OpenBSC

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4246 discussions

MSC split out progress
by Holger Hans Peter Freyther 29 Jun '09

29 Jun '09

Hey, just a small head up. I rebased the holger/msc branch and also moved the mncc bits into the libmsc. I'm currently in Essen and should be able to test these patches tomorrow. One thing that keeps me from pushing (after having tested) is the following observation. For going from layer3 to layer4 we currently have a queue, for my patches when going from layer2 to layer3 I have a direct callback. Should I change that to use the same queuing approach? holger

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Re: AW: AW: BS/MS power summary
by Dieter Spaar 26 Jun '09

26 Jun '09

Hello Andreas, On Fri, 26 Jun 2009 10:38:54 +0200, "Andreas.Eversberg" <Andreas.Eversberg(a)versatel.de> wrote: > > i tested the suggested values: > > > NM_ATT_BS11_RADIO_MEAS_GRAN, 0x01, 0x05, > > NM_ATT_BS11_RADIO_MEAS_REP, 0x01, 0x01, > > no measurement reports during calls, never seen one before. maybe i have > the wrong firmware load? i also get errors after starting bsc-hack on > the lmt. i will try to load a different firmware this weekend. This is what I use: Safety Load: HS010876.SWL SW Load: HS011106.SWL Just one other thing, I am watching the measurement reports in custom E1 traces. I guess this should not care and bsc_hack will show them too. Best regards, Dieter -- Dieter Spaar, Germany spaar(a)mirider.augusta.de

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Some initial investigation on GPRS support
by Harald Welte 26 Jun '09

26 Jun '09

Hi! I've started to analyze GPRS and was actually even starting to write some code for it, but then have given up for the time being - it's much more work than anticipated. Given the long todo list of OpenBSC right now, I think I'll have put aside GPRS for some time :( Based on looking at protocol traces, I have figured out the nanoBTS GPRS/EDGE implementation roughly looks as follows: * make sure we allow the BTS to activate the GPRS software components in abis_nm / OML activation! * BTS will use a UDP connection on port 23000 for the GPRS related frames. The GSM specs will consider this type of connection between the PCU (part of the nanoBTS) and the SGSN. The establishment/configuration of the UDP port number and SGSN ip address has not yet been identified. Probably similar to how the RSL link is activated via OML. The protocol stack looks like: IP : UDP : NSIP : BSSGP : LLC : higher-layer IP and UDP you should know and/or not care about ;) NSIP is a IP-enabled version of NS as specified in TS 08.16 BSSGP is specified in TS 08.18 LLC is as specified in TS 04.64 the higher-layer depends on the SAPI value of the LLC and can be * GMM (GPRS Mobility Management as specified in 04.08) * User Data (actual IP packets, e.g.) * SMS So what is weird about this is that the GPRS MM is actually part of 04.08, but it is not terminated at the BSC but rather at the SGSN. Also, the deep stack comprised of many headers is really weird. Furthermore, it seems that a lot of the packet scheduling and timeslot allocation is happening inside the nanoBTS - very unlike the GSM side of things. I have not yet managed to figure out how to allocate/dedicate resources to GPRS.. after all, the BTS needs to know how many timeslots it can use for it, etc. If anyone wants to dig deeper, you're most welcome to do so. A list of relevant specs: 01.61 GPRS cipher algorithm requirements 03.60 Overall GRPS logical architecture (above RL and MAC) 03.64 GPRS radio interface 04.60 RLC/MAC on PDCH 04.64 MS-SGSN LLC spec (on top of RLC/MAC) 04.65 SGSN SNDCP 08.14 BSS SGSN Gb Layer 1 08.16 BSS SGSN Gb Layer 2 08.18 BSS SGSN BSS GPRS protocol 09.95 Interworking between modified PLMN supporting legacy GPRS and GPRS mobiles 22.060 GPRS Service Spec 23.060 GPRS Radio Service Spec 29.016 SGSN - VLR Interface Gs network interface spec 29.018 SGSN - VLR Interface Gs layer3 interface spec 29.060 GPRS Tunneling (GTP) over Gn and Gp Happy hacking, -- - Harald Welte <laforge(a)gnumonks.org> http://laforge.gnumonks.org/ ============================================================================ "Privacy in residential applications is a desirable marketing option." (ETSI EN 300 175-7 Ch. A6)

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AW: AW: BS/MS power summary
by Andreas.Eversberg 26 Jun '09

26 Jun '09

hi, i tested the suggested values: > NM_ATT_BS11_RADIO_MEAS_GRAN, 0x01, 0x05, > NM_ATT_BS11_RADIO_MEAS_REP, 0x01, 0x01, no measurement reports during calls, never seen one before. maybe i have the wrong firmware load? i also get errors after starting bsc-hack on the lmt. i will try to load a different firmware this weekend. regards, andreas

