HK1168482B - Method and apparatus for supporting location services with a streamlined location service layer - Google Patents

Description

Method and apparatus for supporting location services with a streamlined location services layer

I. Priority requirements according to 35 U.S.C. § 119

The present patent application claims priority from U.S. provisional application S/n.61/184,706 entitled "Streamlined SUPL Service Layer" filed on 6/5/2009 and U.S. provisional application S/n.61/185,940 entitled "Streamlined SUPL Service Layer" filed on 6/10/2009, both of which are assigned to the assignee of the present application and are expressly incorporated herein by reference.

Background

I. Field of the invention

The present disclosure relates generally to communication, and more specifically to techniques for supporting location services.

II. background

It is often desirable and sometimes necessary to know the location of a terminal, such as a cellular telephone. The terms "position" and "location" are synonymous and are used interchangeably herein. For example, a location services (LCS) client may wish to know the location of a terminal. The terminal may then communicate with a location server to obtain a location estimate for the terminal. The terminal or location server may then return the location estimate to the LCS client.

The message flow (which may also be referred to as a call flow or procedure) may be performed whenever the LCS client wishes to know the location of the terminal. Various messages may be exchanged between the terminal and the location server via one or more network entities with respect to the message flow. These messages may ensure that each entity is provided with relevant information to support the positioning of the terminal. However, these messages increase traffic at various entities.

The LCS client may wish to know the location of the terminal whenever certain conditions are triggered. The location server may assume the task of performing various functions to detect the trigger condition and send a location estimate to the LCS client whenever the triggered condition is detected. However, these functions may complicate the design and operation of the location server, especially if the location server is required to perform these functions for a large number of terminals. Alternatively, the terminal may assume the task of performing various functions to detect the trigger condition and send a location estimate to the LCS client whenever the triggered condition is detected. In this case, it may be desirable for the terminal to be able to communicate with the location server efficiently when and as needed.

SUMMARY

Techniques for supporting location services with a streamlined location services layer are described herein. The streamlined location service layer may allow a terminal to establish and maintain an extended location session with a location server. Subsequently, the application may be able to efficiently obtain location services from the terminal and the location server at any time during the extended location session, since some or all of the signaling and processing overhead may have occurred at the time the extended location session was established and may not need to be repeated. The streamlined location service layer may also allow the terminal to control parameters (e.g., select a positioning method) to use during the extended location session.

In one design, the terminal may receive the location service request from an application, which may be internal or external to the terminal. The terminal may exchange at least one message with the location server to establish an extended location session of a particular duration. Thereafter, the terminal may obtain location services from the location server at any time within the particular duration of the extended location session, e.g., whenever a location request is received from an application. In one design, the terminal may send a first message to the location server, the first message including a request for assistance data or a location estimate. The terminal may then receive a second message from the location server, the second message including the requested assistance data or a location estimate for the terminal.

The terminal may obtain any number of location services at any time during the extended location session. A terminal or application may emulate a more complex location service (e.g., a periodic triggered location service or an area event triggered location service) based on location information received from all times the location service is obtained by the terminal

Various aspects and features of the disclosure are described in greater detail below.

Brief Description of Drawings

Fig. 1 illustrates an exemplary network deployment.

Fig. 2 shows a call flow for a terminal-initiated extended location session.

Fig. 3 illustrates a call flow for a network-initiated extended location session.

Fig. 4 and 5 illustrate two call flows for obtaining location services during an extended location session.

Fig. 6 shows a process performed by a terminal to obtain location services.

Figure 7 illustrates a process performed by a location server to support location services.

Fig. 8 shows a block diagram of a terminal, an access network and a location server.

Detailed Description

The techniques described herein may be used for user plane and control plane positioning solutions/architectures. The user plane location solution is a location solution that sends location service messages via the user plane. The user plane is a mechanism for carrying signaling and data for higher layer applications and employs user plane bearers, which are typically implemented with standard protocols such as User Datagram Protocol (UDP), Transmission Control Protocol (TCP), and Internet Protocol (IP). The control plane location solution is a location solution that sends location service messages via the control plane. The control plane is a mechanism for carrying signaling for higher layer applications and is typically implemented with network-specific protocols, interfaces, and signaling messages. Messages supporting location services are carried as part of the signalling in a control plane positioning solution and as part of the data (from the network point of view) in a user plane positioning solution. However, the content of the message may be the same or similar in both user plane and control plane positioning solutions.

For clarity, certain aspects of these techniques are described below for Secure User Plane Location (SUPL) of the Open Mobile Alliance (OMA). SUPL is applicable to various wireless and wired networks and is described in publicly available literature from OMA. For clarity, SUPL terminology is used in much of the description below.

Fig. 1 illustrates an exemplary network deployment that supports location services. The terminal 110 may have a service subscription with the home network 102 b. However, the terminal 110 may be roaming to the serving network 102a, which may also be referred to as a visited network 102 a. The terminal 110 may then communicate with the serving network 102a to obtain communication services. In general, a terminal 110 may be stationary or mobile and may also be referred to as a Mobile Station (MS), a User Equipment (UE), an Access Terminal (AT), a subscriber station, a station, and so on. The terminal 110 may be a cellular telephone, a Personal Digital Assistant (PDA), a handheld device, a wireless device, a laptop computer, a wireless modem, a cordless telephone, a telemetry device, a tracking device, and the like. In SUPL, the terminal 110 may be referred to as a SUPL Enabled Terminal (SET). The terms "terminal" and "SET" are used interchangeably herein.

Serving network 102a may include an access network 120, a serving core network 128a, an access network SUPL location platform (a-SLP)130a and other network entities not shown in fig. 1 for simplicity. Access network 120 may be a Radio Access Network (RAN) (as shown in fig. 1) or a wireline access network. The RAN may be a Code Division Multiple Access (CDMA)1X network, a Wideband CDMA (WCDMA) network, a Global System for Mobile communications (GSM) network, a Long Term Evolution (LTE) network, a Wireless Local Area Network (WLAN), or the like. The core network 128a may include network entities that may support various communication services for terminals communicating with the serving network 102 a. a-SLP130a may support location services for terminals in communication with serving network 102a (e.g., including terminals roaming to serving network 102 a) and may or may not require that these terminals have any service subscription or any prior relationship with a-SLP130 a. The core network 128a may also include a visited SLP (V-SLP) that may support location services for terminals roaming to the serving network 102 a.

Home network 102b may include a home core network 128b, a home SUPL location platform (H-SLP)130b, and other network entities not shown in fig. 1 for simplicity. The core network 128b may include network entities that may support various communication services for terminals communicating with the home network 102b or belonging to the home network 102 b. H-SLP 130b may support location services for terminals with service subscriptions with home network 102 b.

a-SLP130a and H-SLP 130b may support location services for terminals/SETs. Location services may include any location-based or location-related services. Location services may include positioning, which is a process for determining a geographic or civil location estimate for a target SET. The target SET is a SET seeking its location information. The position estimate may also be referred to as a position estimate, a position fix, etc. The positioning may provide: (i) latitude, longitude, and possibly altitude coordinates and uncertainty for the geographic location estimate, (ii) street address for the civil location estimate, and/or (iii) speed and/or other information.

