Method and apparatus for supporting positioning for terminals in a wireless network

Techniques for supporting positioning for terminals in a wireless network are described. In an aspect, positioning may be supported by a location server that can reside in different entities. In one design, the location server may obtain positioning information (e.g., measurements) for a target device via a common positioning protocol. The location server may use the common positioning protocol regardless of where it resides and may communicate with other entities via this protocol. The location server may determine location information (e.g., a location estimate) for the target device based on the positioning information. In another aspect, positioning may be supported by transporting multiple positioning messages together. In yet another aspect, positioning may be supported by transporting a positioning message containing multiple parts defined by different organizations. In yet another aspect, positioning may be supported with shared measurement data units and/or shared assistance data units that may be applicable for different positioning methods.

BACKGROUND

The present disclosure relates generally to communication, and more specifically to techniques for supporting positioning for terminals in a wireless network.

It is often desirable, and sometimes necessary, to know the location of a terminal, e.g., a cellular phone. The terms “location” and “position” are synonymous and are used interchangeably herein. For example, a location services (LCS) client may desire to know the location of the terminal and may communicate with a network server in order to request for the location of the terminal. The network server and the terminal may then exchange messages, as necessary, to obtain a location estimate for the terminal. The network server may then return the location estimate to the LCS client.

Different terminals may operate in different scenarios and may have different capabilities with regard to positioning. Positioning refers to a functionality that determines a geographical location of a target terminal. It may be desirable to flexibly support positioning for terminals with different capabilities.

SUMMARY

Techniques for supporting positioning for terminals in a wireless network are described herein. In an aspect, positioning may be supported by a location server that can reside in different entities. In one design, the location server may obtain positioning information (e.g., measurements, a coarse location estimate, etc.) for a target device via a common positioning protocol. The location server may reside in a network entity or may be co-located with (e.g., may be part of) the target device. The location server may use the common positioning protocol regardless of where it resides and may communicate with other entities via the common positioning protocol. The location server may determine location information (e.g., assistance data, a location estimate, etc.) for the target device based on the positioning information.

In another aspect, positioning may be supported by transporting multiple positioning messages together, which may improve efficiency and reduce delay. In one design, an entity (e.g., a location server, a positioning unit, or a target device) may exchange (e.g., send or receive) a plurality of positioning messages transported together in one message transaction. The plurality of positioning messages may be sent as linked messages or in a single container message. The entity may perform positioning based on the plurality of positioning messages.

In yet another aspect, positioning may be supported by transporting a positioning message containing multiple parts defined by different organizations. In one design, an entity may exchange a positioning message comprising a first part and a second part for a particular transaction type. The first part may include first information for positioning defined by a first organization, and the second part may include second information for positioning defined by a second organization. The entity may perform positioning based on the positioning message. For example, the entity may determine a location estimate based on the first information (e.g., measurements) in the first part as well as the second information (e.g., more measurements, or a coarse location estimate) in the second part.

In yet another aspect, positioning may be supported with shared measurement data units and/or shared assistance data units that may be applicable for different positioning methods. In one design, an entity may exchange a measurement data unit applicable for a first plurality of positioning methods. Each of the first plurality of positioning methods may be associated with a different set of applicable measurement data units. The entity may perform positioning based on the exchanged measurement data unit and in accordance with a positioning method, which may be one of the first plurality of positioning methods. Alternatively or additionally, the entity may exchange an assistance data unit applicable for a second plurality of positioning methods. Each of the second plurality of positioning methods may be associated with a different set of applicable assistance data units. The entity may perform positioning based on the exchanged assistance data unit and in accordance with the positioning method, which may be one of the second plurality of positioning methods.

DETAILED DESCRIPTION

FIG. 1shows a diagram of an exemplary deployment100supporting positioning. A target device (TD)110is an entity whose location is to be determined. Target device110may be stationary or mobile and may also be referred to as a terminal, a mobile station, a user equipment (UE), an access terminal, a SUPL enabled terminal (SET) in Secure User Plane Location (SUPL) from Open Mobile Alliance (OMA), a subscriber unit, a station, etc. Target device110may be a cellular phone, a personal digital assistant (PDA), a wireless device, a wireless modem, a wireless router, a laptop computer, a telemetry device, a tracking device, etc. Target device110may communicate with one or more base stations in a wireless network. Target device110may also communicate peer-to-peer with other terminals.