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Re: AW: BS/MS power summary
by Dieter Spaar 25 Jun '09

25 Jun '09

Hello Andreas, On Thu, 25 Jun 2009 11:16:58 +0200, "Andreas.Eversberg" <Andreas.Eversberg(a)versatel.de> wrote: > > thanx for the detailed description. i will try this out this weekend. i > will use a 900mhz radio receiver to check out the change in signal > strength. i cannot get any measurement reports yet. the change of > NM_ATT_BS11_RADIO_MEAS_GRAN value did not get me any measurement report > as before. Strange that you don't see the measurement reports. Here are the two attributes I use for the TRX attributes and they result in lots of reports when a channel is active (at least for a speech channel, for a location update there might be only one report because the connection is not active that long): NM_ATT_BS11_RADIO_MEAS_GRAN, 0x01, 0x05, NM_ATT_BS11_RADIO_MEAS_REP, 0x01, 0x01, I think I also tried it already with 0x02 to get a report every second. Best regards, Dieter -- Dieter Spaar, Germany spaar(a)mirider.augusta.de

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AW: BS/MS power summary
by Andreas.Eversberg 25 Jun '09

25 Jun '09

dieter, thanx for the detailed description. i will try this out this weekend. i will use a 900mhz radio receiver to check out the change in signal strength. i cannot get any measurement reports yet. the change of NM_ATT_BS11_RADIO_MEAS_GRAN value did not get me any measurement report as before. regards, andreas

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OpenBSC with 2.5G or 3G mobile devices support?
by Nordin 24 Jun '09

24 Jun '09

Hello guys, Has anybody registered a PDA phone of 2.5G/3G type to the BS11 bts succesfully? Cause I'm still struggling with it for my nanoBTS (1800 Mhz). Thank you.

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Which Pico cells are supported
by Waqas Farooq 24 Jun '09

24 Jun '09

Hi All, Can somebody please let me know which Pico cells can be interfaced with Open BSC? Any help or pointers will be be much appreciated. Thanks,

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Setting BS11 output power
by Eric Cathelinaud 24 Jun '09

24 Jun '09

Hi, I was following your mails about your results for the ouput power but I don't understand how you change it. I was checking the code but I didn't find how to change TX0 output power. I tried to change the line : abis_nm_bs11_set_trx_power(&bts->trx[0], BS11_TRX_POWER_GSM_30mW); with abis_nm_bs11_set_trx_power(&bts->trx[0], BS11_TRX_POWER_GSM_250mW); in the "create_objects" fonction but I don't know how the fonction is loaded, I don't know how the bs11 enter the state "BS11_STATE_WAIT_MIN_CFG_2" case BS11_STATE_WAIT_MIN_CFG_2: bs11cfg_state = STATE_SWLOAD; rc = create_objects(g_bts); break; If anyone can help me Thanks a lot Eric Cathelinaud

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BS/MS power summary
by Dieter Spaar 24 Jun '09

24 Jun '09

Hello, I try to give a short summary of the MS and BS power settings. It is not intended to replace the GSM specs, it just contains the important things for the current BS-11 configuration. MS power: - The MS power is usually specified as an absolute value, a lower value means higher power. Some values for GSM 900 (GSM 1800 has a different encoding): 15 -> 13 dBm (0.02 W) 10 -> 23 dBm (0.2 W) 5 -> 33 dBm (2 W) - The power used to access the RACH before any channel is active, is defined by a Cell Selection parameter in SYSTEM INFORMATION TYPE 3 and 4. Remark: bsc_hack currently uses "2" which should be increased (lower power) to avoid interference with the public networks. - When the BTS activates a channel, it sets the MS power. bsc_hack currently sets it to 15 which should be OK for testing (see rsl_rx_chan_rqd() in abis_rsl.c). - Dynamic power control of the MS power by the BTS is currently not enabled. BS power: - For the BS-11 the PA power can be configured to 0.03W, 0.08W, 0.25W or 2W (b11_config can be used for this purpose). - The attribute NM_ATT_RF_MAXPOWR_R of each TRX of the BS-11 can be set to a value from 0 (0dB) to 6 (12dB) to reduce the power in steps of 2dB (see bsc_hack.c). - for the TRX which carries the BCCH, there is no dynamic BS power control possible. In the meantime I have read at several places that the BCCH TRX has to use a fixed power and additionally cannot use a different ARFCN for example for the TCH (which also means that no hopping is possible). To use hopping or dynamic BS power control, the second TRX has to be used and configured in a way that it does not carry a BCCH. Best regard, Dieter -- Dieter Spaar, Germany spaar(a)mirider.augusta.de

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