16 Cell Site Reporting

33.1083G Security3GPPHandover interface for Lawful Interception (LI)Release 17TS

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

16.1 Overview

When a Cell Site Identity is provided in an IRI event, the CSP may provide the specific Cell Site Supplemental Information records from their Cell Site database. This information should be placed in the events location parameter if the IRI message is still available in the MF before its delivery or use a separate Cell Site Report (CSR) capability as described in TS 33.107 [19] Clause 22 Cell Site Supplemental Information Reporting. If the Cell Site Supplemental information for a Cell Site Identity has already been sent for an intercept and it has not changed, the CSP is not required to send the record again.

16.2 LI_CELL_INFO Interface

The LI_CELL_INFO interface, as identified in its configuration in [19] clause 4 figure 1m, is used by the MF to access a CSP cell site database(s) that have additional Cell Site Supplemental Information. The MF will query or the MF will be provided from/to the CSP database any supplemental information for a Cell Site Identity across this LI_CELL_INFO interface and shall place this information into the Location parameter of the IRI event, however, if this IRI event is not available in the MF, the MF shall have the ability to create a CSR to be delivered to the LEMF.

16.3 Cell Site Reporting in IRI event

If an IRI event Record from the network contains a Cell Site Identity (e.g. Cell Global Identifier), the MF should enrich the IRI Record with Cell Site Supplemental Information retrieved from the CSP’s Cell Site Database prior to delivery of the IRI to the LEMF. The parameters as shown in Table 16.1 shall be included within the location parameter. However, if the MF cannot insert this information without undue delay into the IRI event Record, the MF should create and deliver a separate CSR as shown in 16.4 Table 16.2.

Table 16.1: Cell Site Supplemental information Parameters

Parameter	Description	ASN.1 parameter
azimuth	If known, the median of the Cell antenna sector accessed in degrees.	locationOfTheTarget/Location/gsmLocation/ GSMLocation/geoCoordinates/azimuth (for 2G/3G) or ePSlocationOfTheTarget/EPSLocation/gsmLocation/GSMLocation/ geoCoordinates/azimuth (for 4G)
latitude longitude	If known, the geoCoordinates of the cell site (latitude and longitude).	locationOfTheTarget/Location/gsmLocation/ GSMLocation/geoCoordinates/latitude (for 2G/3G) or ePSlocationOfTheTarget/EPSLocation/gsmLocation/GSMLocation/geoCoordinates/ latitude (for 4G) and locationOfTheTarget/Location/gsmLocation/ GSMLocation/geoCoordinates/longitude (for 2G/3G) or ePSlocationOfTheTarget/EPSLocation/gsmLocation/GSMLocation/geoCoordinates/longitude (for 4G)
civicAddress	If known, the civic address of the cell site.	locationOfTheTarget/Location/civicAddress (for 2G/3G) or ePSlocationOfTheTarget/EPSLocation /civicAddress (for 4G)
operatorSpecificInfo	If provided, other Carrier-specific information whose format is not standardized inserted here.	locationOfTheTarget/Location/operatorSpecificInfo (for 2G/3G) or ePSlocationOfTheTarget/EPSLocation/ operatorSpecificInfo (for 4G)

16.4 Cell Site Report

A dedicated Cell Site Report Record shall be created when the MF could not enrich an IRI event message as described in clause 16.3.

If the Cell Site Supplemental information for a Cell Identity has already been sent for an intercept and it has not changed, the CSP is not required to send the record again.

– The type of this IRI report shall use the IRI-Report-record

Table 16.2: Cell Site Report Record

Parameter	MOC	Description/Conditions
Event Type	M	Shall indicate a CSR report.
TimeStamp	M	Shall provide the date and time the event is detected.
Network-Identifier	M	Shall be provided.
LawfulInterceptionIdentifier	M	The Lawful Interception Identifier.
Location	C	Shall provide the reported Cell Supplemental Information for the Cell Identity as define in Table 16.1 when reporting a 2G/3G location The Location parameter shall also include the identity of the cell location (in globalCellID for instance). Either Location or EPSLocation shall be used.
EPSLocation	C	Shall provide the reported Cell Supplemental Information for the Cell Identity as define in Table 16.1 when reporting a 4G location. The EPSLocation parameter shall also include the identity of the cell location (in userLocationInfo for instance).