A reference source (RS)140is an entity that transmits a signal (e.g., a radio signal) that can be measured to support positioning. Reference source140may be a satellite in a Satellite Positioning System (SPS), which may be the United States Global Positioning System (GPS), the European Galileo system, the Russian GLONASS system, or some other SPS. Reference source140may also be a base station in a wireless network. A base station may also be referred to as an access point, a Node B, an evolved Node B (eNB), etc. A wireless network may be a Global System for Mobile Communications (GSM) network, a Wideband Code Division Multiple Access (WCDMA) network, a General Packet Radio Service (GPRS) access network, a Long Term Evolution (LTE) network, a CDMA 1X network, a High Rate Packet Data (HRPD) network, an Ultra Mobile Broadband (UMB) network, a wireless local area network (WLAN), etc. GSM, WCDMA, GPRS, and LTE are different radio technologies defined by an organization named “3rd Generation Partnership Project” (3GPP). CDMA 1X, HRPD and UMB are different radio technologies defined by an organization named “3rd Generation Partnership Project 2” (3GPP2). Reference source140may also be a broadcast station in a broadcast network, which may be a television network, a digital broadcast network, etc. Reference source140may also be part of a terminal, e.g., target device110. In general, one or more signals from one or more reference sources may be measured to determine the location of target device110. Only one reference source140is shown inFIG. 1for simplicity. The location of a reference source may be known or can be ascertained and may be used for positioning of target device110.

A positioning unit (PU)120is an entity that can measure signals from one or more reference sources, such as reference source140. Positioning unit120may also be able to compute a location estimate for target device110based on measurements obtained by positioning unit120. Positioning unit120may be part of target device110, or a separate device, or part of some other entity. The other entity may be another terminal, a base station, a specialized location measurement unit (LMU) in a wireless network, etc.

A location server (LS)130is an entity that can receive positioning information for a target device and determine location information for the target device. In general, positioning information may be any information used to support positioning. For example, positioning information may comprise measurements, a coarse location estimate, etc. Location information may be any information related to the location of a target device. For example, location information may comprise assistance data for making measurements of signals for positioning, a final location estimate for the target device, etc. Location server130may communicate with positioning unit120, receive positioning information from positioning unit120, and provide location information (e.g., assistance data) to positioning unit120. Location server130may also compute a location estimate for target device110based on measurements received from positioning unit120and provide the location estimate to positioning unit120. Location server130may reside in any one of a plurality of entities. For example, location server130may be a Serving Mobile Location Center (SMLC), a Standalone SMLC (SAS), an Evolved SMLC (E-SMLC), a SUPL Location Platform (SLP), a Position Determining Entity (PDE), etc. Location server130may also be part of a terminal, e.g., part of target device110. In one design, location server130may communicate with other entities (e.g., positioning unit120) via a common positioning protocol regardless of where location server130resides. The common positioning protocol may be LTE Positioning Protocol (LPP) used in LTE or some other positioning protocol.

FIG. 1shows four generic entities that can support positioning for target device110. Various configurations may be supported by the entities shown inFIG. 1. In one design, target device110and positioning unit120may be co-located. In this design, target device110may measure one or more signals from one or more reference sources for positioning of target device110. In another design, target device110and reference source140may be co-located. In this design, target device110may transmit a signal that may be measured and used for positioning of the target device. In yet another design, target device110may be co-located with location server130. In this design, target device110may receive measurements from positioning unit120and may perform positioning for target device110based on the measurements. In general, target device110may support positioning unit120and/or reference source140in order to measure other signals or have its own signal measured. Other configurations may also be supported by the entities shown inFIG. 1. For example, positioning unit120and location server130may be co-located. As another example, reference source140and location server130may be co-located.

