A.10 Multilateration OTD Request

3GPP44.031Location Services (LCS)Mobile Station (MS) - Serving Mobile Location Centre (SMLC) Radio Resource LCS Protocol (RRLP)Release 17TS

Tools: ARFCN - Frequency Conversion for 5G NR/LTE/UMTS/GSM

A.10.1 General

The Multilateration OTD (MOTD) request is an RRLP component from the network to the MS. This message is sent to MS to start MOTD measurements of neighbour base stations based on the given cell list

Table A.63: Multilateration OTD Request content

Element	Type/Reference	Presence
Target Number of OTD measurements	Target Number of OTD Measurements 10.2.1	M
Required DL Synchronisation Accuracy	Required DL Synchronisation Accuracy 10.2.2	M
Serving Cell Set	Cell Set 10.2.3	O
Neighbouring Cell Set	Cell Sets 10.2.4	O

A.10.2 Elements

A.10.2.1 Target Number of OTD Measurements

This element indicates the number of OTD measurements required to achieve the estimated positioning accuracy. The MS can complete the OTD measurement procedure once the target number of OTD measurements are completed or if no neighbour cells from further neighbour cell sites can be received and send the Multilalteration OTD response message.

A.10.2.2 Required DL Synchronisation Accuracy

This element indicates the downlink synchronisation accuracy the MS should try to achieve with serving cell and neighbour cells. MS shall estimate the DL sync accuracy (i.e MS Sync Accuracy (see 3GPP TS 45.010)) on reception of every additional synchronisation burst reception. MS stops further reception and processing of synchronisation bursts if the estimated downlink sync accuracy is better than the required DL synchronisation accuracy or the maximum number of synchronisation iterations is already reached.

A.10.2.3 Serving Cell Set

This element contains the list of cells which are co-sited with the serving cell. MS shall avoid OTD measurements on the cells from this cell set. Each information element consists of ARFCN and BSIC of the cell as shown in Table A.64.

Table A.64: Cell Set

MOTD Measurements Parameter

ARFCN

BSIC

A.10.2.4 Neighbour Cell Sets

This information element provides up to 8 cell sets where each neighbour cell set consists of information about co-sited cells of (at least) one neighbour cell site. The co-sited cell information is used by MS while measuring the OTD with the neighbour cells. The MS shall measure the OTD only with the strongest cell per neighbour cell set.

Each Cell set information element indicates the ARFCN and BSIC of the cell (refer to Table A.64).