SUPL Functions in SUPL Subsystems

1. SUPL Location Services Functional Group

1.1. SUPL Privacy Function (SPF)

The SPF is the function of ensuring the privacy of a SET User is honored. The following must be considered:

• Adhere to the target SET User privacy setting regardless of SUPL Network Initiated Services or SET Initiated Services
• Adhere to notification and verification settings of the target SET User
• Allow override of the target SET User privacy settings as mandated or allowed by local regulations for positioning for an emergency services call
• Allow for future lawful override regulations that may apply to the target SET User

SUPL may use other enablers to implement parts of the SPF. Alternatively, the SPF may be implemented in the SET.

1.2. SUPL Initiation Function (SIF)

The SIF provides a mechanism for a SUPL Network to initiate a transaction with a SET. The initiation function is of special importance in enabling SUPL Network Initiated Services.
In case of a SUPL Network Initiated Service the SUPL Network initiates the SUPL transaction by using one of the following methods:

• OMA Push
• SMS directly in an MNO environment
• UDP/IP
• SIP Push [SIP PUSH]

Note: OMA Push is considered to be any delivery method that utilizes the Push Access Protocol (PAP), regardless of whether POTAP or SIP Push is used for the final delivery to the SET.
Depending upon SET capabilities, the applicable SIF method is applied by the SUPL Network (determination of SET capabilities is out of scope of SUPL).

A SET SHALL support the SIF using at least one of POTAP, SIP Push and SMS. A SET that is capable of initiating an emergency services call using an IP bearer1 SHALL also support the SIF using UDP/IP or SIP Push.

For GSM/WCDMA/TD-SCDMA deployments, the SIF using OMA Push SHALL be supported by both the SET and the SLP. For CDMA/CDMA2000 deployments, the SIF using MT SMS SHALL be supported by both the SET and the SLP. Support of other transport protocols is optional.

1.3. SUPL Security Function (SSF)

The SSF enables the SUPL Network to authenticate and authorize the SET and enables the SET to authenticate and authorize the SUPL Network. This is important in safely enabling both SUPL Network Initiated Services and SET Initiated Services.

The SSF also provides confidentiality and data integrity. Refer to Section 6 in the SUPL 2.0 ULP TS for details of the SSF implementation.

3. SUPL Roaming Support Function (SRSF)


For positioning not associated with an emergency services call, SUPL roaming occurs when a SET leaves the service area of its H-SLP. For positioning associated with an emergency services call, SUPL roaming occurs when the SET is not within the service area of the E-SLP. The service area of an H-SLP or E-SLP includes the area within which the H-SLP or E-SLP can provide a position estimate for a SET or relevant assistance data to a SET without contacting other SLPs. It should be noted that an H-SLP or E-SLP service area is not necessarily associated with the service area(s) of the underlying wireless network(s).

There are variants of SUPL roaming which are summarized below:

• The H-SLP or E-SLP may request the V-SLP to provide an initial position estimate, e.g., based upon Location ID.
• The H-SLP or E-SLP may request the V-SLP to provide the Lup Positioning Determination and SPC functionality.

The decision of which variant is applied is implementation specific and out of the scope of this specification. For information purposes, the decision will depend upon such factors as:

(i) Roaming agreements between SUPL Providers;
(ii) Location ID;
(iii) Cached information;
(iv) H-SLP/SET or E-SLP/SET negotiation parameters such as positioning method.

1.4. SUPL Charging Function (SCF)

The SCF is responsible for charging activities within the SLP. This includes charging of MLS Application, SUPL Agents and SET Users.

The main task of the SCF is to collect appropriate charging related data and data for accounting between SUPL Providers. Additionally, the SCF may authorize activities in the SLP (e.g., assistance data and location delivery) based on assessment of available charging data. Further details of the SCF are outside the scope of SUPL.