FIG. 2Ashows a configuration supporting terminal-assisted and terminal-based positioning methods. In this configuration, positioning unit120is co-located with target device110. Positioning unit120may measure signals from reference sources such as a satellite140a, a base station140b, etc. Positioning unit120may send measurements and/or other information (e.g., a coarse or a fine location estimate) to location server130. Location server130may determine location information (e.g., assistance data) and may send the location information to positioning unit120(e.g., to assist positioning unit120to measure signals and possibly obtain a location estimate). Location server130may also determine a location estimate for target device110based on measurements and/or other information received from positioning unit120. Location server130may forward the location estimate to some external client (not shown inFIG. 2A) and/or to target device110. The configuration inFIG. 2Amay be used for terminal-assisted and terminal-based positioning methods such as assisted GNSS (A-GNSS), observed time difference (OTD), enhanced observed time difference (E-OTD), observed time difference of arrival (OTDOA), advanced forward link trilateration (A-FLT), etc.

FIG. 2Bshows a configuration supporting network-based positioning methods. In this configuration, reference source140is co-located with target device110, and positioning unit120is external to target device110. Positioning unit120may measure a signal from target device110. Positioning unit120may also receive measurements made by target device110for other reference sources (not shown inFIG. 2B). The measurements from target device110may be used to support handover of target device110and/or for other purposes. Positioning unit120may send the measurements and/or other information to location server130. Location server130may determine location information (e.g., assistance data) and may send the location information to positioning unit120(e.g., to assist positioning unit120to measure signals from reference source140). Location server130may also determine a location estimate for target device110based on measurements and/or other information received from positioning unit120. Location server130may forward the location estimate to some external client (not shown inFIG. 2B) and/or to target device110. The configuration inFIG. 2Bmay be used for network-based positioning methods such as enhanced cell identity (E-CID), uplink time difference of arrival (U-TDOA), etc.

For simplicity,FIGS. 2A and 2Bshow one positioning unit120and one or more reference sources140. In general, any number of positioning units may measure signals from any number of reference sources and may send their measurements to location server130. Target device110may act as a reference source for some measurements and/or as a positioning unit for other measurements.

FIGS. 2A and 2Bshow two configurations supporting non peer-to-peer (P2P) positioning. Non-P2P positioning may occur when reference source140, positioning unit120, and location server130are not co-located with (e.g., are not part of) any terminal that is not target device110. For non-P2P positioning, location server130may be a network entity or part of target device110, positioning unit120may be part of either target device110or a network entity, and reference source140may be part of either target device110or an external entity (e.g., a satellite, a base station, a broadcast station, etc.)

In one design, P2P positioning may be supported by the entities shown inFIG. 1. P2P positioning may occur when a first terminal assumes the role of location server130, or positioning unit120, or reference source140, or any combination thereof, in order to help position a second terminal that assumes the role of target device110. Different types of P2P positioning may be supported depending on where location server130, positioning unit120, and reference source140reside, or whether the first or second terminal assumes the role of each of the location server, the positioning unit, and the reference source.

FIG. 2Cshows a configuration supporting P2P positioning. In this configuration, a first terminal102is target device110and also assumes the roles of location server130and reference source140. A second terminal104communicates peer-to-peer with first terminal102and assumes the role of positioning unit120. Positioning unit120in terminal104may measure a signal from reference source140in terminal102and may send measurements and possibly other information to location server130in terminal102. Location server130may determine location information (e.g., assistance data) and may send the location information to positioning unit120(e.g., to assist positioning unit120to measure signals from reference source140). Location server130may also determine a location estimate for target device110based on measurements and/or other information received from positioning unit120. Location server130may forward the location estimate to some external client (not shown inFIG. 2C) and/or pass the location estimate to some entity (e.g., an application) in target device110.

For simplicity,FIG. 2Cshows terminal102communicating with one peer terminal104. In general, terminal102may communicate with any number of peer terminals and may request measurements from one or more peer terminals. Each peer terminal may act as a positioning unit and may measure the signal from terminal102. Each peer terminal may send measurements and its location to terminal102. The location of terminal102may be determined based on the measurements from all peer terminals and their reported locations.

