This parameter is meaningful in TDD, to decide
when to start DL at eNB side. Since there is a
need for the PA to be operational, we need to
transmit a bit before the DL subframe coming
after an UL subframe. (We transmit zeros.)
We used to use N_TA_offset which may be too much.
Default value is now N_TA_offset/2 and can be
changed in the configuration file, in the RUs
section, like:
RUs = (
{
local_rf = "yes"
nb_tx = 1
nb_rx = 1
att_tx = 0
att_rx = 0;
bands = [7];
max_pdschReferenceSignalPower = -27;
max_rxgain = 105;
eNB_instances = [0];
sf_extension = 312;
}
);
N_TA_offset is 624 (for 30.72MHz). In the example
above, we set sf_extension = 312, which is also
the default.
The value to put in the configuration file is for
30.72MHz. The value is scaled accordingly at runtime
(thus only one value to set for every RB configuration,
25, 50 or 100, leading to less problems when adapting
configuration files).
This option is for experts and should not be changed
randomly.
This commit introduces X2AP timers (t_reloc_prep, tx2_reloc_overall).
You need to set the values in the configuration file.
X2AP can be enabled or disabled in the configuration file too (disabled
by default).
Some deadcode was removed.
With the introduction of X2AP into develop, the UEs now have to regularly
send measurement reports.
In the logs of the eNB, we see:
[OSA] Mismatch found in integrity for algorithm 2,
got e0.a0.c2.66, expecting a5.9c.cb.57
[PDCP] [OSA][RB 1] eNB failed to validate MAC-I of incoming PDU
This is a bug in the PDCP layer that uses wrong parameters to compute the
integrity.
This commit fixes this bug.
The function pdcp_is_rx_seq_number_valid was removed. Its processing
has been directly integrated into the function pdcp_data_ind.
The function pdcp_mark_current_pdu_as_received is not called anymore.
Its processing was not used later on, so as of today, not calling it does
not introduce any functional change.
The function pdcp_validate_security takes now as parameters both
SN and HFN. Same for the function pdcp_get_next_count_rx.
Useless constants PDCP_SN_5BIT, PDCP_SN_7BIT and PDCP_SN_12BIT have been
removed.
The compilation option ENABLE_SECURITY has been removed. It's now always
on. (This may impact some use cases.)
The PDCP for DRB using RLC AM is not correct. It was not correct before
this commit (apart from the integrity bug). We should deal with a list
of PDUs and transmit packets to upper layers as detailed in the specs.
Today we transmit the PDU as soon as we get it. We don't care about
duplicates, in-order delivery, timeouts.
Also, we don't deal with "PDCP re-establishment". Not sure how that impacts
the software.
And, last but not least, there is still no ROHC.
--> openair2/LAYER2/MAC/eNB_scheduler_primitives.c is still old (not from issue394_fix_cppcheck branch)
Signed-off-by: Raphael Defosseux <raphael.defosseux@eurecom.fr>
Due to some unknown bug in the eNB (or UE, or both), the first frames
are not correctly generated (or handled), which leads to a bad behavior
of the simulator in some cases (seen with 100 RBs: the UE reads a bad
MIB and switches to 25 RBs, which results in a deadlock in the
tcp_bridge_oai driver).
Let's "fix" this problem by skipping (in the driver) some frames at the
beginning of the simulation.
Cedric Roux