Messages on DATA interface may have different header formats, defined
by a version number, which can be negotiated on the control interface.
By default, the Transceiver will use the legacy header version (0).
The header format negotiation can be initiated by the L1 using the
'SETFORMAT' command. If the requested version is not supported by
the transceiver, status code of the response message should indicate
a preferred (basically, the latest) version. The format of this
message is the following:
L1 -> TRX: CMD SETFORMAT VER_REQ
L1 <- TRX: RSP SETFORMAT VER_RSP VER_REQ
where:
- VER_REQ is the requested version (suggested by the L1),
- VER_RSP is either the applied version if matches VER_REQ,
or a preferred version if VER_REQ is not supported.
If the transceiver indicates VER_RSP different than VER_REQ, the L1
is supposed to reinitiate the version negotiation using the suggested
VER_RSP. For example:
L1 -> TRX: CMD SETFORMAT 2
L1 <- TRX: RSP SETFORMAT 1 2
L1 -> TRX: CMD SETFORMAT 1
L1 <- TRX: RSP SETFORMAT 1 1
If no suitable VER_RSP is found, or the VER_REQ is incorrect,
the status code in the response shall be -1.
As soon as VER_RSP matches VER_REQ in the response, the process
of negotiation is complete. Changing the header version is
supposed to be done before POWERON, but can be also done after.
Change-Id: I8d441b2559863d2dbd680db371062e4f3a2f9ff9
Related: OS#4006
Since fake_trx.py can handle multiple transceivers, it makes sense
to print some info in logging messages about transceivers they
belong to. This acvieved by defining __str__() for Transceiver.
Some examples:
[DEBUG] ctrl_if_trx.py:83 (127.0.0.1:5700) Recv POWEROFF cmd
[INFO] ctrl_if_trx.py:85 (127.0.0.1:5700) Stopping transceiver...
[DEBUG] ctrl_if_trx.py:95 (127.0.0.1:5700/1) Recv RXTUNE cmd
[DEBUG] ctrl_if_trx.py:102 (127.0.0.1:5700/1) Recv TXTUNE cmd
[DEBUG] ctrl_if_trx.py:155 (127.0.0.1:5700/1) Ignore CMD SETTSC
[DEBUG] ctrl_if_trx.py:155 (127.0.0.1:5700/1) Ignore CMD SETPOWER
Change-Id: I1f706790a2da226f1418f89d2cfbb55baa6ea624
This change is a big step towards handling of multiple transceivers
in a single process, i.e. multiple MS and multiple BTS connections.
The old class hierarchy wasn't flexible enough, because initially
fake_trx was designed as a bridge between OsmocomBB and OsmoBTS,
but not as the burst router. There were two separate, but 90%
similar implementations of the CTRL interface, two variations
of each simulation parameter - one for UL, another for DL.
The following new classes are introduced:
- Transceiver - represents a single transceiver, that can be
used as for the BTS side, as for the MS side. Each instance
has its own CTRL, DATA, and (optionally) CLCK interfaces,
among with basic state variables, such as both RX / TX freq.,
power state (running or idle) and list of active timeslots.
- CTRLInterfaceTRX - unified control interface handler for
common transceiver management commands, such as POWERON,
RXTUNE, and SETSLOT. Deprecates both CTRLInterface{BB|BTS}.
- FakeTRX - basically, a child of Transceiver, extended with
RF path (burst loss, RSSI, TA, ToA) simulation. Implements
a custom CTRL command handler for CTRLInterfaceTRX.
The following classes were refactored:
- BurstForwarder - still performs burst forwarding, but now
it doesn't store any simulation parameters, and doesn't
know who is BTS, and who is MS. Actually, BurstForwarder
transforms each L12TRX message into a TRX2L1 message, and
dispatches it between running transceivers with matching
RX frequency and matching timeslot.
- FakePM - still generates random RSSI values, but doesn't
distinguish between MS and BTS anymore. As soon as a
measurement request is received, it attempts to find
at least one running TRX on a given frequency.
Please note that fake_trx.py still does handle only a single pair
of MS and BTS. No regressions have been observed. Both new and
refactored classes were documented.
Change-Id: Ice44e2b22566b3652ef6d43896055963b13ab185
Related: OS#3667
Alexander Couzens