FIG. 2Dshows another configuration supporting P2P positioning. In this configuration, a first terminal106is target device110and also assumes the roles of positioning unit120and location server130. A second terminal108communicates peer-to-peer with first terminal106and assumes the role of reference source140. Positioning unit120in terminal106may measure a signal from reference source140in terminal108and may send measurements and/or other information to location server130in terminal106. Location server130may also receive the location of terminal108. Location server130may determine location information (e.g., assistance data) and may transfer the location information to positioning unit120(e.g., to assist positioning unit120to measure signals from reference source140) in terminal108. Location server130may also determine a location estimate for target device110based on measurements and/or other information received from positioning unit120. Location server130may forward the location estimate to some external client (not shown inFIG. 2D) and/or pass the location estimate to some entity (e.g., an application) in target device110.

For simplicity,FIG. 2Dshows terminal106communicating with one peer terminal108. In general, terminal106may communicate with any number of peer terminals and may make measurements for one or more peer terminals. Each peer terminal may act as a reference source whose signal may be measured by terminal106. Each peer terminal may send its location to terminal106. The location of terminal106may be determined based on the measurements for all peer terminals and their reported locations.

For P2P positioning, the role of positioning unit120and location server130may be assumed by different terminals. To avoid ambiguity, a terminal initiating a location transaction may specify which end/terminal of the transaction will assume the role of each of the location server and the positioning unit. Each terminal may then assume the role specified by the initiating terminal.

P2P positioning may be used to position a terminal, as described above. P2P positioning may also be used to help position an access point for a femto cell, which may also be referred to as a home Node B (HNB), a home eNB (HeNB), etc. In this case, the access point may be treated like a terminal.

In one design, generic positioning methods (GPMs) may be used to support positioning of target devices. A generic positioning method is a positioning method that supports positioning for a target device with different types of reference sources using the same type of measurements and location computation procedure.

Table 1 lists some generic positioning methods that may be supported and provides a short description for each generic positioning method.

TABLE 1Generic Positioning MethodsGPMDescriptionUplink orEmploy time of arrival differences between either (i) signal of theDownlinksame reference source/target device measured at different positioningTimeunits (for uplink) or (ii) signals of different reference sources measuredDifferenceby a positioning unit/target device (for downlink). Use trilaterationBased GPMmethod to compute location of target device.PropagationEmploy measurements of propagation delay from a reference source toTime Baseda positioning unit with one of these entities being at a known locationGPMand the other entity being co-located with a target device. Usetrilateration method to compute location.DirectionEmploy measurements of signal direction from a reference source to aBased GPMpositioning unit, where the reference source may be part of the targetdevice and the positioning unit may be part of a network. Usetriangulation methods to compute location.Path LossEmploy measurements of signal strength of a reference source at aBased GPMpositioning unit to estimate distance between the reference source andthe positioning unit based on signal attenuation. Can use trilaterationmethod to compute location.RF PatternEmploy measurements of signal strength of either (i) the sameMatchingreference source co-located with a target device at differentGPMpositioning units or (ii) different network-based reference sources atthe same positioning unit co-located with the target device. Employpredetermined RF signal strength patterns over small geographic areasto determine the most likely location of the target device based onpattern matching.

Detection of the presence of a particular reference source, without measurement of a signal from the reference source, may also be included in one or more generic positioning methods listed in Table 1 to support cell ID or WLAN-based positioning. A combination of generic positioning methods may also be used for positioning, e.g., to improve accuracy.

In one design, a set of positioning method classes (PMCs) may be defined. A PMC may include a set of positioning methods defined by applying one or more generic positioning methods to a given type of reference source. Different types of reference sources may be used for positioning and may include LTE eNBs, LTE-capable terminals, CDMA 1X base stations, 1X-capable terminals, etc. For a given type of reference source, one or more specific positioning methods may be defined by applying one or more generic positioning methods to this reference source. For example, A-GPS may be obtained by applying downlink time difference based GPM to GPS reference sources, U-TDOA may be obtained by applying uplink time difference based GPM to a GSM reference source, E-CID may be obtained by applying direction based and/or RF pattern matching GPM to an LTE reference source, etc.

