Be able to tune the RACH settings of the BTS via the vty interface,
by default they are initialized to -1 which means we will use the
content of the static array (BTS default) and can be changed via
the VTY interface. I have verified the setting on the nanoBTS with
wireshark and I have tested writing the config file.
For GSM V1 FR, the payload type is fixed to 3 in the RFC.
But for the other codecs, the payload type is dynamically assigned
between 96 and 127. Here, we use a static mapping internal to OpenBSC.
This patch is needed to make a rather old 139 unit (with sw version
120a002_v149b42d0) work with something else than FR codec. I also tested
this patch on a newer 139 (with sw version 120a352_v267b22d0) to make
sure it didn't add a regression. More testing with newer EDGE units
should be done by whoever has some of theses.
Signed-off-by: Sylvain Munaut <tnt@246tNt.com>
The current code was overly complex. It tried to iterate over
the list in a round robin and we had to keep track of the last
element, see if we remove that one, check if the list becomes
empty... This can all replaced by treating the double linked
list as a queue. We take the item at the front, do something
on it and then and then put it back to the list at the end.
This new gprs-conf branch is intended to contain everything needed
to configure GPRS in the nanoBTS, but without implementing the SGSN/GGSN
functionality.
The SGSN/GGSN development will happen in a branch based on this branch
called "gprs-sgsn"
This library is intended to collect all generic/common funcitionality
of all Osmocom.org projects, including OpenBSC but also OsmocomBB
The library currently includes the following modules:
bitvec, comp128, gsm_utils, msgb, select, signal, statistics, talloc, timer,
tlv_parse, linuxlist
msgb allocation error debugging had to be temporarily disabled as it depends on
'debug.c' functionality which at the moment remains in OpenBSC
Some NM attributes are defined differently depending on
the BTS type. Having one big nm_att_tlvdef[] table for
all BTS types is no longer sufficient. This patch
* introduces 'struct gsm_bts_model' to describe a BTS model
* adds definitions of gsm_bts_model for BS-11 and nanoBTS
* changes the abis_nm_tlv_parse() function: include a bts pointer
Theses will be useful to know if we can reuse the tuples or if
we should renew. The 'issued' is currently purely informative.
Signed-off-by: Sylvain Munaut <tnt@246tNt.com>
* On start the vty code will call the abis_nm method and this
will set the administrative state to unlock/lock
* During startup the BTS will report its state as well and would
possible overwrite the set administrative. We are only going
to update the administrative if it was 0 before. This appears
to work on all of my tests. In case this will not be the case
for others we will have to split the administrative into two
sets one for the BTS and one for the BSC.
In many cases we actually want a name / unique ID for the lchan,
not just for the on-air timeslot... especially in SDCCH/8 case,
where 8 SDCCHs share one timeslot...
When we allocate a channel, we send the RSL CHAN ACT REQ and wait until we get
a CHAN ACT ACK. Only the ACK will change the state, so there is a race where
we allocate that same channel to a different channel request before we get
the ACT ACK.
Introducing a new ACT_REQ state resolves this issue.
This has the advantage that counters can be added all over the code
very easily, while having only one routine that stores all of the
current counter values to the database. The counters are synced
every 60 seconds, providing relatively fine grained statistics
about the network usage as time passes by.
This implements the handover algorithm (and associated parameters)
as described in Chapter 8 of the book "Performance Enhancements in
a Frequency |Hopping GSM Network" by Thomas Toftegard Nielsen and Jeroen
Wigard.
The parameters such as averaging windows are configured in struct
gsm_network. We keep some state to trakc up to 10 neighbors as
they are being reported from the MS.
This has so far only been tested in a network with two BTS that
have each other as neighbor. Networks with morge neighbors might
encounter bugs.
This allows us to block packets that we have received after the channel
is no longer being used. This is visible during handover, where we still
receive a measurement report after the MS has switched to the new channel.
This leftover measurement report then attempts to trigger another handover,
which si bogus and will fail - and thus only consumes resources.
With the new LCHAN_S_ACTIVE state, we can check for this when processing
the measurement report.
We will need this for the actual handover algorithm implementation, as we will
only know the current BTS and the BCCH ARFCN of the strongest cell in the
measurement reports. Using this new function, we can resolve the matching
gsm_bts.
We use a 1024-bit-sized bitvec to generate the BA and neighbor frequency list.
This bitvec is still generated from the list of all BTS's inside the BSC, but
this patch is the first step to generalize this, i.e. generate arbitrary
neighbor lists.
Harald Welte
Holger Hans Peter Freyther
Sylvain Munaut