The SLP may include a SUPL Location Center (SLC) and a SUPL Positioning Center (SPC). The SLC may support location services, coordinate the operation of SUPL, and interact with the SET over user plane bearers. SLC may perform functions related to privacy, initiation, security, roaming support, billing/accounting, service management, location calculation, etc. The SPC may support positioning of the SET and delivery of assistance data to the SET, and may also be responsible for messages and procedures used for location calculations. The SPC may perform functions related to security, assistance data delivery, reference retrieval, location calculation, and the like.

The SLP may support a proxy mode and/or a non-proxy mode in SUPL. In proxy mode, the SET may communicate with the SLC in the SLP for location services, and the SLC will act as a proxy between the SET and the SPC in the same SLP (for non-roaming) or a separate V-SLP (for roaming). In the non-proxy mode, the SET may communicate directly with the SPC for location after some initial communication with the SLC. In one proxy mode design, the use of V-SLP may be coordinated by H-SLP 130b and may not be visible to SET110 which may only interact with H-SLP 130 b. In one non-proxy mode design, SET110 may interact directly with the V-SLP (e.g., with the SPC in the V-SLP) as directed by H-SLP 130 b.

The SUPL agent 140 may be an LCS client and may communicate with the H-SLP 130b (e.g., directly or via one or more networks) to obtain location information for the target SET. The location information may include a location estimate and/or any information related to location or velocity. The SET may also have a SUPL agent residing on the SET.

terminal/SET 110 may receive and measure signals from satellites, such as satellite 150, to obtain pseudorange measurements for the satellites. These satellites may be part of the united states Global Positioning System (GPS), the european Galileo system, the russian GLONASS system, or some other Satellite Positioning System (SPS). The pseudorange measurements to the satellites and the known locations of the satellites may be used to derive a location estimate for terminal 110. Terminal 110 may also receive and measure signals from base stations within access network 120 and/or other networks in the same geographic area. Terminal 110 may obtain identity information, timing measurements, and/or signal strength measurements for these base stations. The identity information, timing measurements, and/or signal strength measurements for these base stations, as well as the known locations, may be used to derive a location estimate for terminal 110. In general, a position estimate may be derived based on identity information and measurements with respect to satellites, base stations, pseudolites, and/or other transmitters.

The terminal/SET 110 may support one or more positioning methods. The positioning method may support positioning of a target terminal/SET based on measurements of one or more transmitters. For example, the terminal/SET 110 may support autonomous GPS, assisted GPS (a-GPS), advanced forward link trilateration (a-FLT), enhanced observed time difference of arrival (E-OTD), observed time difference of arrival (OTDOA), enhanced cell Identity (ID), cell ID, some other positioning method, or a combination thereof. Autonomous GPS and assisted GPS are positioning methods based on measurements on satellites, and the term "GPS" may refer generically to any GNSS. AFLT, E-OTD, and OTDOA are positioning methods based on timing measurements of base stations in a wireless network.

The terminal/SET 110 may also support one or more positioning protocols. The positioning protocol may define: (i) procedures that may be performed by the target terminal/SET and the location server, and (ii) communications or signaling between the target terminal/SET and the location server. For example, the terminal/SET 110 may support Radio Resource LCS Protocol (RRLP), Radio Resource Control (RRC), LTE Positioning Protocol (LPP), c.s0022 (also known as IS-801), some other positioning protocol, or a combination thereof. RRLP, RRC and LPP are defined by an organization named "third generation partnership project" (3 GPP). IS-801 IS defined by an organization entitled "third Generation partnership project 2" (3GPP 2).

SUPL version 2.0(SUPL 2.0) supports a set of predefined location services such as immediate location service, periodic triggered location service, area event triggered location service, and the like. For immediate location services, the location of the target SET can be determined and provided to the SUPL agent immediately upon request. For periodic triggered location services, the location of the target SET can be periodically determined and provided to the SUPL agent. For area event triggered location services, the location of a target SET may be periodically determined and provided to a SUPL agent when a trigger condition occurs, e.g., whenever the target SET is within a target area or enters or leaves the target area. Each predefined location service in SUPL 2.0 may be invoked by a SUPL agent with a single command. This may simplify the operation of the SUPL agent for more complex location services such as periodic triggered location services and area event triggered location services. The complexity is moved to the SLP and target SET that will track the state information for each invoked location service.

An application may emulate a complex location service (e.g., periodically trigger the location service) by tracking state information and invoking an immediate location service whenever needed. Emulation can reduce the complexity of the SLP and the portion of the target SET that supports SUPL. However, emulation may be inefficient, as more signaling overhead may be incurred for each invocation of the immediate location service.

In an aspect, a streamlined SUPL service layer can be used to provide applications with more efficient access to the SUPL positioning layer. The SUPL location layer may include protocol entities and functions capable of supporting location of a SET. The SUPL service layer may support location services and may communicate with the SUPL positioning layer whenever positioning is required. In one design, the streamlined SUPL service layer may allow a SET to establish and maintain an extended location session with a SLP. An application (e.g., running on the SET) can invoke the SUPL service layer or SUPL positioning layer at any time during the extended location session and can obtain a location estimate as needed and needed during the extended location session. The streamlined SUPL service layer may also allow the SET to configure parameters (e.g., select a positioning method, or a positioning protocol, or quality of positioning (QoP), etc.) for use during the extended location session (e.g., by accounting for the capabilities of the SET and SLP).

Fig. 2 shows a design of a call flow 200 for a SET-initiated extended location session through a streamlined SUPL service layer. An application 112 running on the SET110 may desire location information (e.g., a location estimate) about the SET110 and may send a location service request to a SUPL service layer in the SET110 (step a). For simplicity, the SUPL service layer and SUPL positioning layer in the SET110 will be referred to as the SET110 in the following description unless distinguished from other parts of the SET 110. SET110 may perform a data connection establishment procedure, attach itself to the packet data network if necessary, and establish a secure IP connection to SLP130 (step B). SLP130 may be a-SLP130a in serving network 102a, or H-SLP 130b in home network 102b, or some other SLP.

SET110 may then send a SUPL start message to establish an extended location session with SLP130 (step C). This message may include a session id to identify the extended location session, a location id (lid) to identify the current serving cell of the SET110, capabilities of the SET110 (SET capabilities), a request duration (duration) of the extended location session, and so on. The SET capabilities may include positioning capabilities and/or service capabilities of the SET 110. The positioning capabilities may include positioning methods and positioning protocols supported by the SET 110. The service capabilities may include location services, reporting capabilities, and/or other capabilities supported by SET 110. For extended location sessions, SET capabilities may be limited to options applicable to the streamlined SUPL service layer. The request duration may be selected by the SET110 and may be an expected duration that the SET110 may desire or need location services. The request duration may be selected with or without input from the application 112.