Each PMC may include one or more positioning methods. The positioning methods in each PMC may be related because they employ measurements of the same type of reference source. These measurements may overlap, and the same measurements may be usable for different positioning methods within the PMC. Assistance data used to enable measurements and/or location computation for positioning methods in the same PMC may also overlap (e.g., if the measurements also overlap). Overlapping measurements and assistance data may be used to more efficiently support several positioning methods within a PMC using a reduced set of measurements and assistance data. For example, measurements and assistance data that apply to multiple positioning methods may be transferred only once instead of for each positioning method.

FIG. 3shows a hierarchical structure300for a positioning protocol, which may be used by location server130. The positioning protocol may support a set of PMCs, which may be defined for different types of reference sources as described above. Each PMC may include a set of one or more positioning methods defined for a particular type of reference source. For example, an A-GNSS PMC may include A-GPS and A-Galileo positioning methods, a downlink LTE PMC may include OTDOA and E-CID positioning methods, an uplink LTE PMC may include E-CID positioning method, etc. Other PMCs may be defined for downlink WCDMA, uplink WCDMA, downlink CDMA 1X, uplink CDMA 1X, downlink WiMAX, uplink WiMAX, 802.11 Wi-Fi, sensors, etc.

A positioning method (PM) may be used to determine the location of a target device and may be associated with a particular generic positioning method and/or a particular reference source type. Each positioning method may support all or a subset of all measurements and assistance data applicable for its PMC. The set of measurements and assistance data supported by a given positioning method may be mandatory, or optional, or conditional for any positioning unit or location server supporting that positioning method.

A positioning unit or a location server that supports a given PMC may support at least one positioning method in that PMC. A positioning unit or a location server that supports a given positioning method may support all mandatory (and possibly optional and/or conditional) measurements and assistance data for that positioning method.

In one design, a set of measurement data units (MDUs) may be defined for all supported positioning methods. An MDU may be a collection of one or more items of data that may be used to report measurements and their attributes. An MDU may be applicable for one or more positioning methods within a particular PMC. An MDU may apply to multiple positioning methods and may be efficiently sent once to provide measurement data to these positioning methods (instead of separately for each positioning method). For example, MDU2inFIG. 3may apply to positioning methods PMa and PMb and may be sent once for these two positioning methods. An MDU may apply to one reference source and may be repeated for multiple reference sources of the same type, e.g., to provide or request pseudo-ranges for multiple satellites, timing differences for multiple base stations, etc.

MDUs may enable capabilities of location servers and positioning units to be defined, e.g., in terms of which MDUs a location server or positioning unit supports. MDUs may also enable location server130to request and positioning unit120to provide measurement data in a flexible and precise manner. Location server130may indicate certain characteristics (e.g., accuracy and response time) of an MDU when requesting it from positioning unit120. Positioning unit120may indicate the characteristics (e.g., accuracy) of an MDU that it is able to provide (e.g., via its capabilities).

In one design, a set of assistance data units (ADUs) may be defined for all supported positioning methods. An ADU may be a collection of one or more items of data that may be used to assist measurements. An ADU may be applicable for one or more positioning methods within a particular PMC. An ADU may apply to multiple positioning methods and may be efficiently sent once to provide assistance data to these positioning methods (instead of separately for each positioning method). For example, ADU d inFIG. 3may apply to positioning methods PMd and PMe and may be sent once for these two positioning methods. An ADU may apply to one reference source and may be repeated for multiple reference sources of the same type, e.g., to provide or request ephemeris data for multiple satellites within the same SPS, real time differences (RTDs) for multiple base stations of the same access type, etc.

ADUs may enable capabilities of location servers and positioning units to be defined, e.g., in terms of which ADUs a location server or positioning unit supports. ADUs may also enable positioning unit120to request and location server130to provide assistance data in a flexible and precise manner. Positioning unit120may indicate certain characteristics of an ADU (e.g., lifetime or accuracy for GPS ephemeris data) when requesting it from location server130.

