We now count the total number of RACH slots, the number with rx level
above the busy threshold, and the number of valid access bursts.
This data is used to generate RSL CCCH LOAD INDICATION for the RACH.
We now implement the fairly complex rules for schedulign of
SI 2bis/2ter/2quater, 13 and 9 on TC=4 and TC=5 of the BCCH Norm.
The patch is currently untested.
Send the RSL ACT ACK/NACK after the Layer1 firmware has acked the
activation/deactivation. In case the channel can not be activated
we will send a NACK. In case the channel can not be deactivated we
will send an ACK and the next time the channel is activated we will
send a NACK. The release ack will be sent once the TxDownlink of the
TCH/SDCCH is closed.
Change the rsl_tx_chan_nack method to create a new msgb to be used
by the hardware layer, change the return value to ask the caller to
delete the msgb.
We now check if the received message is an LAPDm I frame in order to
determine if we have received the first valid encrypted message on the
radio link. This relates to the fact that we often see 'old' UI frames
coming up from L1, even after it has confirmed decryption has been
enabled.
Using osmo-bts-sysmo and this code, it is now possible to do FR and AMR
based voice calls on TCH/F.
A lot of CPU is wasted in the conversion between the RTP formats and the
L1 specific formats for the codec frames. All data needs to be shifted
by four bits, and the order of bits needs to be reversed in every byte.
This only implements creating, binding, connecting and free'ing RTP
sockets, not yet anything regarding receiving or transmitting codec
frames on them.
You will need the rtp branch of libosmocore for libosmotrau
The sequence is as follows:
0) start osmo-bts
1) start connection attempts to BTS
2) issue L1-RESET.req
3) receive L1-RESET.conf
4) issue RF-ACTIVATE.req
5) receive RF-ACTIVATE.conf
6) receive attributes for TRX
7) receive opstart for TRX
8) issue MPH-INIT.req
[...]
The important point here is: We don't want the BSC to set TRX attributes or do
TRX opstart before our RF related hardware is initialized.
* gather measurements from each PH-DATA.ind
* check every TDMA frame about meas period expiration
* compute averages after period expired
* put MS DL MEAS REP into RSL MEAS RES messages, include UL meas
bugs:
* L3 INFO content seems to have some offset
* is_sub is not set anywhere
* measurement periods might have up/downlink offset
This code re-works osmo-bts to add support for the upcoming sysmocom BTS.
It also tries to add some level of abstraction between the generic
part of a BTS (A-bis, RSL, OML, data structures, paging scheduling,
BCCH/AGCH scheduling, etc.) and the actual hardware-specific bits.
The hardware-specific bits are currently only implemented for the sysmocom
femtobts, but should be (re-)added for osmocom-bb, as well as a virtual
BTS for simulation purpose later.
The sysmocom bts specific parts require hardware-specific header files
which are (at least currently) not publicly distributed.
Andreas Eversberg
Harald Welte