Nokia InSite configuration check

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Sipos Csaba dchardware at gmail.com
Sun Jun 30 19:14:14 UTC 2013


Dear members,

In connection with the problem I found, I kindly ask someone, to
please check my configuration, because I want to rule out any
configuration related issue, don't want to waste anyones time with
sending false bug reports.

Currently I am using a GSM1800 Nokia InSite unit with a Dahdi E1 card
and OpenBSC, the DAHDI card is the timing source.

/etc/dahdi/system.conf

span=1,0,0,ccs,hdb3,crc4
bchan=2-31
dchan=1

OpenBSC conf:

password foo
line vty
 no login
e1_input
 e1_line 0 driver dahdi
network
 network country code 1
 mobile network code 1
 short name OpenBSC
 long name OpenBSC 
 mm info 1
 timer t3101 10
 timer t3113 60
 bts 0
  type nokia_site
  band GSM1800
  cell_identity 1
  location_area_code 1
  base_station_id_code 63
  training_sequence_code 7
  ms max power 40
  periodic location update 10
  
  oml e1 line 0 timeslot 5 sub-slot full
  oml e1 tei 1
  
  trx 0
   arfcn 885
   nominal power 22
   max_power_red 0
   rsl e1 line 0 timeslot 4 sub-slot full
   rsl e1 tei 1


    timeslot 0
     phys_chan_config CCCH+SDCCH4
     e1 line 0 timeslot 2 sub-slot 0

    timeslot 1
     phys_chan_config TCH/F
     e1 line 0 timeslot 2 sub-slot 1

    timeslot 2
     phys_chan_config TCH/F
     e1 line 0 timeslot 2 sub-slot 2

    timeslot 3
     phys_chan_config TCH/F
     e1 line 0 timeslot 2 sub-slot 3

    timeslot 4
     phys_chan_config TCH/F
     e1 line 0 timeslot 3 sub-slot 0

    timeslot 5
     phys_chan_config TCH/F
     e1 line 0 timeslot 3 sub-slot 1

    timeslot 6
     phys_chan_config TCH/F
     e1 line 0 timeslot 3 sub-slot 2

    timeslot 7
     phys_chan_config TCH/F
     e1 line 0 timeslot 3 sub-slot 3

My main concern is about the OML and RSL TEI addresses.

If I understand it correctly, OML TEI identifies the BTS, RSL TEI
identifies the TRX of that BTS. So if I have 2 BTSs and 2-2 TRXs, then
the correct configuration would be looking like this:

BTS0:
    oml: te1 1
    trx0: tei 1
    trx1: tei 2
    trx2: tei 3
    ....
BTS1:
    oml: tei 2
    trx0: tei 1
    trx1: tei 2
    trx2: tei 3
    ...

?

Even the Nokia BTS commissioning documentation is unclear about the
specifics:

sapi =Service access point identifier. (62 for OMUSIG, 0 for TRXSIG.)
tei =Terminal end point identifier. Must the same as defined in the BTS.
Usually the same as the TRX number. For OMU link, the value is 1.

According to this, every OML TEI of every BTS should be "1" ? The
other funny part is, that it sais it must be the same as defined in the
BTS, but Nokia BTS Manager does not have any parameter for TEI or SAPI
to set.

My other concerns are BSIC and Training Sequence Code (TSC).

As I know, BSIC identifies the BTS in a location and/or routing area,
it means that a location/routing area can have 64 BTSs at top
(BSIC=0-63), and every BTS have to use unique BSIC in the same LAC?

TSC is another mystery. Nokia Docs sais:

train_seq = Training sequence code. (eg. BCC value of the BSIC, eg. 7)

This has to be 7 all the time, or if I have more than one BTS (in the
same LAC and on the same E1)I have to change this?

Finally, DAHDI configuration:

How many D channels should I specify? For example if I have 2 BTSs on
the same E1, I have to specify two D channels for every OMUSIG
timeslots? Or I have to specify D channels for every timeslots I use
for signalling (OMUSIG and TRXSIG for all BTSs)? Or maybe I don't have
to allocate even one D channel, because I dedicate separate signalling and TCH
timeslots for every BTS?

I searched a lot about this topic, but the information available is
limited, not specific and most of the time lead to more questions...

I hope someone can enlighten me in this topic.

BR,
Csaba









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