SLP130 may receive a SUPL start message from SET110 and may identify that this message is for an extended location session (rather than a normal location session) based on the duration of the request in the message and/or some other information. SLP130 may extract and store SET capabilities for future use. SLP130 may authenticate and authorize SET110 for the extended location session and may obtain routing information for SET110 (step D). SLP130 may then send a SUPL response message to SET110 (step E). This message may include the session id included in the SUPL start message, the selected positioning method (posmethod), the capabilities of SLP130 (SLP capabilities), the granted duration (duration) of the extended location session, and so on. SLP capabilities may include location capabilities (e.g., supported location methods and protocols) and/or service capabilities of SLP 130. For extended location sessions, SLP capabilities may be limited to options applicable to the streamlined SUPL service layer. The grant duration may be a maximum lifetime of the extended location session and may be equal to, shorter than, or longer than the request duration. The extended location session may terminate upon expiration of the grant duration. The extended location session may also terminate (i) earlier than the grant duration by the SET110 or SLP130 sending a SUPL end message or (ii) extend beyond the grant duration by the SET110 sending another SUPL start message to the SLP 130. SET110 may return an acknowledgement (Ack) to application 112 to indicate the availability of location services (step F).

As shown in fig. 2, an extended location session may be established by simply exchanging two SUPL messages between SET110 and SLP 130. The first SUPL message from the SET110 may include information (e.g., a request duration) for conveying a request to establish an extended location session. The first SUPL message may also include one or more parameters (e.g., related to SET capabilities) that may be used to extend the location session. A second SUPL message from SLP130 may include information (e.g., a grant duration) confirming establishment of the extended location session. The second SUPL message may also include one or more parameters (e.g., related to SLP capabilities) that may be used to extend the location session. Additional SUPL messages may also be exchanged to negotiate certain parameters (e.g., regarding duration, positioning method, etc.) and/or configure additional parameters.

As shown in fig. 2, an extended location session may be established by the SET110 in response to a location service request from the application 112. An extended location session may also be established by the SET110 prior to receiving a location service request from any application such that the extended location session is available if and when location service is requested by any application. In any case, once the extended location session is established, application 112 may obtain location services at any time during the extended location session. The application 112 may send a location request (steps G, J and M) whenever location information (e.g., a location estimate) is desired about the SET 110. SET110 and SLP130 may then exchange messages for the location session to obtain the requested location information (steps H, K and N). Alternatively, if SET 130 has obtained the necessary information (e.g., assistance data) from a previous interaction with SLP130, SET110 may provide the requested location information without interacting with SLP 130. For example, the SET110 and the SLP130 may perform step H and step K may be omitted if assistance data is provided by the SLP130 to the SET110 in step H and is sufficient to enable the SET110 to obtain the location information (e.g., location estimate) requested by the application 112 in step J. The SET110 may return a location response with the requested location information to the application 112 (steps I, L and O). Each location session may include little signaling and processing overhead due to the secure data connection establishment in step B, the pre-configuration of the extended location session in steps C and E, and in some cases assistance data derived from a previous location session, such as for example when the assistance data required for step K is obtained from step H.

The extended location session may terminate when its duration expires. The SET110 may also send a SUPL end message to terminate the extended location session early, for example, due to receipt of a location service termination indication from the application 112 (step P). SLP130 may also send a SUPL end message to terminate the extended location session (not shown in figure 2).

Fig. 3 shows a design of a call flow 300 for a network-initiated extended location session with a streamlined SUPL service layer. Applications 142 internal to the SUPL agent 140 and external to the SET110 may desire location information (e.g., a location estimate) about the SET 110. The application 142 may send a location service request to the application 112 on the SET110 (step a). The application 112 may receive the location service request and may send a location service initiation to the SET110 (step B). Steps C, D, E and F may then be performed as described above for steps B, C, D and E in fig. 2, respectively, to establish an extended location session for the SET110 with the SLP 130. SET110 may send an acknowledgement to application 112 (step G) and application 112 may return a service acknowledgement to application 142 (step H).

Once the extended location session has been established, applications 112 and 142 may obtain location services at any time during the extended location session. The application 112 may send a location request (steps I, M and Q) whenever location information (e.g., a location estimate) is desired about the SET 110. SET110 and SLP130 may then exchange messages for the location session to obtain the requested location information (steps J, N and R). The SET110 may then provide the requested location information to the application 112 (steps K, O and S). Application 112 may then send a location report containing the requested location information to application 142 (steps L, P and T). Each location session may include little signaling and processing overhead due to the secure data connection establishment in step C, the pre-configuration of the extended location session in steps D and F, and in some cases assistance data derived from a previous location session, such as for example when the assistance data required for step N is obtained from step J.

In another exemplary design in fig. 3, application 112 may perform additional services for application 142 based on location information obtained from SET 110. For example, the application 112 may verify whether the SET110 is within a specified geographic area or has just entered or just left the area. The application 112 may then provide additional information to the application 142 (e.g., indicating whether the SET110 is within or has just entered or left the specified geographic area) in steps L, P and T. Alternatively, the application 112 may only perform step L or step P or step T if certain trigger conditions are met (such as, for example, the SET110 just entering or just leaving a specified geographic area).

The extended location session may terminate when its duration expires. The SET110 may also send a SUPL end message to terminate the extended location session early, e.g., due to a location service termination indication from the application 112 or 142 (step U). SLP130 may also send a SUPL end message to terminate the extended location session (not shown in figure 3).

Fig. 4 shows a design of a call flow 400 for extending a location session within a location session. Call flow 400 may be used for each of the location sessions shown in fig. 2 and 3. The SET110 may send a SUPL POS (SUPL location) message to the SLP130 to initiate a location session (step a), e.g., whenever an application 112 on the SET110 wishes to obtain location services. This SUPL POS message may include a session id identifying an extended location session, one or more positioning messages for a selected positioning protocol, a QoP defining the required accuracy of the location estimate, an indication of whether speed is required, and/or other information. The selected positioning protocol may be either LPP or IS-801, both LPP and IS-801 supporting SET-initiated positioning. The positioning message(s) may include related information such as a request for assistance data, measurements for positioning, serving cell ID, other cell IDs, and the like.

The SLP130 may receive the SUPL POS message from the SET110 and may send another SUPL POS message to the SET110 (step B). The returned SUPL POS message may include a session id, one or more positioning messages for the selected positioning protocol, and/or other information. The positioning message(s) may include pertinent information such as assistance data (if requested), a position estimate for the SET110, and the like. The position estimate may be sent in a field of a positioning message or in a field of a SUPL POS message.

