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.

handling of PDCCH order. stoping UE-specific scheduler during RA procedure. checking for DCI format (resource allocation) to not overwrite resource_block_coding for format 1A DCIs.

removal of LOG_I put for debugging.

not finished, UE may not work, many things bad/to fix properly

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.

addition of MPDCCH format 5. X_u_br sequences for BL/CE UE support and bugfixes in rx_prach0 for eMTC.

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

Note: this commit is work in progress. Contains initial integration of NFAPI data structures which are tested for TX path. RX path to follow.

Optimisation of rx_pdcch : save some time by reading one symbol pdcch first and read symbol 2 and 3 if needed
Optimisation of nb of candidate when searching DCI

We have to not only ensure that the CCE is free but
also that it's below the number of availables CCEs
with respect to the current PDCCH size.

we can compute CCE_max_used_index out of the loop.

get_nCCE returns the number of available CCEs.

We can put the CCEs numbers [ 0 .. get_nCCE-1 ],
so we need to use <, not <=.

--ue-trace : Enabling UE trace for debug
--ue-timing : Enabling UE timing trace
--ue-no-log : Disabling all LOG_X traces