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Chaos Communication Camp 2011

At the CCC Camp 2011, we will again be running an experimental OpenBSC network.

The large area of the camp site and the number of users (expected in the 2,000 to 4,000 user range) make this an
ideal test installation for OpenBSC.

Netork structure

Given that there is only a maximum number of 10 ARFCN in the DECT guard band that we could use,
we cannot really afford to run many small BTSs. May small BTSs (single-arfcn) would mean that the capacity
is split/fragmented over the camp site.

Running few but large BTSs (many TRX) at higher power seems like the better strategy. It delivers
capacity without restricting it locally, i.e. capacity can be used anywhere on the camp.

License / Approval

We have a license from the German regulatory authority (Bundesnetzagentur) to operate on the following 6 ARFCN:

ARFCN Uplink Downlink Purpose
871 1782.0 1877.0 BTS 0 / TRX 0
873 1782.4 1877.4 BTS 1 / TRX 0
875 1782.8 1877.8 nanoBTS+booster
877 1783.2 1878.2 BTS 0 / TRX 1
879 1783.6 1878.6 BTS 1 / TRX 1
881 1784.0 1879.0 BTS 0 / TRX 2

The license covers ERP (Effective Radiated Power) of 5W on each of the ARFCN, on GPS coordinates within the Camp site, with antenna heights of up to 18m above ground for the duration of August 3rd through August 15.

Materials

BTS and accessories

There will be two BTSs:
  • BTS 0 with 3 TRX (Shelter 6)
    • Motorola MetroSite with 48V power requirement
    • Antenna pole will be fixed to the wall right of the right shelter door
    • Antenna cabling will go into the former battery room of the shelter via the ventilation outlets
    • BTS and 48V power supply will be inside the former battery room
  • BTS 1 with 2 TRX (Shelter 3)
    • Antenna pole will be welded to the outside of the right shelter door
    • BTS will be wall-mounted to the inside of the right shelter door
    • BTS will be powered directly from 230V AC mains
    • E1 cabling will go from this BTS to the former battery room of Shelter 6

Cabling

Antenna cabling will be H2000flex cable (2dB @ 10m / 2GHz).

E1 cabling will be CAT6 based for proper shielding against all the EMI on-site.

BSC and core network

We will run a single machine with DAHDI E1 cards and osmo-nitb attached to a lcr via MNCC.

This BSC machine will be located in the former battery room of Shelter 6, next to BTS1. E1 cabling will go from the BSC
to both of the BTS.

A dedicated Ethernet cable for administrative access will connect the BSC machine with the main tent of the GSM Village.

A dedicated Ethernet or E1 cable for Voice uplink will connect the BSC machine with the PoC phone switch.

Equipment availability

This is just a list of random equipment that we have at our disposal:

Harald

  • several nanoBTS 1800
  • 100m H2000flex cable
  • 20 N plugs for H2000flex
  • 6 7/16 to N adapters
  • 2 5dBi omnidirectional antenna (N-female)
  • 5 3dBi omnidirectional antenna (N-female)
  • various SMA-N pigtails and other adapters
  • 6 hybrid combiner/duplexer units from Horizon BTS (2x SMA PA in, 1x 7/16 Antenna, 1x N for Rx out)

Sylvain

  • 1 resistive combiner/splitter (up to 2w)
  • 1 duplexer board
  • 1 LNA + rx filter board
  • 2 duplexer + LNA + Rx filter boards

All SMA, all rated 3W max power. All 6V power supply

Dieter

  • 2 nokia BTS, each 2 TRX
    • no combiner / splitter / duplexer, i.e. 2x Tx out and 2x Rx in
    • E1 back-haul
    • OpenBSC code has been completed and tested with 2 TRX
    • need to be transported to Berlin, no good packaging, heavy

Thanks / Credits

We'd like to thank the following organizations and individuals for helping us:
  • FH Deggendorf for borrowing us two Nokia Metrosite BTS
  • Dieter Spaar for adding Nokia A-bis support to OpenBSC on short notice
  • NETZING AG for providing 5 GSM 1800 Antennas
  • sysmocom GmbH for providing antenna and E1 cabling, installation materials, the OpenBSC machine, etc.
  • Universität Freiburg for two nanoBTS boosters and two GSM 1800 omni antennas
  • Luftfahrtmuseum Finowfurt for providing the antenna poles and mounting them to the shelters
  • Bundesnetzagentur for giving us regulatory approval
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