SET110 and SLP130 may exchange additional SUPL POS messages (steps C and D). Each SUPL POS message may include a session-id for an extended location session, one or more positioning messages carrying any suitable information, and/or other information. The selected positioning protocol may support one or more positioning methods for one or more access types. Any number of SUPL POS messages may be exchanged between SET110 and SLP130 to request and provide information for one or more selected positioning methods. These SUPL POS messages may be used (i) as container messages for carrying location messages for a selected location protocol, (ii) to carry information (e.g., QoP) regarding the type of location information requested by the SET110, and (iii) to associate the location session with an extended location session.

In one design, SET110 may send a first SUPL POS message for the location session and SLP130 may send the last SUPL POS message. These SUPL POS messages may be sent in pairs, with one SUPL POS message from SET110 followed by another SUPL POS message from SLP130, as shown in figure 4. Multiple SUPL POS messages may also be sent by the SET110 or SLP130 before the return SUPL POS message from the SLP130 or SET110, respectively.

Fig. 5 shows a design of a call flow 500 for extending a location session within a location session. Call flow 500 may also be used for each of the location sessions shown in fig. 2 and 3. The SET110 may send a SUPL POS INIT (SUPL location initiation) message to the SLP130 to initiate a location session (step a), e.g., whenever an application 112 on the SET110 wishes to obtain location services. This SUPLPOS INIT message may include a session-ID identifying the extended location session, SET capabilities, a selected positioning method (posmethod) for the location session, cell information (e.g., serving cell ID and/or other cell IDs), QoP, one or more positioning messages for a selected positioning protocol and carrying any suitable information, and so on.

SET110 and SLP130 may then exchange SUPL POS messages for the location session (step B). Each SUPL POS message may include a session-id for an extended location session, one or more positioning messages for a selected positioning protocol, and/or other information. The selected positioning protocol may be RRLP, RRC, LPP, IS-801, and so on. RRLP and RRC support network-initiated positioning, while LPP and IS-801 support both network-initiated and SET-initiated positioning. Any number of SUPL POS messages may be exchanged between SET110 and SLP130 to request and provide information for one or more positioning methods. Once the exchange of SUPL POS messages is complete, SLP130 may send a SUPL report message containing the session-id and possibly also a position estimate and/or velocity estimate (position) for SET110 (step C). The SUPL report message may be used to indicate the end of the location session and return any position estimates and/or velocity estimates calculated by SLP130 for SET-assisted positioning.

Fig. 4 and 5 illustrate two exemplary call flows for extending a location session within a location session. In general, SET110 may send any suitable SUPL message to initiate a location session with SLP 130. Different SUPL messages may be used for different positioning protocols. For a location session, SET110 and SLP130 may exchange any number of SUPL POS messages that may be used as containers for positioning messages and for associating the location session with an extended location session.

As shown in fig. 4 and 5, little signaling and processing overhead may be incurred for each location session within the extended location session. In fig. 4, SET110 and SLP130 may exchange SUPLPOS messages immediately for positioning without first establishing a secure data connection or sending any overhead SUPL messages. In fig. 5, the SET110 may send a SUPL POS INIT message to initiate a location session. The call flows in fig. 4 and 5 may avoid other overhead SUPL messages that are typically used to initiate a location session, such as SUPL start and SUPL INIT (SUPL INIT) messages.

A SUPL start and SUPL response message pair may be exchanged between SET110 and SLP130 to establish an extended location session as shown in figures 2 and 3. These SUPL messages may be used to configure one or more parameters of the extended location session (e.g., parameters regarding a selected positioning method, a selected positioning protocol, QoP, etc.). The configured parameter(s) may be stored for an extended location session and may be used throughout the extended location session, which may reduce signaling overhead. Each location session within the extended location session may utilize the configured parameter(s).

The techniques described herein may allow the SET110 to have a secure extended location session to allow one or more applications to invoke the SUPL positioning layer at any time to obtain location services. This may improve efficiency, reduce signaling traffic, improve performance, and provide other advantages. The techniques may also allow the SET110 and/or the application 112 to more control parameters used by the location service, for example, to select a positioning method. These techniques may also be used for proxy mode and non-proxy mode in SUPL.

The techniques described herein may allow for the complexity of location services to move from the SET110 and SLP130 to applications (e.g., application 112 running on SET 110). SUPL entities such as SET110 and SLP130 may support a smaller SET of simple location services. These applications may implement complex location services by invoking these simple location services and taking over service control from the SUPL entity. For example, an application may determine when to invoke location services during an extended location session to obtain a location estimate for a target SET, evaluate a trigger condition based on the location estimate, and report the location estimate to an LCS client if needed (e.g., when the trigger condition is satisfied). Moving complexity and session control to applications may allow more location services to be developed for these applications and may also reduce the development time for new location services. For example, an application may be able to emulate complex location services such as periodic triggered location services and area event triggered location services based on simple location services supported by a streamlined SUPL service layer.

In another design, complex location services (e.g., with respect to periodic location, triggered location, etc.) may be supported by a SUPL service layer and/or a SUPL positioning layer in the SET110 on behalf of the internal applications 112 or external applications 142 in the SET 110. The SUPL service layer and SUPL positioning layer in SET110 may support the methods in fig. 2 or 3 to establish an extended location session with SLP130 and obtain location information at periodic intervals during the extended location session (e.g., by invoking steps H, K and N in fig. 2 or steps J, N and R in fig. 3). However, the application 112 may not request location information from the SUPL service layer or the SUPL positioning layer at intervals (e.g., in steps G, J and M in fig. 2 or in steps I, M and Q in fig. 3) and the SUPL service layer and the SUPL positioning layer may not provide location information to the application 112 at intervals (e.g., in steps I, L and O in fig. 2 or in steps K, O and S in fig. 3). Instead, the application 112 may indicate to the SUPL service layer only once (e.g., in step a in fig. 2 or step B in fig. 3) the required complex location service (such as determining when the SET110 has just entered, just left, or is still staying in some specified geographic area). The SUPL service layer and/or SUPL positioning layer may then determine when to obtain location information to support the requested complex location service. When a particular trigger condition is satisfied, the SUPL service layer or SUPL positioning layer may send an indication of the trigger condition (such as, for example, the SET110 entering or leaving a specified geographic area) along with associated location information to the application 112. If application 112 is acting on behalf of application 142, application 112 may forward the location information to application 142. In this design, the service complexity may be hidden from SLP130 and from applications 112 and 142 and may only affect the SUPL layer in SET 110. Additionally, additional complex location services supported by the SUPL layer in the SET110 may or may not be defined as part of SUPL. Accordingly, these additional complex location services may be provided as proprietary non-standardized location services or standardized location services in the SET110 to internal applications (e.g., application 112) or external applications (e.g., application 142) in the SET 110.

The SET110 typically communicates with the H-SLP 130b in the home network 102b for SUPL location sessions. The SET110 may be preconfigured with an address of the H-SLP 130b and may be able to contact the H-SLP 130b using the preconfigured H-SLP address. If the SET110 is roaming, the SET110 may exchange SUPL messages with the H-SLP 130b via various network entities in the serving network 102a and the home network 102 b.

