Cellular Network Infrastructure » cni-legacy » OpenBSC

Implementation of E-UTRAN neighbor cell reporting via System Information 2 quater in OsmoBTS/OsmoBSC/OsmoNITB software including unit
tests and system test and fixing existing known SI2ter scheduling issues.

This includes

• Verifying existing SI2ter is scheduled, use something like osmo-bts + gsmtap to see that it is scheduled at the right frame
• bitvec for encoding the SI2 quater messages
• Scheduling (segmented) SI2 quater messages in osmo-bts
• VTY options to represent them. This is the most involved one so the actual interface and commands should be discussed.

OsmoBSC/OsmoNITB¶

• Extending SI3 to indicate presence of SI2quater
• Encoding of SI2quater messages with only the following optional parts (details see above):
  • Priority and E-UTRAN Parameters Description, containing
    • Serving Cell Priority Parameters Description
    • E-UTRAN Parameters Description, containing
      • Repeated E-UTRAN Neighbour Cells, with all their fields
      • Repeated E-UTRAN Not Allowed Cells, with all their fields
        • only implement the fixed single PCID (which can be repeated) encoding, not the bit-map / bit-masking encoding options
      • Repeated E-UTRAN PCID to TA mapping
• Implementing "fragmentation" of SI2quater over multiple messages with their respective Index/Count fields
• Sending SI2quater via A-bis RSL to the BTS

do not implement other elements, specifically not

• "E-UTRAN Measurement Parameters Description"
• "GPRS E-UTRAN Measurement Parameters Description"
• "Extended EARFCNs" (EARFCN > 65535)
• "MEASUREMENT INFORMATION" messages to instruct MS to provide measurement results for LTE while on GSM/GPRS
• "Fast Acquisition" with UTRAN_Start/UTRAN_Stop

OsmoBTS¶

• Fixing the existing SI2ter scheduling issues that may exist
• Implement receiving SI2quater via A-bis RSL, taking into account there mgiht be multiple fragmented messages with index/count
• Implement scheduling of SI2quater

Test Cases¶

• Implement unit tests for SI2qater encoding in BSC (part of "make check")
• Impement code that receives GSMTAP BCCH frames from OsmoBTS and verifies that only the correct expected SI messages occur at the right point in tme (FN / ...). This will be a separate program/tool, which hopefully we can later run together with osmo-bts-virtual as part of "make check", as the virtual BTS requires no real BTS hardware.