This commit introduces several enhancements in X2AP and RRC to deal
with ENDC. The main goal is to deal with UE's on/off and with various
errors.
The following work is included:
- DC prep and DC overall X2 timers
- X2 messages for UE release and DC timers' timeout
Open problems:
- what to do when the UE sends an scg Failure? This commit removes
the UE. And this removal may not be correctly done
- UE removal in the gNB's PHY layer (a next commit is coming,
but it is hackish and will need a rework)
In the configuration file, to enable measurements, add:
enable_measurement_reports = "yes";
Note that if x2 is enabled then the option 'enable_measurement_reports'
is not taken into account and the measurements are enabled.
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.