SMLC SoCv1 0 (2)

SMLC

Statement of Compliance

Version 1.0

28 August, 2010

© Creativity Software 2010 1

1 About this Document

1.1 Audience

The audience for this document is:

• Client Technical Team• Creativity Software Ltd Technical Team

1.2 Document history

Version Author Description Date

0.1 Deepti Bharti Initial version 23 Sep, 2010

1.0 Deepti Bharti Template change 28 Sep, 2010

1.3 Supporting documents

3GPP TS 48.071 Serving Mobile Location Centre - Base Station System (SMLC-BSS) interface;

Layer 3 specification (Release 10)

3GPP TS 44.018 Mobile radio interface layer 3 specification;

3GPP TS 49.031 Base Station System Application Part LCS Extension (BSSAP-LE) (Release 10)


Contents

1 About this Document ..................................................................................................................... 2

1.1 Audience ............................................................................................................................. 2

1.2 Document history ............................................................................................................... 2

1.3 Supporting documents ........................................................................................................ 2

2 SMLC Description ........................................................................................................................... 3

3 SMLC Capabilities .......................................................................................................................... 4

4 SMLC Messages ............................................................................................................................ 4

4.1 BSSMAP-LE Messages ......................................................................................................... 4

4.2 BSSLAP Messages ................................................................................................................ 5

5 SMLC Operation ............................................................................................................................ 6

5.1 Normal Operation .............................................................................................................. 6

5.2 SMLC Operation without TA Request ................................................................................. 8

5.3 SMLC BSS-Reset ................................................................................................................. 9

5.4 BSSMAP-LE Perform Location Information ....................................................................... 10

5.5 BSSMAP-LE Perform Location Abort ................................................................................. 11

5.6 BSSLAP Reject .................................................................................................................. 12

5.7 BSSLAP Reset ................................................................................................................... 13

5.8 BSSLAP Abort ................................................................................................................... 15

2 SMLC Description

Serving Mobile Location Centre is a GSM network element deployed to calculate the geographic location using Cell ID, TA(Timing Advance) and from RF power levels when available . It communicates with the BSS to receive this information and return a best calculated position in terms of Latitude/Longitude for a particular UE. ‘Requests’ are made to the SMLC from the GMLC which in turn accepts location requests from the LCS Client.


3 SMLC Capabilities

• Creativity’s SMLC supports location requests for “Current Geograph-ic Location” for TA-based positioning.

• Creativity’s BSS based SMLC will be installed to establish Lb inter-face signalling with BSCs in MNO’s network.

• The SMLC and ‘Location Calculation’ specific code shall run on the same server with the SMLC interfaced to a G31 signalling server for access to existing network nodes.

• The SMLC shall serve multiple BSCs for the purpose of obtaining ra-dio interface measurements to assist in locating the target UE.

• Creativity’s SMLC implementation is based on 3GPP TS 09.31 for the Lb interface with BSSMAP-LE PERFORM LOCATION REQUEST and BSSMAP-LE PERFORM LOCATION RESPONSE primarily over SCCP for TA positioning method. Optional parameters are vendor specific and not supported.

4 SMLC Messages

4.1 BSSMAP-LE Messages

BSSMAP-LE messages are transferred between a BSS and SMLC and

comprise the following individual messages:


4.1.1 BSSMAP-LE PERFORM LOCATION REQUEST message

This message is sent from the BSS to the SMLC to request a location estimate for a target MS and contains sufficient information to enable location according to the required QoS using any positioning method supported by the network.

4.1.2 BSSMAP-LE PERFORM LOCATION RESPONSE message

This message is sent from the SMLC to the BSS in response to a BSSMAP-LE Perform Location Request and returns a successful location estimate for a target MS or reports a failure in obtaining the required location.

4.1.3 BSSMAP-LE PERFORM LOCATION ABORT message

This message is sent to the SMLC via the BSS and GMLC by the instigator of a location request to abort the positioning attempt.

4.1.4 BSSMAP-LE CONNECTION ORIENTED INFORMATION message

This message can be sent between the BSS and SMLC in association with an existing signaling connection between an SMLC and another entity to transfer information between the SMLC and other entity belonging to a higher level protocol.

4.1.5 BSSMAP-LE RESET message

This message is sent to indicate a failure in the sending entity and location service transactions that were established or were being established. The message may be sent from an SMLC to a BSS and from a BSS to an SMLC. This message is sent as a connectionless SCCP message.

4.1.6 BSSMAP-LE RESET ACKNOWLEDGE message

This message is sent in response to a Reset message to indicate that references and resources associated with LMU connections and location service transactions towards the entity sending the Reset have been released. The message may be sent from an SMLC to a BSS and from a BSS to an SMLC.

This message is sent as a connectionless SCCP message.

4.1.7 BSSMAP-LE PERFORM LOCATION INFORMATION message

This message is sent from the BSS to the SMLC to notify the SMLC that

the target MS is now located in a new cell.

4.2 BSSLAP Messages


4.2.1 TA Request

The TA Request is a message from the SMLC to the BSS, requesting BSS to return the timing advance (or access delay) of the MS.