In another aspect, SET110 may communicate with a-SLP130a in serving network 102a (rather than with H-SLP 130b in home network 102 b) for extended location sessions. This may reduce signaling traffic and may also reduce the delay in obtaining location services during the extended location session when the SET110 is roaming. This may also assist a SET that does not have an H-SLP or assist a SET when an a-SLP provides some services that an H-SLP does not provide (e.g., more accurate and reliable location support, or support for access networks that are not supported by an H-SLP).

SET110 may discover a-SLP130a in serving network 102a in various ways. In one design, SET110 may use Dynamic Host Configuration Protocol (DHCP) to obtain the address for a-SLP130 a. The SET110 may broadcast a request for configuration information for a-SLPs for access networks currently serving the SET 110. The DHCP server may receive the request from the SET110 and may respond with configuration information (e.g., address) for the a-SLP130a from a configuration database maintained by the DHCP server. In another design, SET110 may use the Domain Name System (DNS) to obtain the address for a-SLP130 a. SET110 may send a DNS query with an a-SLP domain name (e.g., aslp. network abc. com) derived from the domain name of the access network (e.g., network abc. com) currently serving SET 110. The DNS server may receive the DNS query from the SET110 and respond with an address associated with the domain name. In yet another design, a-SLP130a may be assigned a fixed and well-known address. SET110 may know the fixed address of a-SLP130a and may be able to directly access a-SLP130 a. In yet another design, the access network may provide the address of the associated a-SLP to SET110 when SET110 first attaches to the access network or when SET110 sends a request to the access network for the address of the associated a-SLP.

In one design, a-SLP130a or H-SLP 130b may be selected to serve SET110 based on such things as service and positioning capabilities (of a-SLP130a or H-SLP 130b), billing charges, speed and ease of access (e.g., signaling bandwidth and delay), etc. As an example, a 3GPP H-SLP may not be able to support positioning of a SET accessing a 3GPP2 network (or vice versa), which may necessitate the use of a-SLPs. a-SLP130a may support both a streamlined SUPL service layer and a normal/full SUPL service layer (e.g., as described in SUPL 2.0). Security including mutual authentication and encryption may be used for communication between the SET110 and the a-SLP130 a. Security for the streamlined SUPL service layer may be achieved (i) in a similar manner as security for communication between SET110 and H-SLP 130b for a full SUPL service layer or (ii) using different procedures, e.g., different authentication methods.

In yet another aspect, all or a portion of SUPL may be implemented using extensible markup language (XML). For example, the portion of SUPL associated with the streamlined SUPL service layer can be implemented in XML. In one design, asn.1 (abstract syntax notation 1) may be reserved as the scheme for SUPL, and International Telecommunications Union (ITU) x.693 may be used to encode this in XML (e.g., with XER coding). In another design, a new Document Type Definition (DTD) scheme or XML Scheme Definition (XSD) scheme may be defined from the SUPL asn.1 definition, but may be limited to SUPL messages and parameters applicable to the streamlined SUPL service layer. In both designs, only a subset of SUPL may be affected by implementations in XML, and the impact may be limited to the front-end encoder and parser. Negotiation between asn.1 and XML can be avoided by defining asn.1 or XML by agreement on any a-SLP and can be configured for H-SLP on the SET's Subscriber Identity Module (SIM) card.

Other location protocols such as RRLP, RRC, LPP, and IS-801 may also be converted from asn.1 (or some other format) to XML. The conversion may be syntactic rather than semantic (i.e., format change rather than content change). The XML version of a given positioning protocol (which may be referred to as the XML positioning protocol) may support the same assistance data and measurement types as the asn.1 version of the positioning protocol. New positioning methods and changes to existing positioning methods may be added to the resulting XML positioning protocol. For example, the XML positioning protocol may be extended to support positioning for non-3 GPP and non-3 GPP2 access types such as Wi-Fi, fixed bandwidth, WiMAX, and the like.

Fig. 6 shows a design of a process 600 performed by a terminal/SET to obtain location services. The terminal may receive the location service request from an application, which may be internal to the terminal (e.g., as shown in fig. 2) or external to the terminal (e.g., as shown in fig. 3) (block 612). The terminal may exchange at least one message with the location server to establish an extended location session of a particular duration (block 614). The terminal may establish the extended location session (i) in response to a location service request from an application or (ii) before receiving any location service request.

The terminal may receive a location request from the application (block 616). As part of the extended location session, the terminal may obtain location services from the location server at any time within the particular duration of the extended location session, e.g., in response to receiving the location request (block 618). The terminal may send a location response including the location information to the application (block 620).

In one design, the terminal and the location server may exchange SUPL messages for the extended location session. The terminal may determine a session ID for the extended location session. The terminal may use the session ID to identify messages exchanged with the location server to obtain location services during the extended location session.

In one design of block 614, the terminal may exchange the at least one message with a location server to further configure at least one parameter of the extended location session. The at least one configured parameter may comprise a selected location method, or a selected location protocol, or a QoP, or some other parameter, or a combination thereof. Thereafter, the terminal may obtain a location service from the location server based on the at least one configured parameter.

In one design of block 614, the terminal may send a first message (e.g., a SUPL start message) to the location server to initiate establishment of the extended location session. The terminal may receive a second message (e.g., a SUPL response message) sent by the location server to confirm establishment of the extended location session. In one design, the first message may include a request duration for an extended location session and the second message may include a grant duration for the extended location session. The particular duration of the extended location session may be equal to the granted duration or may be otherwise determined. In one design, the first message may include location capabilities of the terminal and the second message may include location capabilities of the location server. The first and second messages may also include other information.

In one design of block 618, the terminal may send a third message (e.g., a SUPL POS message or a SUPL POS INIT message) to the location server to obtain location services. The terminal may receive a fourth message (e.g., a SUPL POS message or a SUPL report message) including location information from the location server. In one design, the third message may include a request for assistance data and the location information in the fourth message may include assistance data for the terminal. In another design, the third message may include measurements and the location information may include a location estimate for the terminal. In one design, the third message may include a positioning method selected by the terminal, or at least one positioning message for the selected positioning method, or some other information, or a combination thereof.

In one design, the terminal may obtain location services multiple times during the extended location session. The terminal may receive location information (e.g., a location estimate for the terminal) each time a location service is obtained. The terminal (or an application at the terminal) may use the location information to emulate a periodically triggered location service, or an area event triggered location service, or some other location service that is more complex than an immediate location service. In general, a terminal may obtain any number of location services at any time during an extended location session. The terminal may emulate any location service based on the location information received from all times the location service is obtained by the terminal.

