The downlink singalling failure counter DSC is decremented by 4
in case of unsuccessfull decoding of CCCH block and incremented
by 1 in case of successfull decoding of CCCH block. The initial
and maximum value of 90 requires to check the signal only once
per 51 multiframe.
If DRX would be supported, only a subset of 51 multiframes are
received, so the initial / maximum value of 90 must be reduced
accordingly.
As Dieter points out, this drastically improves the resiliance to high
receive levels on the C155. We cannot blindly assume a received signal
level of -85 dBm if the BTS is 2m away and we actually receive -40 dBm.
This patch extends the L1CTL_FBSB_REQ data structure in layer 1 with the
respective field, as well as the l1ctl_tx_fbsb_req() API function called
from the various layer23 apps.
"mobile" and "bcch_scan" already did a PM request and thus know the
expected signal power. "ccch_scan" and "cbch_sniff" apparently don't
do, so the -85 dBm constant is now hardcoded into the host-side source
code there, and should probably be fixed in a follow-up patch.
Since libosmocore already has LAPDm implementation, we don't need the
local copy of LAPDm code anymore.
Written-by: Andreas Eversberg <jolly@eversberg.eu>
Signed-off-by: Sylvain Munaut <tnt@246tNt.com>
This patch introduces cell re-relection. When camping on a cell, it
scanns neighbour cells. If a 'better' cell is found, the cell is selected.
If the cell is in a different location area, a location upating is
performed under certain conditions.
The 'better' cell depends on various informations that are broadcasted on
the BCCH of a neihbour cell and of course the RX level. Most operators
don't set these informations, so the 'better' cell depend on a better
RX level for the same location area, or a much better RX level (6 dBm)
at a different location area.
There were many issues at the idle mode process that has been fixed.
Expecially when moving, the state machines got stuck, so no more cell search
was possible, or no further calls / location updating was possible.
In order to see the process of cell selection, enter the VTY interface and
enable the network monitor:
enable
monitor network 1 (where '1' is the instance of the MS)
In order to see the current state of the processes, enter:
show ms
This patch changes include paths to get osmocom-bb working with
the current libosmocore tree.
Among all these renames, you can notice several tweaks that I
added on purpose, and that require some explanation, they are:
* hexdump() in osmocon.c and osmoload.c has been renamed to avoid
clashing with hexdump() defined in libosmocore.
* gsmmap now depends on libosmogsm. Actually I had to cleanup
Makefile.am because I was experiencing weird linking problems,
probably due to a bug in the autotools. With the change included
in this patch, I got it compiled and linked here correctly.
This patch has been tested with the phone Motorola C123 and the
following images files:
* firmware/board/compal_e88/hello_world.compalram.bin
* firmware/board/compal_e88/layer1.compalram.bin
Using the osmocon, bcch_scan and mobile tools.
Signed-off-by: Pablo Neira Ayuso <pablo@gnumonks.org>
There are two criterions for lossing a signal, idle mode and dedicated mode.
A counter counts down when a frame is dropped, and counts up when a valid
frame is received on certain channel. The loss criterion is reached, if the
counter reaches 0. The values added to / removed from the counter and the
limits depend on the process.
This is a quick workarround to make synchronizing to a cell more reliable.
Without it, just a few cells will sync. When network search is restarted, no
more sync happens. By increasing the freq_err_thresh1 to 10000, many cells
sync, even after the first network search.
The cell provides SYSTEM INFORMATION 5* and 6. These are used to create a
list of neighbor cells to monitor. Because there is no neighbor cell
monitoring supported by layer1, the list has no valid results yet.
Currently the average RX level of received frames are used to generate a new
report every second. The report is transmitted to layer1 and used there
whenever a measurement report has to be transmitted.
The timing advance and the current transmit power (as requested by network),
is included with every report.
The SIM client is now complete. Because it usefull for multiple
applications, i moved it to the layer23/src/common directory.
The SIM reader works together with mobile process. Fixes were made.
Thanx to all for testing, finding bugs, and making it work as it is
supposed to do.
The current version uses special L1CTL messages to send and receive APDUs.
This will change in the future, when BTSAP interface is completed.
Please note that this client will not work until the layer1 SIM reader
fixes and extensions are committed.
The layer23 will now set crypto mode and key when CIPHERING MODE COMMAND is
received. After crypto mode has been set, CIPHERING MODE COMPLETE is sent.
NOTE: Layer1 implements only the interface, there is no functionality to it
yet.
This commit features handling of ASSIGNMENT COMMAND. Currently only channel
descriptions "after time" are processed, which is mostly the case.
The ASSIGNMENT COMMAND is essential, because public networks assign an
SDCCH4/8 before actually assigning a TCH.
The interface between l1 and upper layer is called by several
name. IMHO l1ctl is shorted and sounds good so try to unify
using that.
Signed-off-by: Sylvain Munaut <tnt@246tNt.com>
This split the headers and adapt the source.
We use osmocom/bb as a prefix because libosomore also
uses osmocom and generic names such as misc & common could
conflict in the future.
Signed-off-by: Sylvain Munaut <tnt@246tNt.com>
We split into :
- common: Everything that can be shared
- mobile: The real spec compliant mobile phones
- misc: Different test stuff
Signed-off-by: Sylvain Munaut <tnt@246tNt.com>