This commit introduces a 'basic simulator'.
This basic simulator is made of:
- the standard eNB code using a special driver that mimics the USRP driver
- the standard UE code using a special driver that mimics the USRP driver
- no channel simulation
- some special code to deal with faster-than-realtime behaviour of this
basic simulator
It connects one UE to one eNB. It requires an EPC, populated with the
correct configuration for the UE.
This is the initial release and may contain bugs (most probably race
conditions due to the faster-than-realtime behaviour).
To use it, see the documentation at:
targets/ARCH/tcp_bridge/README.tcp_bridge_oai.
It has been tested with 25, 50 and 100 RBs, FDD mode.
(No check at all has been done to know if it could work in TDD mode.)
- fix compilation of dlsim/ulsim/oaisim by defining some needed
global variables
- fix compilation of oaisim: compile coding and params_libconfig
- fix running of if4p5 with low CPU count (oaisim was not working
on the machine 'haswell' because of this)
It is possible to restart the lte-softmodem via the FlexRAN controller. For
this to work, the end_configmodule() method needs to be called when shutting
the lte-softmodem down so that the configuration can be read again during a
restart.
When the program exits it has to stop the streaming of the USRP.
The function exit_fun is supposed to do that. When quitting with
control+c (very common case) this function is not called. The
code is very unclear there, so let's add a stop_rf in the RU,
as there is already a start_rf.
If we don't call trx_end_func, then at the next run the USRP
device may be in an unstable state and behave improperly.
If the program crashes then the USRP device may be in an
unstable state. The only solution to this problem is to reset
the USRP device.
Maybe there is a way to clean the state of the device when we
open it, before we start using it. Sort of a cleanup before
use. That could be a better solution to "bad state after program
crash".
What has been tested:
- monolithic eNB only
The one in lte-enb.c disrupts the realtime. Using a B200mini with
20MHz bandwidth leads to the UE unable to connect for it seesms like
the UL and DL are not properly time synched because of this sleep
of one second that happens after the USRP streaming has started.
We see some random access attempts but the decoded preamble is
wrong.
This may be dependant on the setup. I had sporadic errors with
a B210, where sometimes the UE could connect and sometimes not.
'_' is not a valid character.
S1AP specs say:
ENBname ::= PrintableString (SIZE (1..150,...))
And X.680 (08/2015) 41.4 table 10 lists the valid characters for
PrintableString. '_' is not there. We replace by '-' which is there.
Connection of eNB to ppenair-cn has not been tested. There is no reason
why it would fail.
Cedric Roux