In one design, PMCs, positioning methods, MDUs, and/or ADUs may be individually identified. This identification may facilitate capabilities, specific measurements, and specific assistance data to be requested and provided. Identification may also be useful to identify the presence of a particular MDU or ADU in a positioning message, to identify a message segment related to a specific positioning method or PMC, etc. The identities of PMCs may be unique across the positioning protocol whereas the identities of positioning methods, MDUs, and ADUs may be unique only for a particular PMC. Different ranges of IDs may be used for identification. For example, PMC ID of 0 may be reserved for possible future signaling applicable to all PMCs, PMC IDs of 1 to 63 may be used for network-based (uplink) PMCs, PMC IDs of 64 to 127 may be used for terminal-assisted and terminal-based (downlink) PMCs, PMC IDs of 128 to 191 may be used for operator specific positioning methods, PMC IDs of 192 to 254 may be used for vendor specific positioning methods, and PMC ID of 255 may be used to indicate PMC IDs greater than 255, if needed. In general, IDs may be defined in any suitable manner for PMCs, positioning methods, MDUs, and/or ADUs.

In one design, calibration PMCs may be used to provide calibration data to a location server for one or more reference sources. Calibration data may be for (i) signal timing and/or signal strength for base stations, access points, and/or other reference sources, (ii) timing and navigation data for GNSS systems, and/or (iii) other signals and data. Calibration data may be used by a location server to obtain assistance data that can be provided later to a positioning unit to assist it in making measurements to locate a target device. As an example, calibration data that includes transmission timing differences between nearby base stations may be used by a location server to derive assistance data (e.g., including approximate time differences between nearby base stations that a target device would be expected to measure) for downlink time difference positioning methods such as OTDOA. Such assistance data may then be sent later to a position unit co-located in the target device. A calibration PMC (or a calibration positioning method) may support a corresponding normal PMC (or normal positioning method) as described in the example above by helping obtain assistance data for the normal PMC (or normal positioning method) and by helping to compute a location estimate for any positioning method in the normal PMC. For example, a calibration PMC for inter-eNB timing measurement may support a downlink LTE PMC including OTDOA and E-CID positioning methods.

The use of calibration PMCs as part of a common positioning protocol that also supports normal PMCs may allow the common positioning protocol to be used to calibrate reference sources and thereby avoid the need for additional protocols for this purpose. A calibration PMC may not directly support any positioning methods, any ADUs, and positioning of target devices. A calibration PMC may support MDUs, which may be provided by positioning units (e.g., base stations or LMUs) for reference sources applicable to the corresponding normal PMC. The MDUs may be used by the location server to help obtain ADUs for the corresponding normal PMC as well as to help compute a location estimate for the position methods in the corresponding normal PMC.

In one design, location server130and target device110(or location server130and positioning unit120) may engage in a location session in order to obtain measurements or location, to provide assistance data, and/or for other purposes. A location session may also be referred to as an LPP session, a positioning session, etc. A location session may include one or more transactions, which may also be referred to as LPP transactions, etc. Each transaction may cover a particular operation such as exchange of capabilities, transfer of assistance data, transfer of location information, etc. Each transaction may be assigned a transaction ID, and all messages for that transaction may include the transaction ID in order to link the messages to the same transaction.

In one design, a set of positioning messages may be defined and used for communication between location servers and other entities. The positioning messages may also be referred to as LPP messages, LPP protocol data units (PDUs), etc.

FIG. 4Ashows a design of a positioning message400. In this design, positioning message400includes a positioning protocol version field410, a transaction ID field412, a transaction end flag field414, a message type field416, and N information elements420athrough420n, where N may be zero or greater. Field410may indicate which version of the positioning protocol is used for a location session and may be included to negotiate the use of the same positioning protocol version by two entities engaging in the location session. An originating entity may set field410to the highest version that it supports. A receiving entity may return the highest version that it supports. The negotiated version may be the lower of the two highest versions supported by the two entities.

