1. Previous SW configuration for different RRC version relies on whether macro Rel10,
Rel14 defined or not by checking #ifdef Rel14 or #if defined(Rel10) || defined(R14).
Whenever there is a newer RRC version, e.g. Rel15, it will be very a tedious and
error-prone job to add defined(Rel15) in every place.
2. Some RRC messages are defined in release 13 instead of release 14, NB-IoT
feature is one of such example. Our code shall reflect this fact instead of using
an afterward version number in software configuration.
3. Some RRC messages or some fields of certain RRC messages are added in the middle
a release, e.g. SystemInformationBlockType1_v1310_IEs_t defined in RRC 13.1.0
and RRC 9.2.0 made some changes to SIB12 and SIB13 so we have sib12_v920 and
sib13_v920 fields in SIB12 and SIB13's struct.
We need a finer grain of control when using ASN1 from different RRC version.
4. S1AP also has this problem that it use UPDATE_RELEASE_9 and UPDATE_RELEASE_10 to
differentiate between various S1AP version.
This commit propose using MAKE_VERSION(x,y,z) to designate the version number and
modify current conditional compilation accordingly.
Note: 2018/04/16, Modified based on Cedric's comment.
The code was very unclear and potentially buggy.
This new version is more robust.
We can waste up to 2 bytes because the last header in the MAC PDU
does not contain a length field and when we request data from RLC
we suppose a 3-bytes MAC header. This might be optimized at some
point, but the benefit would be low.
This commit also contains some general cleanup:
- formatting
- variables' types: let's use 'int' instead of trying to be clever
by using small types that may generate bugs if the value is
too big
- remove 'tpc_accumulated' which was globally used for all UEs
and has no purpose other than logging. We may want to rework
a bit the TPC machinery at some point. As the code is today
we may repeatedly send TPC over and over without caring about
the 3GPP limits, in which case no one knows how the UE is
supposed to behave: does it clamp the current max value or does
it accumulate over and over and take the clamped value to compute
its actual power? If we send a reverse TPC (reduce power instead
of increase) does it do it immediately or does it have to decrease
n+1 times if we previously ordered it to increase n times?)
We do not address the problem of prioritizing LCIDs. As of today there
is only one dedicated traffic channel (DTCH), so it's not a problem
at this point.
What has been tested:
- monolithic eNB 5/10/20MHz with one cots UE, TCP/UDP UL/DL. At 20MHz the
machine used was not capable of keeping up, generating lots of Us
and Ls when the throughput reaches 60Mb/s. USRP B210 was used.
This commit fixes issues introduced by the previous commit.
Summary of work:
- cleanup:
- fix LOG_XX to be less verbose
- fix cmake_targets/CMakeLists.txt
- fix oaienv
- remove dead code
- bug fixes:
- in openair1/SCHED/fapi_l1.c we had:
eNB->pdcch_vars[subframe&1].num_dci = number_dci;
should be:
eNB->pdcch_vars[subframe&1].num_dci = 0;
This bug let the PHY send more DCIs than what should have been
sent because num_dci is incremented later on in the code.
This fix may be a problem for fapi mode, to be checked.
- add new T VCD traces
- revert openair1/PHY/TOOLS/file_output.c to 'develop' version
- remove thread_id in logRecord/logRecord_mt
- revert (and adapt) configuration files
- be careful when doing frame++, we need to % 1024
- revert target_rx_power in openair2/LAYER2/MAC/eNB_scheduler_ulsch.c
- NFAPI:
- the open-nFAPI code has been included in the repository. See nfapi/README.
Maybe we should "git clone" the Cisco repository instead. We have to be
careful of availability though.
What has been tested:
- monolithic eNB FDD 5/10MHz with one UE, iperf UDP/TCP uplink/downlink
Anything else may fail to work, especially the FAPI mode, which has not
been tested at all.
It has been chosen to not include the full history of commits
from David. He included a binary version of wireshark, probably
a modified one that understands NFAPI. Wireshark is released under
the GPL license, we cannot include it in the repository. We could
have done a next commit to remove this binary. But then it would
still be present in the history of commits, which may not be allowed.
And it would take space on disk. We could edit the history to remove
wireshark entirely. But this operation is too complicated.
There was also a pcap capture file, which has nothing to do in
the history of commits and would take space on disk. There again,
it's too difficult to edit the history to remove it.
