OpenBSC

openbsc@lists.osmocom.org

16 participants
4247 discussions

RRLP [was: Problem connecting to NanoBTS with current version of OpenBSC]
by Dieter Spaar 23 Aug '10

23 Aug '10

Hello Andreas, On Sun, 22 Aug 2010 23:35:17 +0200, "Andreas Schmidt-Dannert" <aschmida(a)mail.tu-berlin.de> wrote: > > So bringing ms-assisted positioning to work is also a goal of me. > Is it not possible to just transfer the acquired data from the GPS > receiver in the MS to a A-GPS server in the network and let te server > compute the acquisition assistance data? Probably I am thinking to naive > here. I know it should be a server not too far away from the asking MS. My experience with two phones (BlackBerry, HTC with Qualcomm chipset) is that if the phone already has the position (for example because a GPS application is running on the phone) the phone will return the position without asking for assitance data. However if there is no position, they usually want the reference time, reference location and navigation model (ephemeris) as assitance data. One problem with this approach it that the size of those data are quite large (around 800 bytes in my tests) if they have to be transferred over a slow channel like the SDCCH during loacation update, so this slows done the location update considerable. Another problem which is most certainly related to the bad GSM receiver in my test phones is that it take very long to get a fix, even with the provided assitance data. In my experiments this was around 45 second, nearly the same time as getting a fix without any RRLP data. Of course there could be a problem with the assitance data so that getting a position takes that long. So I would like to try MS-assisted measurement where only a small amount of data has to be transferred to the phone. I don't know if the measurement will also be faster this way. I did not try it yet because the acquisition assitance data have to be calculated, for example you need the doppler shift of the satellite signal which has to be calculated from the satellite postition. Probably no "black magic" but I would prefer to have ready and tested code to avoid another source of possible errors (its a matter of time, I don't want to spent too much on it ;-). > By the way there was for a while a rrlp-ephemeris tree in openbsc. What > was it for and what happend with it? As i understood it one could > connect an external GPS device to a laptop to get data that is > needed..kind of an A-GPS server. Right? I don't know where the tree is now. Its from Sylvain, maybe he can tell you more. I used this code as a basis for my experiments. > Another tought: What about SUPL? > SUPL uses IP to get assistance data from a SUPL server...so maybe it is > possible to use a supl server from google or similar? I don't have much experience with it. I guess that you can get the other assitance data (e.g. ephemeris) this way. But I am not sure about the acquisition assitance data. Best regards, Dieter -- Dieter Spaar, Germany spaar(a)mirider.augusta.de

1 0

Problem connecting to NanoBTS with current version of OpenBSC
by Andreas Schmidt-Dannert 22 Aug '10

22 Aug '10

Hello all, till last Friday I was using a version of OpenBSC from around May. I used it on a machine with Fedora 13 and I had no problems at all. I am playing around with RRLP and since newer versions of OpenBSC also support packet data I wanted to upgrade to be able to receive A-GPS data from the internet. Anyway I am having problems getting it to work. Since Friday I am trying but without success and now I am really clueless and hope I will find some help here. First I installed it on a machine with Kubuntu 10.04 and I did the installation as recommended online for GPRS usage. The NanoBTS gets an IP adresse and I can configure it. After restart the led blinks slow and orange which means (after manual) the management link has not been establish. The slow blinking also occurred when I used the older version and there it worked so I guess the blinking can be ignored. However if I start bsc_hack it stops after the following: DB: Database initialized DB: Database prepared (hlr.sqlite3 exists afterwards) The debugging option did not reveal more information. Wireshark tells me that after DHCP there are no more packets coming from the NanoBTS. So even when I start bsc_hack there is no packet being transfered from OpenBSC to the NanoBTS....very strange. I thought it has something to do with firewall rules (under Fedora I had this problem) but I disabled everything and nothing happened. Then I thought maybe the problem is that I have installed OpenGGSN already and can now only start it when OpenBSC, osmo-sgsn and ggsn is configured and so I used my second machine (Debian Lenny) and installed only OpenBSC but I have the same problem there....the NanoBTS just keeps blinking slowly and orange. I do not think it is aproblem with the NanoBTS since it was still working on Friday. I reseted the NanoBTS several times, I gave it always around 2 or more minutes to connect and start (after starting bsc_hack) but it does not change anything. I guess it is a small problem but I just cannot see it. Maybe someone has a hint for me? Why are there no packets being exchanged? Sorry for the long mail but I wanted to explain it as detailed as possible so that the experts have it easier :) Thanks and Bye, Andreas

1 0

bts firmware
by Hans Witvliet 22 Aug '10

22 Aug '10

Hi all, Perhaps it's not appropiate to ask here (first post here).... I saw on the wiki the recipee how to upgrade a ipaccess nanobts with new firmware. Well, i can probably do some experimenting with a nanobts, but how do i get hold of more recent firmware? I know this nanobts was used in a proof-of-concept trial some years ago, and needed to be upgraded at that time. After the project ended, we had no more official contact with ipaccsess, so no chance in asking them for new firmware '-) >From what i heard, they cannot be used in a next project, as they were lacking some hardware features. So it would be fun if i do some experimenting at home. hw

2 2

BS11 and HFC-E1 Board for Sale
by Rene Stegmaier 21 Aug '10

21 Aug '10

Hi list, since i have access to a nanoBTS i didnt use the BS11 anymore... For sale is: Siemens BS-11 GSM900, Dual-trx, Power-cord and E1 Datacable CologneChip HFC-E1 Board The price for both is 550 Euro. The BS11 is located in 38518 Gifhorn (between Hannover and Wolfsburg) The original packaging of the BS11 is availibe so shipping is possible.