The extended location session may terminate upon expiration of the particular duration. In one design, the location server may send a SUPL end message to the terminal to explicitly terminate the extended session (or vice versa) when the duration has expired. In another design, the terminal may exchange messages with the location server to terminate the extended location session before the expiration of the particular duration, e.g., as shown in fig. 2 and 3. In yet another design, the terminal may send a message to the location server requesting extension of the extended location session beyond the particular duration.

In one design, the terminal may communicate with a home network and the location server may be an H-SLP (or some other location server) residing in the home network. In another design, the terminal may be roaming away from the home network and may communicate with the serving network. In this case, the location server may be an A-SLP in the serving network or an H-SLP in the home network. The terminal may discover the a-SLP using DHCP or DNS, or when attaching to the serving network, or using some other mechanism.

Fig. 7 shows a design of a process 700 performed by a location server (e.g., an SLP) to support location services. The location server may exchange at least one message with the terminal to establish an extended location session of a particular duration (block 712). As part of the extended location session, the location server may provide location services to the terminal when requested by the terminal at any time within the particular duration of the extended location session (block 714).

In one design of block 712, the location server may receive a first message sent by the terminal to initiate establishment of an extended location session. The location server may send a second message to the terminal to confirm establishment of the extended location session. In one design, the first message may include a request duration for an extended location session, a capability of the terminal, and/or the like. The second message may include a granted duration for the extended location session, capabilities of the location server, and so on. The message exchange may also configure at least one parameter of the extended location session, e.g., a selected location method, a selected location protocol, QoP, etc. The location server may provide location services to the terminal based on the at least one configured parameter.

In one design of block 714, the location server may receive a third message sent by the terminal to obtain location services. The location server may send a fourth message including the location information to the terminal. The third message may include a request for assistance data, measurements, selected positioning methods, etc. The fourth message may include assistance data for the terminal, a location estimate for the terminal, and/or some other location information. The location server may provide location services to the terminal multiple times during an extended location session to enable the terminal to repeatedly obtain location information or emulate a periodically triggered location service, or an area event triggered location service, or some other sophisticated location service.

The extended location session may terminate upon expiration of the particular duration. In one design, the location server may send a SUPL end message to the terminal to explicitly terminate the extension session (or vice versa) when the duration has expired. In another design, the location server may exchange a message with the terminal to terminate the extended location session before the expiration of the particular duration, e.g., as shown in fig. 2 or 3. In yet another design, the location server may receive a message sent by the terminal requesting extension of the extended location session beyond a particular duration. The location server may (i) grant the request and extend the extended location session or (ii) deny the request and terminate the extended location session upon expiration of the particular duration.

Fig. 8 shows a block diagram of a design of terminal/SET 110, access network 120, and location server/SLP 130. For simplicity, fig. 8 illustrates only one controller/processor 810, one memory 812, and one transmitter/receiver (TMTR/RCVR)814 for terminal 110, only one controller/processor 820, one memory 822, one transmitter/receiver 824, and one communication (Comm) unit 826 for access network 120, and only one controller/processor 830, one memory 832, and one communication unit 834 for SLP 130. In general, each entity may include any number of processing units (e.g., processors, controllers, etc.), memories, transmitters/receivers, communication units, etc. Terminal 110 may support communication with one or more wireless networks and/or wired networks. The terminal 110 may also receive and process signals from one or more SPS, such as GPS, Galileo, GLONASS, etc.

On the downlink, access network 120 may transmit traffic data, signaling, and pilot to terminals within its coverage area. These various types of information may be processed by processor 820, conditioned by transmitter 824, and transmitted on the downlink. At terminal 110, the downlink signals from access network 120 may be received and conditioned by a receiver 814 and further processed by a processor 810 to obtain various types of information. Processor 810 may perform process 600 in fig. 6 and/or other processes for the techniques described herein. The processor 810 may also perform the processing of fig. 2 through 5 with respect to the SET 110. Memories 812 and 822 may store program codes and data for terminal 110 and access network 120, respectively. On the uplink, terminal 110 may transmit traffic data, signaling, and pilot to access network 120. These various types of information may be processed by processor 810, conditioned by transmitter 814, and transmitted on the uplink. At access network 120, the uplink signals from terminal 110 and other terminals may be received and conditioned by a receiver 824 and further processed by a processor 820 to obtain various types of information from the terminals. Access network 120 may communicate with SLP130 directly or indirectly via communication unit 826.

Within SLP130, a processor 830 may perform processing to support location services for the terminal. For example, processor 830 may perform process 700 in fig. 7 and/or other processes for the techniques described herein. Processor 830 may also perform the processing of figures 2 through 5 for SLP 130. The processor 830 may also provide assistance data to the terminal 110, calculate a position estimate for the terminal 110, provide position information to the SUPL agent 140, and so forth. Memory 832 may store program codes and data for SLP 130. Communication unit 834 may allow SLP130 to communicate with access network 120, terminal 110, and/or other network entities (not shown in fig. 8). SLP130 and terminal 110 may exchange messages (e.g., SUPL messages) and these messages may be transmitted via access network 120.

Those of skill in the art would understand that information and signals may be represented using any of a variety of different technologies and techniques. For example, data, instructions, commands, information, signals, bits, symbols, and chips that may be referenced throughout the above description may be represented by voltages, currents, electromagnetic waves, magnetic fields or particles, optical fields or particles, or any combination thereof.

Those of skill would further appreciate that the various illustrative logical blocks, modules, circuits, and algorithm steps described in connection with the disclosure herein may be implemented as hardware, computer software/firmware, or combinations of both. To clearly illustrate this interchangeability of hardware and software/firmware, various illustrative components, blocks, modules, circuits, and steps have been described above generally in terms of their functionality. Whether such functionality is implemented as hardware or firmware/software depends upon the particular application and design constraints imposed on the overall system. Skilled artisans may implement the described functionality in varying ways for each particular application, but such implementation decisions should not be interpreted as causing a departure from the scope of the present disclosure.

The location determination techniques described herein may be implemented in conjunction with various wireless communication networks, such as a Wireless Wide Area Network (WWAN), a Wireless Local Area Network (WLAN), a Wireless Personal Area Network (WPAN), and so on. The terms "network" and "system" are often used interchangeably. The WWAN may be a Code Division Multiple Access (CDMA) network, a Time Division Multiple Access (TDMA) network, a Frequency Division Multiple Access (FDMA) network, an Orthogonal Frequency Division Multiple Access (OFDMA) network, a single carrier frequency division multiple access (SC-FDMA) network, a Long Term Evolution (LTE) network, a WiMAX (IEEE 802.16) network, or the like. A CDMA network may implement one or more Radio Access Technologies (RATs), such as CDMA2000, wideband CDMA (W-CDMA), and so on. Cdma2000 covers IS-95, IS-2000 and IS-856 standards. A TDMA network may implement Global System for Mobile communications (GSM), digital advanced Mobile Phone System (D-AMPS), or some other RAT. GSM and W-CDMA are described in documents from a consortium named "third generation partnership project" (3 GPP). Cdma2000 is described in a document from a consortium named "third generation partnership project 2" (3GPP 2). The 3GPP and 3GPP2 documents are publicly available. The WLAN may be an IEEE 802.11x network, and the WPAN may be a bluetooth network, IEEE 802.15x, or some other type of network. The techniques may also be implemented in conjunction with any combination of WWAN, WLAN and/or WPAN. These techniques may also be implemented in conjunction with femtocells.

