned, all under the same
API.
As a first step, only the SBA part is fully implemented and used (being
it the easiest part to replace); TBF poll+usf will come in follow-up
patches later on. As a result, the SBAllocator per-BTS class dissappears
but some of its code is refactored/reused to provide more features to the
gprs_rlcmac_sba object, which is also further integrated into the new UL
Controller.
Related: OS#5020
Change-Id: I84b24beea4a1aa2c1528f41435f77bd16df2b947
The DL NACC related message (PKT Cell Neighbor Data/Change Continue)
are filled with the TFI of the target TBF. Hence, only select the tbf
for NACC transmission if the related TBF already has a TFI assigned.
Otherwise, "OSMO_ASSERT(tbf_is_tfi_assigned(tbf));" in nacc_fsm.c when
generating messages may be hit.
Related: SYS#4909
Change-Id: I72b2dff28aacdb04909c098c94834ff79f55b31d
Use the fact that the MS must answer the RRBP of the Pkt Cell Change
Continue with a CTRL ACK to find out whether the message was received
successfuly or a retransmission is potentially required.
3GPP TS 44.060:
"""
When the mobile station receives the PACKET CELL CHANGE ORDER or
the PACKET CELL CHANGE CONTINUE message the mobile station shall
transmit a PACKET CONTROL ACKNOWLEDGMENT message in the specified
uplink radio block if a valid RRBP field is received as part of the
message; the mobile station may then switch to a new cell.
"""
Related: SYS#4909
Change-Id: I7cc28922e71699598da0ef6eb90136a47d3c002f
A new nacc_fsm is introduced per MS object, with its partner priv
structure struct nacc_fsm_ctx, which exists and is available in the MS
object only during the duration of the NACC procedure.
The NACC context is created on an MS whenever a Pkt Cell Change
Notification is received on Uplink RLCMAC, which asks for neighbor
information of a given ARFCN+BSIC.
First, the target ARFCN+BSIC needs to be translated into a CGI-PS
(RAC+CI) address. That's done by asking the BSC through the Neighbour
Resolution Service available in osmo-bsc using the CTRL interface.
Once the CGI-PS of the target cell is known, PCU starts a RIM RAN-INFO
request against the SGSN (which will route the request as needed), and
wait for a response containing the SI bits from the target cell.
After the SI are received, the scheduler is instructed to eventually
poll a TBF for the MS originating the CCN, so that we can send the SI
encapsulated into multiple Packet Neighbor Cell Data messages on the
downlink.
One all the SI bits are sent, the scheduler is instructed to send a
Packet Cell Change Continue message.
Once the message above has been sent, the FSM autodestroys itself.
Caches are also introduced in this patch which allows for re-using
recently known translations ARFCN+BSIC -> CGI-PS and CGI-PS -> SI_INFO
respectively.
Change-Id: Id35f40d05f3e081f32fddbf1fa34cb338db452ca
Sine we don't yet implement properly all resegmentation of blocks from
same MCS family type, when requiring a GMSK DL block (due to GPRS+EGPRS
multiplexing limitations) we need to skip retransmitions, otherwise we'd
be incorrectly picking a DL block which was already built with a
potentially higher MCS value.
The "DL_PRIO_NEW_DATA" prio serves two purposes:
* There's new data to send
* There's some nacked data to be retransmitted
The 2nd purpose has, later on, more priority over the 1st one when the tbf
is selected (see gprs_rlcmac_dl_tbf::take_next_bsn()).
Until now we were handling correctly the case where the tbf was skipped
in case the prio was to resend unacked data (DL_PRIO_SENT_DATA), but
was incorrectly selected when it'd send nacked data. Let's fix it by
specifically checking w->resend_needed() < 0.
Change-Id: I253de8e1a190a9adb56160f38892c9e43e2c0272
It could happen as of current implementation that a TBF was created as
GPRS due to the MS being non-egprs, and later on the MS was upgraded to
EGPRS due to newly received information from the MS.
Hence, in order to infer if the data block is EGPRS or GPRS, let's
better check for the TBF info, which is the one really mandating the
kind of dl block to generate.
Change-Id: I49720fb3a69ca972cd1973de937ac8ee77615431
This patch doesn't really tests whether osmo-pcu can work on a multi-bts
environment, but it prepares the data structures to be able to do so at
any later point in time.
Change-Id: I6b10913f46c19d438c4e250a436a7446694b725a
Philipp Maier
Pau Espin
Vadim Yanitskiy
Oliver Smith
Neels Hofmeyr