ENHANCED MEASUREMENT REPORT
We don't support this yet, neither the associated Bter frame format
Whether or not this message is needed is primarily dependent on whether
the BSC instructs the MS to use ENHANCED MEASUREMENT REPORT.
The same topic exists with EXTENDED MEAUSUREMENT REPORT / EXTENDED
OsmoBSC / OsmoNITB use neither, so it is not a requirement to OsmoBTS,
unless you want to use it with a different BSC.
- 3GPP TS 45.008 version 13.0.0 Release 138.4.8 Enhanced Measurement Reporting
- 3GPP TS 44.018 version 10.3.0 Release 10:
- 18.104.22.168 Measurement Report and Enhanced Measurement Report
- 9.1.55 ENHANCED MEASUREMENT REPORT
- REPORTING_QUANTITY (6 bits): Measurement quantities are defined in 3GPP TS 45.008 (6 bits, it's actually RXLEV for GSM AFAIU).
- BSIC Description, see sub-clause 22.214.171.124.1.2 ("Deriving the GSM Neighbour Cell list from the BSICs and the BA (list)").
Further interesting short snippets from spec summarizing the feature:
The Mobile Station shall use ENHANCED MEASUREMENT REPORT messages instead of MEASUREMENT REPORT messages if that is indicated by the parameter REPORT_TYPE and if at least one BSIC is allocated to each BA (list) frequency.
BSIC list received in one or more instances, in ascending order of SI2quater_INDEX, of the SI2quater message. When the BA_IND is changed the MS shall rebuild the combined list (the BSIC list shall also be rebuilt).
If GPRS BSIC Description is provided in the SI2quater message (see sub-clause 126.96.36.199.1.6), it shall be saved and used by a non-GPRS mobile station as initial BSIC information in connected mode.
So my understanding is that the "BSIC list" in SI2quater is actually the field defined as "GPRS BSIC Description", which is used also for non-GPRS purposes.
Here's what's needed in order to support EMR in both osmo-bts and osmo-bsc:
- Set "MEASUREMENT PARAMETERS=>REPORT_TYPE" in SI2quater Rest Octets to 1 (or make it configurable via VTY)
- Make sure we send EMR BSIC list in either SI2quater or SI2n (Hardcoded "0" in osmo_gsm48_rest_octets_si2quater_encode, pass list in osmo-bsc)
- osmo-bts: Support parsing Enhanced Measurement Reporting packet & forarding: add support in rslms_is_meas_rep() and lchan_bs_pwr_ctrl() (and repeated_dl_facch_active_decision() too?), other stuff should be fine, since it's mostly forwarding l3 which is transparent to BTS
- osmo-bsc: Feeding information from Enhanced Measurement Reporting into existing measurement infrastructure: add support in rsl_rx_meas_res (add new function like gsm48_parse_meas_rep()), add support in dispatch_dtap()