1.5. SUPL Service Management Function (SSMF)

The SSMF is the function of managing locations of SETs. This function stores, extracts, and modifies the location information of a target SET. During the execution of this function, the integration with charging, privacy, security, QoP functions SHALL be considered.

1.6. SUPL SET Provisioning Function (SSPF)

The SSPF is the function that manages the provisioning for the SET. The SET SHALL be provisioned with the address of the Home SLP. The provisioning of the Home SLP address in the SET MAY use OMA enablers to provision the SET.

1.7. SUPL Triggering Function (STF)

The SUPL Triggering Function is the function of communicating periodic and event based triggers between the SLP and the SET and evaluating when those trigger conditions have been fulfilled.

For Network Initiated Triggered Services, the SLP delivers trigger criteria to the SET. For SET Initiated Triggered Services, the SET sends trigger criteria to the SLP. In some circumstances, the SLP may also return additional trigger criteria to the SET during SET Initiated Triggered Services (e.g., an area id list if the SET has requested an event based trigger with a geographic target area).
It is the responsibility of the SET to determine when these trigger criteria have been met.

For periodic triggers, the criteria may include:

• the number of fixes;
• the interval between fixes;
• a start time for the trigger.

For event based triggers, the criteria may include:

• the type of the area event (Entering, Leaving, Inside or Outside) (see 5.3.1.8.2, OMA-AD-SUPL-V2_0 for more details);
• a geographic target area list;
• an area id list;
• repeated reporting information which indicates whether the SET can re-use the trigger and for how many times and
• at what minimum interval (see5.3.1.8.1, OMA-AD-SUPL-V2_0 for more details);
• a start and a stop time.

When an area id list but not a geographic target area list is present in an event based trigger, the area id list is used as the target area for the trigger. When a geographic target area list is present but not an area id list, the geographic target area list is taken as the target area. When both a geographic target area list and an area id list are present in an event based trigger, the geographic target area is taken as the actual target area and the area id list is used to help the SET avoid unnecessary positioning attempts (the exact procedure will vary based on the type of trigger and is explained in more detail in “UserPlane Location Protocol”, Version 2.0, Open Mobile Alliance, OMA-TS-ULP-V2_0 URL: http://www.openmobilealliance.org/).

2. SUPL Positioning Functional Group

2.1. SUPL Assistance Delivery Function (SADF)

The SADF selects, generates and delivers available assistance data that is used for the measurement or the calculation of a SET position. The assistance data delivery may be based on a selected subset of GPS or GANSS reference data retrieved from SRRF function, the capability of SET and network, and the approximate position information of the target SET.

Assistance data may consist of the elements defined in [3GPP RRLP], [3GPP RRC], [3GPP2 C.S0022-A], [3GPP2 C.S0022-0], or [3GPP LPP].

2.2. SUPL Reference Retrieval Function (SRRF)

The SRRF is the function of retrieving GPS or GANSS reference data from a GPS or GANSS reference network. Reference data is needed to generate assistance data. The interface between this function and GPS or GANSS reference network is outside the scope of this document.

2.3. SUPL Position Calculation Function (SPCF)

The SPCF selects the positioning protocol and protocol version, and performs the function of calculating the position of a SET. One or more of the following positioning calculation modes may be supported by a SUPL service.

• A-GPS SET assisted
• A-GPS SET based
• A-GANSS SET assisted
• A-GANSS SET based
• Autonomous GPS or Autonomous GANSS
• Enhanced Cell/Sector
• AFLT
• EOTD
• OTDOA
• Location ID – SHALL be supported
• Perform translation of a location identifier to a geographic location expressed in latitude and longitude. In MNO environments this is often referred to as Cell-ID location.

Note: Applicability of a particular positioning calculation mode is subject to the support in relevant 3GPP and 3GPP2 specifications that SUPL relies on.

Source: http://www.openmobilealliance.org/release/SUPL/V2_0_3-20160524-A/OMA-AD-SUPL-V2_0-20120417-A.pdf