Cellular Network Infrastructure » Radio Access Network » OsmoBSC

{{>toc}}

h1. Ericsson RBS 2000

There is some initial/experimental code in [[OpenBSC]] to support the Ericsson RBS 2000 family of BTS.

As opposed to Siemens/ip.access, Ericsson A-bis is much farther away from the specs, particularly

since their Organization and Maintenance Layer (OML) is a proprietary protocol called OM2000.

Nonetheless, we have been making quite a bit of progress in getting the RBS 2000 series supported.

Right now it is still not complete.  Don't expect anything to work at this stage.

We are collecting links to documents describing the Ericsson RBS architecture at [[RBS_Links]]

h2. Requirements

* Ericsson RBS 2000 series BTS

* E1 or T1 interface card, supported by the [[DAHDI]] driver. WE DO NOT SUPPORT RBS with mISDN drivers!

* RBS with software + IDB in default configuration, especially OML TEI set to 62

* /etc/dahdi/system.conf with "dslot=1,4" in it

h2. Setup

* Check that dahdi_tool is showing the link as OK, otherwise you have some wiring/polarity issues

* Create an openbsc.cfg that lists your BTS as 'rbs2000' type (see attached example)

** do not try to be clever and use non-standard E1 timeslot assignments, the code is hard-coded and assumes certain values

* start [[osmo-nitb]] as usual

* OM2000 messages can be decoded with Wireshark, set the following options:

** Right-Click on Link Access Procedure, Channel D (LAPD) ==> Protocol Preferences ==> Use GSM SAPI values

** Right-Click on GSM A-bis OML ==> Protocol Preferences ==> A-bis dialect to be used ==> Ericsson OM2000

h2. Status

So far, you should get

* A-bis link initialization, i.e. BSC telling the BTS to use TS1 as signalling for IXU/DXU OML

* [[OpenBSC]] configuring and starting the CF (central function)

* You can manually connect, configure and enable the IS via the VTY

* With some luck, the OML SAPI to the RRU/TRU's can then be established

* Using the '-p foo.pcap' option, you can write a PCAP protocol trace to be used with wireshark and our OM2000 wireshark dissector

What is NOT supported yet:

* Actually initializing the transceivers and Um timeslots

* Any actual communication with phones

* Any form of GPRS.  This requires us to implement a PCU compatible with the Ericsson PCU-CCU A-bis protocol. See [[Ericsson_RBS2000_GPRS]] for some collected information on this topic.