1. 25 Sep, 2017 2 commits
  2. 24 Sep, 2017 2 commits
  3. 22 Sep, 2017 2 commits
  4. 21 Sep, 2017 4 commits
  5. 19 Sep, 2017 1 commit
  6. 15 Sep, 2017 1 commit
  7. 14 Sep, 2017 1 commit
  8. 29 Aug, 2017 1 commit
  9. 24 Aug, 2017 1 commit
    • Cedric Roux's avatar
      improve multi-UEs scenario · 622b919b
      Cedric Roux authored
      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.
      622b919b
  10. 23 Aug, 2017 1 commit
    • Cedric Roux's avatar
      mobipass standalone driver · c866677a
      Cedric Roux authored
      How to use:
      
      1 - compilation of softmodem:
        ./build_oai --eNB -t ETHERNET
      
      2 - compilation of mobipass driver:
        cd cmake_targets/lte_build_oai/build
        make oai_mobipass
        ln -sf liboai_mobipass.so liboai_transpro.so
      
      3 - configuration:
        edit the configuration file, set "node_timing" to
        "synch_to_mobipass_standalone"
        that is, have the line:
          node_timing               = "synch_to_mobipass_standalone";
      
      4 - run:
        run as usual: sudo ./lte-softmodem -C <configuration file>
      c866677a
  11. 17 Aug, 2017 3 commits
  12. 14 Aug, 2017 1 commit
  13. 13 Aug, 2017 1 commit
  14. 11 Aug, 2017 1 commit
  15. 10 Aug, 2017 1 commit
  16. 08 Aug, 2017 1 commit
    • knopp's avatar
      L1/L2 scheduling extensions for BL/CE operation, BR random-access procedure,... · ad98f5aa
      knopp authored
      L1/L2 scheduling extensions for BL/CE operation, BR random-access procedure, BR PRACH detection. Still untested, but compilation succeeds. Missing elements in L2 - PUSCH programming for Msg3, Msg4 retransmission programming for BL/CE. DLSCH/ULSCH programming for UE-specific DLSCH/ULSCH for BL/CE
      ad98f5aa
  17. 03 Aug, 2017 1 commit
    • Cedric Roux's avatar
      bugfix for phy simulators (not sure if enough) · 9e4f700a
      Cedric Roux authored
      With the new threading architecture of the UE dlsim
      (and others) does not work properly anymore.
      
      When looking at the scope, you see a difference
      in PDSCH LLR display. The end is always 0 where
      in the current develop branch (tag 2017.w25) it's not.
      
      This commit attempts to fix it.
      
      We still don't have the same behavior as in 2017.w25.
      I disabled channel simulation (so that UE RX = eNB TX)
      and I have one error where in 2017.w25 I have zero.
      For example, here comes the output of a run of "./dlsim":
      
      **********************SNR = 0.000000 dB (tx_lev 51.000000)**************************
      Errors (1(0)/1000 0/1 0/0 0/0), Pe = (1.000000e-03,0.000000e+00,-nan,-nan), dci_errors 0/1001, Pe = 0.000000e+00 => effective rate 99.900100, normalized delay 0.001472 (1.001000)
      
      And in 2017.w25 we have (with the same hack to disable
      channel simulation):
      
      **********************SNR = 0.000000 dB (tx_lev 51.000000)**************************
      Errors (0(0)/1000 0/0 0/0 0/0), Pe = (0.000000e+00,-nan,-nan,-nan), dci_errors 0/1000, Pe = 0.000000e+00 => effective rate 100.000000, normalized delay 0.001471 (1.000000)
      
      There may be a problem somewhere. Or there was one before and we should
      have had one error and the new UE architecture fixed things and now
      it's as it has to be. Hard to say at this point...
      
      When looking at the scope we quickly see some zeros for the PDSCH
      LLR, at the begining this time, not at the end. This is just when
      the GUI appears and then all is fine, so this seems to be for the
      first frame only. In 2017.w25 this does not happen.
      9e4f700a
  18. 01 Aug, 2017 1 commit
  19. 31 Jul, 2017 3 commits
  20. 28 Jul, 2017 1 commit
  21. 27 Jul, 2017 1 commit
    • Cedric Roux's avatar
      bugfix: fix bug "Unknown UE_id for rnti" · 8d5901c8
      Cedric Roux authored
      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
      8d5901c8
  22. 26 Jul, 2017 1 commit
  23. 25 Jul, 2017 2 commits
  24. 24 Jul, 2017 1 commit
  25. 20 Jul, 2017 1 commit
  26. 19 Jul, 2017 1 commit
  27. 17 Jul, 2017 3 commits