There was a file .gitignore that was also removed.
The original history can be found on David's repository:
https://gitlab.eurecom.fr/daveprice/openairinterface5g/
The branch is: nfapi-ru-rau-split.
A copy of that branch has been included in the internal OAI
repository, for those who have access to it.
The branch is the same. The last commit ID is
9106438239e0bc626ff1fa1d97d911caadd0fbb9.
You can compare the current commit with the commit 9106...
to see what differs.
The current commit has to be considered non-working.
The commit following the current commit will fix problems with
the work in the current commit.
If you use git bisect, don't spend time analyzing the current
commit.
Includes the following updates:
1. oaisim/lte-softmodem in noS1
2. UE fixes for oaisim
3. IF4p5 fixes (doesn't work on develop)
4. UE fixes for DCI handling (corrects problem introduced in develop)
Conflicts:
cmake_targets/CMakeLists.txt
targets/SIMU/USER/oaisim_functions.c
- change target values
- change upper/lower limit to trigger a tpc
- don't use ul_cqi from SR
The value of ul_cqi is not convincing, for both PUSCH and PUCCH,
more work/analysis is required.
- re-use ta_timer
- when ta_timer is running:
- no TA sent to UE
- no TA from UE (for UE to have time to apply previous TA command)
- decrease ta_timer every TTI
- be careful to use correct value of ta_update (31 means no TA)
Maybe not correct, to be checked.
- don't use o_flip anymore in ulsch_decoding
- remove dl_cqi from eNB_UE_STATS
- put dl_cqi[NFAPI_CC_MAX] in UE_sched_ctrl
- adapt code for this dl_cqi change (from eNB_UE_STATS to UE_sched_ctrl)
- extract_pusch_csi has been fixed for CQI_ReportModeAperiodic_rm30,
the others need to be done. Program will exit if one uses them.
Not sure if setting sched_ctl->dl_cqi[CC_idP] has to be done in this
function...
This commits contains several fixes to improve a multi-UE scenario.
This is not the end of the story.
Summary of work:
================
1 - improve SR (scheduling requests):
We configured n1pucch == 3 for scheduling requests, for all
UEs. We now use 71 - UE_id/10.
For it to work, it is vital that pucch_nRB_CQI in the configuration
file is set to 0, otherwise the SR will go to an RB used for
PUSCH and uplink decoding will fail whenever an UE does SR.
Note that we will have problems with 20MHz when we use a CCE that
let the UE send the ACK/NACK using a n1pucch allocated for SR,
because when the PDCCH is of size 3, we can have 87 CCEs
and it may lead to an n1pucch colliding with one for SR.
The work done in this patch is a quick solution, seems to work
with 10MHz.
The real solution is to disable the use of those CCEs that would
lead an UE to use a n1pucch colliding with an SR n1pucch. Then
we can use whatever n1pucch we want for SR, as long as the
scheduler protects them.
Impacted files: configuration files
openair2/RRC/LITE/MESSAGES/asn1_msg.c
2 - some fixes for uplink scheduling:
- Do not use PRACH for PUSCH, that leads to too many false
PRACH detection. Plus the PUSCH receiving may fail if one
UE uses the PRACH at the same time.
- Take care of retransmissions. That was not done at all, so
we could allocate one RB to several UEs. The current design
of the code makes it hard to do it properly, so we chose a
quick and dirty solution, which is to increase "first_rb"
to skip any RB used for retransmission. In this process we
may skip a lot of free RBs. A proper solution is needed here.
- Do not allocate the last RB. This one is used for PUCCH.
It was sometimes allocated to PUSCH.
- In the pre-processor we didn't pre-allocate RBs to UEs
with an empty buffer status. We didn't check if the UE
sent an SR. For example in a three UEs scenario, we
could have the third UE never scheduled in the uplink.
- rb_table_index was not decreased properly, so we allocated
too much RBs to some UEs and thus not enough to others.
Impacted files: openair2/LAYER2/MAC/eNB_scheduler_ulsch.c
openair2/LAYER2/MAC/pre_processor.c
openair1/SCHED/phy_procedures_lte_eNb.c
3 - some fixes for downlink scheduling:
- The check on CCE allocation was not correct. We did something
like:
if (cce allocation is possible) {
prepare
}
We should have done:
save current cce allocation
if (cce allocation is possible) {
allocate cce
prepare
}
reset current cce allocation
Basically, when we scheduled several UEs, they were checked
separately, and the totality of them was not checked.