4.2.2 TA Response

The TA Response is a message from the BSS to the SMLC. It is a response to TA Request message

4.2.3 Reject

The Reject is a message from the BSS to the SMLC. It is a possible response to TA Request, MS Position Command or U-TDOA Request.

4.2.4 Reset

The Reset is a message from the BSS to the SMLC. It is sent when the

response message contents for a positioning.

4.2.5 Abort

The Abort is a message from the BSS to the SMLC. Upon receiving this signal, the SMLC shall abort ongoing positioning procedure.

4.2.6 TA Layer3

The TA Layer3 is an optional encapsulated message from the BSS to the SMLC that adds the following information in Complete layer 3 Information as described in 3GPP TS 48.008.

5 SMLC Operation

5.1 Normal Operation


Figure-5.1

1. The BSS Initiates a BSSMAP-LE Perform Location Request within a new SCCP Connection attempt and provides Location Type and Serving Cell ID as mandatory parameters. Optionally a BSSLAP APDU containing a TA Layer 3 message may also be provided. In this example, it is assumed the TA Layer 3 message is present and contains BSSLAP Timing Advance, BSSLAP Measurement Report and BSSLAP Measured Cell Identity List parameters. This is a BSS SMLC and only supports 'Current Location' location requests, using TA positioning methods described in 3GPP 03.71, section 8.

2. The SMLC does not require any further measurement data and immediately responds with an SCCP Connection Confirm message to the initiator, and queues the request for calculation.

3. The SMLC closes the connection with a BSSMAP-LE Perform Location Response message, containing either the Location Estimate upon success, or LCS Cause upon failure.

4. The BSS finally acknowledges the release of the connection.


5.2 SMLC Operation without TA Request

Figure-5.2

1. The BSS Initiates a BSSMAP-LE Perform Location Request within a new SCCP Connection attempt and provides Location Type and Serving Cell ID as mandatory parameters, and optionally a BSSLAP APDU containing a TA Layer 3 message. In this example, it is assumed that the TA Layer 3 message is NOT present, or is present but does not contain data to allow for satisfactory precision.

2. The SMLC requests further measurement data via a BSSMAP-LE Connection Oriented Information / BSSLAP TA Request message to the BSS on the same connection.

3. The BSS responds with a BSSMAP-LE Connection Oriented Information / BSSLAPTA Response message. This contains the Cell Identity and Timing Advance as mandatory parameters, and optionally further measurement details. From this the SMLC draws appropriate data for location calculation and queues the request for calculation.


4. The SMLC closes the connection with a BSSMAP-LE Perform Location Response message, containing either the Location Estimate upon success or LCS Cause upon failure.


5.3 SMLC BSS-Reset

Figure-5.3

At any stage during a location procedure the BSS may send a BSSMAP Reset message.

1. Upon receiving a BSSMAP-LE Reset message, the SMLC releases all resources allocated to a Location Procedure.


2. The SMLC closes the SCCP connection by returning a BSSMAP-LE Reset Acknowledge.


5.4 BSSMAP-LE Perform Location Information

Figure-5.4

At any stage during a location procedure the BSS may send a BSSMAP Perform Location Information.

1. Upon receiving a BSSMAP-LE Perform Location Information, the SMLC reads the new Location Information for relevant Serving Cell, Timing Advance and measurement data, and queues the modified request for calculation.




5.5 BSSMAP-LE Perform Location Abort

Figure-5.5

At any stage during a location procedure the BSS may send a BSSMAP Perform Location Abort.

1. Upon receiving a BSSMAP-LE Perform Location Abort from the BSS, the SMLC clears all resources relating to the established Location Procedure.


2. The SMLC closes the connection with a BSSMAP-LE Perform Location Response message, with LCS Cause “Location Request Aborted”.


5.6 BSSLAP Reject

Figure-5.6

The BSSLAP-Reject message may be a response to a TA Request from the SMLC.


1. The initial Perform Location Request is received by the SMLC, but does not contain the parameters required for optimal position calculation.

2. The SMLC requests further location information from the BSS by sending a BSSMAP Connection Oriented Information /BSSLAP TA Request Message.

3. The BSS rejects this by responding with a BSSMAP Connection Oriented Information message / BSSLAP Reject message. The SMLC uses as much information as it has received leading up to this state, and queues the request for calculation.



5.7 BSSLAP Reset


Figure-5.7

Prior to the completion of a location procedure, the BSS may send a BSSLAP-Reset message.

1. The BSS recognises that the previous data sent to the SMLC has now been invalidated (i.e. due to handover) and now sends new position-related information to the SMLC. The SMLC discards the previously allocated position-related information and updates the request with this new data, and queues the request for calculation.




5.8 BSSLAP Abort


Figure-5.8

At any stage during an established location procedure, the BSS may send a BSSLAP-Abort message.

1. The BSS may require the SMLC to abort the operation and sends the BSSLAP-Abort message. Upon receiving this message, the SMLC releases all resources allocated to the relevant location procedure.

2. The SMLC closes the connection with a BSSMAP-LE Perform Location Response message, containing the LCS Cause 'Location Request Aborted'.



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