Satellite Positioning Systems (SPS) typically include a transmitter system positioned so that entities can determine their own position on or above the earth based, at least in part, on signals received from the transmitter. Such transmitters typically transmit a signal marked with a repeating pseudo-random noise (PN) code having a set number of chips and may be located on ground-based control stations, user equipment, and/or space vehicles. In a particular example, such transmitters may be located on earth-orbiting Satellite Vehicles (SVs). For example, an SV in a constellation of a Global Navigation Satellite System (GNSS), such as the Global Positioning System (GPS), Galileo, GLONASS, or Compass, may transmit a signal labeled with a PN code that may be distinguished from PN codes transmitted by other SVs in the constellation (e.g., using a different PN code for each satellite as in GPS or the same code on a different frequency as in GLONASS). According to certain aspects, the techniques presented herein are not limited to global SPS systems (e.g., GNSS). For example, the techniques provided herein may be applied to or otherwise enabled for use in various regional systems, such as, for example, quasi-zenith satellite system (QZSS) over japan, Indian Regional Navigation Satellite System (IRNSS) over india, beidou over china, etc., and/or various augmentation systems (e.g., satellite-based augmentation systems (SBAS)) that may be associated with or otherwise enabled for use with one or more global and/or regional navigation satellite systems. By way of example and not limitation, the SBAS may include an augmentation system that provides integrity information, differential corrections, and the like, such as, for example, a Wide Area Augmentation System (WAAS), European Geostationary Navigation Overlay Service (EGNOS), a multi-function satellite augmentation system (MSAS), GPS assisted Geo augmented navigation, or GPS and Geo augmented navigation system (GAGAN), and/or the like. Thus, as used herein, an SPS may include any combination of one or more global and/or regional navigation satellite systems and/or augmentation systems, and SPS signals may include SPS signals, SPS-like signals, and/or other signals associated with such one or more SPS.

terminal/SET refers to devices such as cellular or other wireless communication devices, Personal Communication Systems (PCS) devices, Personal Navigation Devices (PNDs), Personal Information Managers (PIMs), Personal Digital Assistants (PDAs), laptop devices or other suitable mobile devices capable of receiving wireless communication and/or navigation signals. The terminal/SET is also intended to include devices that communicate with a Personal Navigation Device (PND), such as by short-range wireless, infrared, wired connection, or other connection, regardless of whether satellite signal reception, assistance data reception, and/or position-related processing occurs at the device or at the PND. Additionally, a terminal/SET is intended to include all devices, including wireless communication devices, computers, laptops, etc. which are capable of communication with a server, such as via the internet, Wi-Fi, or other network, and regardless of whether satellite signal reception, assistance data reception, and/or position-related processing occurs at the device, at a server, or at another device associated with the network. Any operable combination of the above is also considered a terminal/SET.

The methodologies described herein may be implemented by various means depending on the application. For example, these methodologies may be implemented in hardware, firmware, software, or any combination thereof. For an implementation involving hardware, the processing units may be implemented within one or more Application Specific Integrated Circuits (ASICs), Digital Signal Processors (DSPs), Digital Signal Processing Devices (DSPDs), Programmable Logic Devices (PLDs), Field Programmable Gate Arrays (FPGAs), processors, controllers, micro-controllers, microprocessors, electronic devices, other electronic units designed to perform the functions described herein, or a combination thereof.

For implementations involving firmware and/or software, the methodologies may be implemented with modules (e.g., procedures, functions, and so on) that perform the functions described herein. Any machine-readable medium tangibly embodying instructions may be used in implementing the methodologies described herein. For example, software codes may be stored in a memory and executed by a processing unit. The memory may be implemented within the processing unit or external to the processing unit. As used herein, the term "memory" refers to any type of long term, short term, volatile, nonvolatile, or other memory and is not to be limited to any particular type of memory or number of memories, or type of media upon which memory is stored.

If implemented in firmware and/or software, the functions may be stored on a computer-readable medium as one or more instructions or code. Examples include computer-readable media encoded with a data structure and computer-readable media encoded with a computer program. Computer-readable media includes physical computer storage media. A storage media may be any available media that can be accessed by a computer. By way of example, and not limitation, such computer-readable media can comprise RAM, ROM, EEPROM, CD-ROM or other optical disk storage, magnetic disk storage, semiconductor storage, or other memory devices, or any other medium that can be used to store desired program code in the form of instructions or data structures and that can be accessed by a computer; disk and disc, as used herein, includes Compact Disc (CD), laser disc, optical disc, Digital Versatile Disc (DVD), floppy disk and blu-ray disc where disks (disks) usually reproduce data magnetically, while discs (discs) reproduce data optically with lasers. Combinations of the above should also be included within the scope of computer-readable media.

In addition to being stored on a computer-readable medium, the instructions and/or data may also be provided as signals on a transmission medium included in the communication device. For example, the communication device may include a transceiver having signals indicative of instructions and data. The instructions and data are configured to cause one or more processing units to implement the functions outlined in the claims. That is, the communication device includes a transmission medium having signals indicative of information to perform the disclosed functions. At a first time, a transmission medium included in the communication device may include a first portion of information to perform the disclosed function, and at a second time, the transmission medium included in the communication device may include a second portion of information to perform the disclosed function.

The previous description of the disclosure is provided to enable any person skilled in the art to make or use the disclosure. Various modifications to the disclosure will be readily apparent to those skilled in the art, and the generic principles defined herein may be applied to other variations without departing from the scope of the disclosure. Thus, the disclosure is not intended to be limited to the examples and designs described herein but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

Claims (42)

1. A method of obtaining location services, comprising:

exchanging at least one message once between the terminal and the location server to establish an extended location session of a particular duration; and

obtaining, by the terminal, location services from the location server multiple times at any time within the particular duration of the extended location session as part of the extended location session.

2. The method of claim 1, wherein the exchanging at least one message comprises exchanging the at least one message to further configure at least one parameter for the extended location session, and wherein the obtaining location services comprises obtaining location services from the location server based on the at least one configured parameter.

3. The method of claim 2, wherein the at least one configured parameter comprises a selected positioning method, or a selected positioning protocol, or a quality of positioning (QoP), or a combination thereof.

4. The method of claim 1, wherein the exchanging at least one message comprises:

sending a first message from the terminal to the location server to initiate establishment of the extended location session, an

Receiving a second message sent by the location server to the terminal to confirm establishment of the extended location session.

5. The method of claim 4, wherein the first message comprises a requested duration of the extended location session, wherein the second message comprises a granted duration of the extended location session, and wherein the particular duration of the extended location session is equal to the granted duration.