Impacted file: openair2/LAYER2/MAC/eNB_scheduler_dlsch.c
- The retransmissions are probably not handled correctly.
Check in openair2/LAYER2/MAC/pre_processor.c, near
the comment "// control channel or retransmission",
the case "round > 0" was added. It's probably not enough,
even maybe not correct.
- Change SF05_LIMIT with SF0_LIMIT. We accept to use
central blocks in SF 5. The code was also not correct,
vrb_map was not set properly because the loop on j
was wrong for the last RBG (which can have one less
RB than the others).
This is not satisfying. The real solution is to use the
central RBs and check that the MCS used is compatible
with the numbers of resource elements allocated (we don't
want to put too more data bits than what fits).
4 - some fixes in PUCCH decoding:
See: openair1/PHY/LTE_TRANSPORT/pucch.c
Probably not enough. Some more work and analysis is
required for a proper use of the PUCCH. What we see
is that the PUCCH constellation gets wrong when there
are several UEs, meaning the received ACK/NACK is
not properly decoded (this, or something else...).
5 - several fixes/checks added here and there:
- The final allocate_CCEs in eNB_dlsch_ulsch_scheduler
is checked and we brutally exit if it fails.
- We exit in get_num_pdcch_symbols in case of failure
(this should never happen anyway, no big deal normally).
- Some logs added or changed to error/warning instead
of debug.
- In dlsch_scheduler_pre_processor an abort() was added.
The code here looks suspicious.
- In assign_max_mcs_min_rb, rb_table_index was not set
to 2, the value 0 was used. This was not correct.
What remains to be done:
========================
- Correct CCE allocation (take into account SR n1pucch,
check that all the n1pucch that will be used are "compatible").
- Take into account the PHICH when scheduling uplink. As of
today it is very possible to have two UEs use the same PHICH
group and PHICH sequence index. We can use n_DMRS in the DCI
to have uniqueness (see 36.213 table 9.1.2-2). We can drop an
allocation if there is no free PHICH group/sequence index for
a given UE.
- When there is an uplink retransmission in the PRACH, we have
to disable PRACH detection. It is possible that one UE does
PRACH at the same time, but then what to do? We could use
DCI0-based retransmission in this specific case maybe...
- Handle free RBs in uplink in a much better way in case of
a retransmission. We may have a lot of free unused RBs with
the current code.
- Check downlink retransmissions. Not much has been done there.
- Surely more stuff not clear yet. In some situations we don't
have a good behavior of the system. Hard to describe more
precisely at this point.
This bug happens when we detect uplink failure for one UE.
In this case, a DCI format 1A is sent to the UE to ask it
to do random acces.
The way this DCI is generated was not compatible with how
the software is organized. It was expected that the DCI are
added (with add_ue_spec_dci and add_common_dci) in a very
specific order: first all DCIs in common space are added
(with add_common_dci) then all DCIs in UE specific space
are added (with add_ue_spec_dci).
The problem was that the DCI format 1A DCI sent to the UE
for it to do random access is added (with add_ue_spec_dci)
before the DCIs in common space.
That totally messed up the logic in add_common_dci and
add_ue_spec_dci.
The solution is to get rid of Num_common_dci and Num_ue_spec_dci,
replace those two counters by only one (Num_dci) and add
"search_space" in the dci_alloc structure to be used later by
the function "allocate_CCEs" when calling "get_nCCE_offset".
The software had to be adapted to the new variables, everywhere.
I am not sure that the simulators work. It seems that some
of them didn't use Num_common_dci and Num_ue_spec_dci to
decide on what space (common or UE specific) to put the DCI,
but relied on the rnti (comparing with SI_RNTI). To be tested
properly.
The modified simulators are:
- openair1/SIMULATION/LTE_PHY/dlsim.c
- openair1/SIMULATION/LTE_PHY/dlsim_tm4.c
- openair1/SIMULATION/LTE_PHY/dlsim_tm7.c
- openair1/SIMULATION/LTE_PHY/framegen.c
- openair1/SIMULATION/LTE_PHY/pdcchsim.c
- openair1/SIMULATION/LTE_PHY/syncsim.c
Bi-Ruei, Chiu