Using TDMA frame number of a burst with bid=0 is fine for xCCH,
but not for TCH and FACCH, because they use the block-diagonel
interleaving. A single block on TCH may be interleaved over
8, 4 or even 6 consecutive bursts depending on its type.
Since we now have the measurement history, we can attach TDMA
frame number to each measurement set, and then look up N-th
one when averaging the measurements in sched_trx_meas_avg().
Change-Id: I9221957297a6154edc1767a0e3753f5ee383173f
So far we used to store the sums of ToA and RSSI measurements in the
logical channel state, and after decoding of a block, we did calculate
the average. This approach works fine for xCCH and PDTCH, but when it
comes to block-diagonal interleaving (which is used on TCH/F and TCH/H
channels), the results are incorrect. The problem is that a burst on
TCH may carry 57 bits of one encoded frame and 57 bits of another.
Instead of calculating the sum of measurements on the fly, let's push
them into a circular buffer (the measurement history), and keep them
there even after decoding of a block. This would allow us to calculate
the average of N last measurements depending on the interleaving type.
A single circular buffer can hold up to 8 unique measurements, so the
recent measurements would basically override the oldest ones.
Change-Id: I211ee3314f0a284112a4deddc0e93028f4a27cef
The existing logic unconditionally wants to send a POWERON command
on TRXC whenever L1CTL_FBSB_REQ is received. That may cause some
problems when sending subsequent L1CTL_FBSB_REQ, e.g. due to signal loss.
Sending POWEROFF when transceiver is not powered on is normal though.
This can happen if trxcon is restarted while fake_trx was running.
The existing FSM state could unfortunately not been used, as it's a
mixture between the TRX connection state and the command/response state.
The current solution is just a work around. We definitely need to
introduce separate state machines for transceiver and its TRXC
interface.
Change-Id: I834e8897b95a2490811319697fc7cab6076db480
According to the man page of recv(), the only difference of this
call from read() is the presence of flags. With a zero flags
argument, recv() is generally equivalent to read().
Change-Id: I6d43bbf8d52c5fbb8ee0592b7d1c1dfd2dd1548e
The main changes are:
- return pointer to the allocated trx_instance or NULL,
- extend debug message with TRX address and base port,
- accept the talloc context as 'tall_ctx' argument,
- rename goto label 'error' to 'udp_error',
- rename argument 'port' to 'base_port'.
Change-Id: I39b24afee2f09d6a6c500cfc26ac45f206589c5c
The idea of SETFH command is to instruct transceiver to enable
frequency hopping mode using the following parameters:
CMD SETFH <HSN> <MAIO> <CH1> <CH2> [... <CHN>]
Note: since the length of a CTRL command is limited to 128
symbols (BTW: why?), the amount of channels is also limited.
Change-Id: Id3d44e6a2796f1ce8523a49dedd5d484052a5c7f
Despite the correct range of Timing Advance value is [0..63],
there is a special feature in OsmocomBB which allows one to
simulate the distance between both MS and a BTS by playing
with the signal delay.
This is why a signed 'int8_t' type is used in L1CTL protocol.
No need to limit the range, just forward it to TRX.
Change-Id: I06774b315b8451bf14083da6b2849d6e8594abc8
I am not sure we need the both control commands, as every burst
on DATA interface has a header that includes TX power.
Change-Id: Id14603e71df6dedb5a843bb3e20a320192dbca3d
In the most cases an ARFCN value is stored together with some
flags (e.g. DL/UL flag, DCS flag), so it should be taken into
account e.g. when printing. Let's use the proper naming.
Change-Id: I0b7634c80986dbff9d0da421c6a044cd36c9fd01
There's no need to express ToA value as a float. Let's turn it into
an int16_t with 1/256 symbol period accuracy throughout the code to
avoid both float arithmetic as well as loosing any precision.
Inspired by Idce4178e0b1f7e940ebc22b3e2f340fcd544d4ec.
Change-Id: I99c0f38db08a530d5846c474aba352aa0b68fe86
The command line help states '-i' is for 'TRX IP address', which is
the remote IP address at which the TRX is to be found. Hoewever, it
was used as the local (bind) IP address of the socket used towards
the TRX. This is my attempt at fixing this. A more complete solution
probably allows to specify both local (bind) and remote (connect)
address, just to be clear.
Change-Id: If0252b15e9c7942687c6dc470951d777f7af651c
The time at which the phone is allowed to transmit a burst of
traffic within a timeslot must be adjusted accordingly to prevent
collisions with adjacent users. Timing Advance (TA) is the
variable controlling this adjustment. The TA value is normally
between 0 and 63, with each step representing an advance of
one bit period (approximately 3.69 microseconds).
As trxcon doesn't perform actual burst transmission, this value
needs to be forwarded to the transceiver, which will take care
about the timings.
Change-Id: Ia8c0848827ab2b4cd7cf1efe128b28d5c06ec84e
The 'SETMAXDLY' command is used on the BTS side to limit maximal
Time of Arrival for access bursts. As we don't receive RACH
bursts on the MS side, the command is useless.
The 'SETRXGAIN' command is used on the BTS side to set initial
receive gain value for TRX. On the MS side it's possible to set
that parameter via command-line options of TRX.
Change-Id: I3e61b4b48193004cdcb241cefabb44c12db93120
Since 8c4f5457 in libosmocore there are some limitations on FSM
and FSM instance names. This change adjusts the names of both
l1ctl_fsm and trx_fsm instances.
Change-Id: Icaaac3f51bdcfe4f7723060179b8730c3a06529b
There is no (performance) reason to use fprintf instead of LOGP.
Second one provides more useful information, such as a file name
and a line number.
Change-Id: I86dda5b3d746c7802442e4226578a06c04941721
Local clock counter can be corrected using frame number values,
obtained from burst header on DATA interface.
Change-Id: I5a813e3dc1b960831343b8ecb80718291f20e80d
Previously, we had both length and string matching of request and
response. To be able to implement commands with additional params
in the future, this change drops the length matching part.
Change-Id: Id4c50115f5f1b1da450ff8b8dcfd6ccf572d23f5
For some reasons, OsmoTRX sends 158-byte long sequences on DATA
interface, where the latest two bytes aren't used.
Change-Id: Ie9295e9b0d8956d9e87e2ced8cca9d5e68040f88
This change introduces the following state machines:
- trxcon_app_fsm - main application state machine.
This state machine handles different events, raised
from program modules (such as trx_if.c or l1ctl.c).
- l1ctl_link_fsm - L1CTL server state machine.
- trx_interface_fsm - TRX interface state machine.
The program modules (such as trx_if.c or l1ctl.c) should be as
much independent from each other as possible. In other words,
one module should not call methods from another, e.g. L1CTL
handlers are not able to send any command to transceiver directly.
Instead of that, they should use shared event set to notify the
main state machine about something. Depending on current state
and received event, main state machine 'decides' what to do. This
approach would allow to easily reuse the source code almost 'as is'
anywhere outside the project.
Change-Id: I7ee6fc891abe5f775f5b7ebbf093181a97950dea
This is the second side of the 'OsmocomBB <-> SDR' bridge.
Most of source code taken from the OsmoBTS project.
Change-Id: I96fa3ada05d010f31af419a4950fd8ae2b62ef34
Vadim Yanitskiy
Harald Welte