6. The method of claim 4, wherein the first message comprises positioning capabilities of the terminal, and wherein the second message comprises positioning capabilities of the location server.

7. The method of claim 1, further comprising:

receiving a location service request from an application at the terminal, and wherein the extended location session is established by the terminal in response to the location service request.

8. The method of claim 1, further comprising:

receiving a location service request from an application external to the terminal, and wherein the extended location session is established by the terminal in response to the location service request.

9. The method of claim 1, further comprising:

a location request is received from an application at the terminal, and wherein the terminal obtains location services in response to the location request.

10. The method of claim 1, wherein the obtaining location services comprises:

sending a first message from the terminal to the location server to obtain a location service, an

Receiving a second message including location information from the location server.

11. The method of claim 10, wherein the first message comprises a request for assistance data, and wherein the location information in the second message comprises assistance data for the terminal.

12. The method of claim 10, wherein the first message comprises a measurement, and wherein the location information in the second message comprises a location estimate for the terminal.

13. The method of claim 10, wherein the first message comprises a positioning method selected by the terminal.

14. The method of claim 10, wherein the first message comprises at least one positioning message for a selected positioning protocol.

15. The method of claim 1, further comprising:

determining a session Identifier (ID) of the extended location session; and

using the session ID to identify messages exchanged between the terminal and the location server to obtain location services during the extended location session.

16. The method of claim 1, wherein the obtaining location services comprises:

obtaining location services by the terminal a plurality of times during the extended location session, an

Emulating a periodic triggered location service or an area event triggered location service using location information received by the terminal from the multiple obtained location service.

17. The method of claim 1, further comprising:

exchanging messages between the terminal and the location server to terminate the extended location session before expiration of the particular duration.

18. The method of claim 1, further comprising:

sending, from the terminal to the location server, a message requesting extension of the extended location session beyond the particular duration.

19. The method of claim 1, wherein the terminal is roaming away from a home network and communicating with a serving network, and wherein the location server is associated with the serving network.

20. The method of claim 1, wherein the terminal and the location server exchange Secure User Plane Location (SUPL) messages for the extended location session.

21. An apparatus for obtaining location services, comprising:

means for exchanging at least one message once between the terminal and the location server to establish an extended location session of a particular duration; and

means for obtaining, by the terminal, location services from the location server multiple times at any time within the particular duration of the extended location session as part of the extended location session.

22. The apparatus of claim 21, wherein the means for exchanging at least one message comprises means for exchanging the at least one message to further configure at least one parameter for the extended location session, and wherein the means for obtaining location services comprises means for obtaining location services from the location server based on the at least one configured parameter.

23. The apparatus of claim 21, wherein the means for exchanging at least one message comprises:

means for sending a first message from the terminal to the location server to initiate establishment of the extended location session, an

Means for receiving a second message sent by the location server to the terminal to confirm establishment of the extended location session.

24. The apparatus of claim 21, wherein the means for obtaining location services comprises:

means for sending a first message from the terminal to the location server to obtain a location service, an

Means for receiving a second message comprising location information from the location server.

25. The apparatus of claim 21, wherein the means for obtaining location services comprises:

means for obtaining location services by the terminal a plurality of times during the extended location session, an

Means for emulating a periodic triggered location service or an area event triggered location service using location information received by the terminal from the multiple obtained location services.

26. An apparatus for wireless communication, comprising:

at least one processing unit configured to exchange at least one message once between a terminal and a location server to establish an extended location session of a particular duration, and obtain location services from the location server by the terminal a plurality of times at any time within the particular duration of the extended location session as part of the extended location session.

27. The apparatus as recited in claim 26, said at least one processing unit configured to: exchanging the at least one message to further configure at least one parameter for the extended location session; and obtaining location services from the location server based on the at least one configured parameter.

28. The apparatus as recited in claim 26, said at least one processing unit configured to: sending a first message from the terminal to the location server to initiate establishment of the extended location session; and receiving a second message sent by the location server to the terminal to confirm establishment of the extended location session.

29. The apparatus as recited in claim 26, said at least one processing unit configured to: sending a first message from the terminal to the location server to obtain a location service; and receiving a second message including location information from the location server.

30. The apparatus as recited in claim 26, said at least one processing unit configured to: obtaining, by the terminal, a plurality of times during the extended location session, and emulating a periodic triggered location service or an area event triggered location service using location information received by the terminal from the plurality of obtained location services.

31. A method of supporting location services, comprising:

exchanging at least one message once between a location server and a terminal to establish an extended location session of a particular duration; and

as part of the extended location session, providing location services to the terminal by the location server multiple times when requested by the terminal at any time within the particular duration of the extended location session.

32. The method of claim 31, wherein the exchanging at least one message comprises exchanging the at least one message to further configure at least one parameter for the extended location session, and wherein the providing location services comprises providing location services to the terminal based on the at least one configured parameter.

33. The method of claim 31, wherein the exchanging at least one message comprises:

receiving a first message sent by the terminal to the location server to initiate establishment of the extended location session, an

Sending a second message from the location server to the terminal to confirm establishment of the extended location session.

34. The method of claim 31, wherein said providing location services comprises:

receiving a first message sent by the terminal to the location server to obtain location services, an

Sending a second message comprising location information from the location server to the terminal.

35. The method of claim 31, wherein the providing location services comprises providing location services to the terminal multiple times during the extended location session to enable the terminal to emulate a periodic triggered location service or an area event triggered location service.

36. The method of claim 31, further comprising:

exchanging messages between the location server and the terminal to terminate the extended location session before expiration of the particular duration.

37. The method of claim 31, further comprising:

receiving a message sent by the terminal to the location server requesting extension of the extended location session beyond the particular duration.

38. An apparatus for supporting location services, comprising:

means for exchanging at least one message once between a location server and a terminal to establish an extended location session of a particular duration; and

means for providing location services to the terminal by the location server multiple times when requested by the terminal at any time within the particular duration of the extended location session as part of the extended location session.

39. The apparatus of claim 38, wherein the means for exchanging the at least one message comprises means for exchanging the at least one message to further configure at least one parameter for the extended location session, and wherein the means for providing location services comprises means for providing location services to the terminal based on the at least one configured parameter.

40. The apparatus of claim 38, wherein the means for exchanging at least one message comprises:

means for receiving a first message sent by the terminal to the location server to initiate establishment of the extended location session, an

Means for sending a second message from the location server to the terminal to confirm establishment of the extended location session.

41. The apparatus of claim 38, wherein the means for providing location services comprises:

means for receiving a first message sent by the terminal to the location server to obtain location services, an

Means for sending a second message comprising location information from the location server to the terminal.

42. The apparatus of claim 38, wherein the means for providing location services comprises means for providing location services to the terminal multiple times during the extended location session to enable the terminal to emulate a periodic triggered location service or an area event triggered location service.