Cellular Network Infrastructure » Radio Access Network » OsmoBSC

In order to support GSM-R ASCI, we'd need VGCS/VBS support.

In the BSC, this mostly means the following:

• definition of VBS/VGCS areas e.g. via VTY (or simply assume all areas are global in initial implementation)
• Abis: generation of RSL NOTIFICATION messages
• A interface / BSSMAP
  • VGCS/VBS SETUP + VGCS/VBS SETUP ACK + VGCS/VBS SETUP REFUSE messages
  • VGCS/VBS ASSIGNMENT REQ
  • UPLINK REQUEST, UPLINK RELEASE NOTIFICATION, UPLINK SEIZED COMMAND, UPLINK REQUEST ACK, UPLINK REJECT
  • VGCS ADDITIONAL INFORMATION

There's quite a bit of state machines and logic required.

• VGCS/VBS setup procedure
• VCGS/VBBS assignment proceure
  • procedures according to TS 48.008 section 3.1.21, 3.1.22
• handling of uplink related allocation and release procedures (VGCS)
• periodic NCH transmissions
• SACCH indications of NCH changes
• managing the bsc-colocated osmo-mgw
  • allocate a 'broadcast' endpoint with one sender and many recipients
  • RTP connections for each BTS
  • RTP connection to the MSC
  • modifying rcvonly/sendonly/sendrecv according to current talker setate (VGCS)