During development one switches from GSM900 to GSM1800 and GSM850 to
GSM1900. This commit attempts to make this switch more easy.
GSM1800 and GSM1900 have overlapping ARFCNs. This means that the
mapping from bands to arfcn is not injective. Because of that I
removed the code to deduce the band from the ARFCN. This was done
in commit 8c3d807b3f. The auto-band
option allows to move between GSM900/GSM1800 and GSM850/GSM1900.
Add a simple testcase with these auto-band configurations.
Chapter 5.2 applies to MS procedure, but 5.3 (BSS procedure) defines no
exact criterion, so I decided to use the procedure equivalent to MS.
The criterion is based on a counter S, which is initialized to a preset
RADIO_LINK_TIMEOUT, which can be configured via VTY. Whenever a received
SACCH block is bad, S is counted down by one. If SACCH block is
successfully decoded, S is counted up by two, but never above initial
RADIO_LINK_TIMEOUT value. If S reaches 0, an RSL Connection Failure
Indication with cause RF Radio Link Failure is sent to BSC, which then
aborts channel.
Use link timeout value from BSC via OML attribute.
How to test:
- Set "debug" for "meas" logging.
- Start silent call to an attached mobile.
- Remove battery from mobile or shield mobile.
- Watch S count down.
Instead of explicitly having to specify the local IP address for RTP
sockets in the BTS, we just use "0.0.0.0" instead, which gets
translated to INADDR_ANY.
We still accept the configuration directive in old config files, but
when we write, the line will no longer be re-written to the file.
TODO: IMHO, the IPA RSL CRCX/MDCX actually permit the BSC to specify the
IP address on the BTS side, and we probably simply ignore this at this
point.
These attributes are saved in paging_state, we don't need to save them a
second time in struct gsm_bts_role_bts. Add get and set methods for
these attributes and use them consitently in the VTY code.
This was found and debugged by Sylvain. The BTS will always support
A5/0 so we do not keep track of that, the first bit of the flags is
used for A5/1, second for A5/2... but for RSL there is an offset to
go from RSL to A5(x). Add a testcase and change the code.
Right now osmo-bts requires access to one OpenBSC header file and
this requires that openbsc and osmo-bts git are in the same directory.
Begin with making the location of the OpenBSC sourcecode configurable.
This approach will allow to build osmo-bts on our Jenkins installation
but now has the risk of more code including the openbsc/*.h header files.
This may be adding bells and whistles that nobody wants to touch, but at
least for current analysis/optimiziation they are useful to have. Later
on they should probably be removed again and/or obsoleted by OML
messages for configuration of paging behaviour by the BSC.
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.
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.
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.
Holger Hans Peter Freyther
Harald Welte