1 1

suggestion
by rajib saha 17 Aug '10

17 Aug '10

sir..my question is from e1_config.c....i want to know about the e1 configuration for bts,ts and trx in details..i have gone through the program but didnot understand it..so i need some theory about it..so please help

2 1

SUGGESTION
by rajib saha 16 Aug '10

16 Aug '10

SIR CAN U PLEASE GIVE THE THEORY OF E1 CONFIGURATION OF GSM..I.E.( BTS,TS AND TEI)..I M UNDERSTANDING THE CONFIGURATION FROM THE PROGRAM...PLS HELP

1 0

Avoid LCR-Stalling
by Konrad Meier 13 Aug '10

13 Aug '10

Dear List, At the moment I am building a GSM-Network with OpenBSC and three NanoBTS at the University of Freiburg. The purpose of this network is teaching and research. The Network has an ISDN BRI Interface which allows every gsm-phone to be called over a land line telephony number. We had huge problems with LCR-Stalling in our setup which lead to a increasing delay during a call (up to 6-10 seconds...). We could trace the problem to lookups in the database hlr.sqlite3. After some time the database was about 18MB big and it took some time to perform operations in the database. The quick solution was to copy the database to a RAM-Disk. A RAM-Disk can be created like this: sudo mount -t tmpfs -o size=300M tmpfs ramdisk After that, we never had seen stalling anymore. But this can only be considered as a quick hack because in case of a system failure all changes to the database are lost. Is someone at the moment working on a interface to a better database system? Maybe I find some student who can do this. Regards Konrad Meier

3 6

AW: Avoid LCR-Stalling
by Andreas.Eversberg 12 Aug '10

12 Aug '10

hi, it would make sense to run database lookup in a seperate thread (with lower priority). but in this case the database request function of openbsc will not have a result at the time they return. it would take some changes of the processes which do database lookups. i think it will be some work, but it can be done. regards, andreas

3 2

VTY Crash due an assumption we are breaking
by Holger Hans Peter Freyther 11 Aug '10

11 Aug '10

Hi all, I was debugging a crash with the VTY and I am not fully understanding it but I can easily reproduce it. The problem is triggered with the new VTY OML code and here is what I know. 1.) we move from ENABLE_NODE to the OML node. and allocate memory 2.) when exiting the node we will free the data at vty->index.. and set the pointer to NULL. But I can easily produce a double free issue and this seems to be due. cmd_execute_command: 1.) saves the vty->index to oindex and vty->node to onode 2.) tries calling vty_go_parent or such... 3.) tries more stuff... 4.) as stuff failed resets vty->index to oindex... so the next exit command will do a double free... and the funny part is that the code has one assumption everything > CONFIG_NODE is considered to be config as well. This means that we should have two enum values in libosmovty, one for Last_Enable, one for Last_Config and have enough space between them. And the other part... maybe vty_go_parent should return CMD_SUCCESS? thoughts? [1] ./script | telnet localhost 4242 and see the bsc_hack/bsc_msc_io crash

2 5

AW: Avoid LCR-Stalling
by Andreas.Eversberg 11 Aug '10

11 Aug '10

hi, what machine do you use? it smells like IDE harddisk. i also have IDE on a test system. better get rid of it. regards, andreas -----Ursprüngliche Nachricht----- Von: openbsc-bounces(a)lists.gnumonks.org [mailto:openbsc-bounces@lists.gnumonks.org] Im Auftrag von Konrad Meier Gesendet: Dienstag, 10. August 2010 15:56 An: OpenBSC list Betreff: Avoid LCR-Stalling Dear List, At the moment I am building a GSM-Network with OpenBSC and three NanoBTS at the University of Freiburg. The purpose of this network is teaching and research. The Network has an ISDN BRI Interface which allows every gsm-phone to be called over a land line telephony number. We had huge problems with LCR-Stalling in our setup which lead to a increasing delay during a call (up to 6-10 seconds...). We could trace the problem to lookups in the database hlr.sqlite3. After some time the database was about 18MB big and it took some time to perform operations in the database. The quick solution was to copy the database to a RAM-Disk. A RAM-Disk can be created like this: sudo mount -t tmpfs -o size=300M tmpfs ramdisk After that, we never had seen stalling anymore. But this can only be considered as a quick hack because in case of a system failure all changes to the database are lost. Is someone at the moment working on a interface to a better database system? Maybe I find some student who can do this. Regards Konrad Meier

2 1

Jump to page:

2026

2025

2024

2023

2022

2021

2020

2019

2018

2017

2016

2015

2014

2013

2012

2011

2010

2009

OpenBSC