Field412may identify a transaction for which the positioning message applies. Field412may be especially pertinent when multiple transactions occur concurrently during the location session. Each transaction may be assigned a unique transaction ID. In one design, an originating entity that initiates a transaction may assign a transaction ID for that transaction. A responding entity may use the same transaction ID when responding to the originating entity. For example, location server130may assign transaction IDs to transactions initiated by location server130, and positioning unit120may assign transaction IDs to transactions initiated by positioning unit120. When more than one location servers are used to position target device110, each location server may be allocated a different range of transaction IDs that can be assigned by that location server.

Field414may indicate whether the sending entity has terminated the transaction. Field416may indicate the type of message being sent. A set of message types may be supported as described below, and positioning message400may be of the type indicated by field416.

Fields420athrough420nmay include information that may be dependent on the message type. Each field420may carry a positioning data component (PDC) for one PMC or positioning method. Positioning message400may include multiple PDCs to efficiently convey information for more than one PMC at a time and to invoke combined/hybrid positioning.

A positioning message may also include different and/or other fields besides the fields shown inFIG. 4A. For example, a positioning message may include a field for session ID, a field to indicate whether the sender is acting as a location server or a positioning unit, etc.

Table 2 lists a set of positioning message types that may be supported in accordance with one design.

TABLE 2Positioning Message TypeMessage TypeDescriptionRequest CapabilitiesMessage to request for capabilities of an entity forpositioning protocol and positioning methods.Provide CapabilitiesMessage to provide capabilities of an entity forpositioning protocol and positioning methods.Request AssistanceMessage to request for assistance data.DataProvide AssistanceMessage to provide assistance data.DataRequest LocationMessage to request for location information.InformationProvide LocationMessage to provide location information.Information

Location server130may provide its capabilities when requested by positioning unit120or may send its capabilities unilaterally without receiving any request. Similarly, positioning unit120may provide its capabilities when requested by location server130or may send its capabilities unilaterally without receiving any request. The capabilities of an entity (e.g., location server130or positioning unit120) may include the PMCs and positioning methods supported by that entity and the capabilities of the entity for each supported positioning method (e.g., a list of MDUs that can be sent or received by the entity and/or a list of ADUs that can be sent or received by the entity).

Location server130may provide assistance data when requested by positioning unit120or may send the assistance data unilaterally without receiving any request. The assistance data may assist positioning unit120to make measurements that may be used for positioning of target device110or for calibration of reference source140. Location server130may also provide assistance data when the data changes for an ongoing positioning method. This automatic update of assistance data may enable the positioning method to be reset without having to explicitly abort and restart it. For example, target device110may change serving cell (e.g., due to handover) during an OTDOA positioning method, and location server130may send new assistance data applicable for the new serving cell in order for positioning unit120(in target device110) to obtain and transfer measurements of different neighbor base stations associated with the new serving cell. As another example, positioning unit120(e.g., an LMU) may measure data and/or signaling channels transmitted by target device110in a particular serving cell for U-TDOA positioning, and target device110may change serving cell (e.g., due to handover). Location server130may then send new assistance data to positioning unit120to enable it to measure different data and/or signaling channels associated with the new serving cell. Having automatic update may be useful in these scenarios.

Positioning unit120may send positioning information to location server130to support positioning of target device110(e.g., for a normal PMC) or determination of assistance data for future positioning (e.g., for a calibration PMC). The positioning information may comprise (i) measurements made by positioning unit120within target device110for other reference sources (e.g., as shown inFIG. 2A), (ii) measurements made by positioning unit120external to target device110for reference source140in target device110(e.g., as shown inFIG. 2B), (iii) a location estimate for target device110obtained by positioning unit120, and/or (iv) other information related to the location of target device110. Location server130may send location information comprising a location estimate for target device110to positioning unit120, e.g., if positioning unit120is part of target device110and target device110is the intended final recipient of the location estimate. For calibration of a reference source, positioning information may comprise measurements made by positioning unit120for network-based reference sources (e.g., base stations) and other resources (e.g., satellites).

A positioning message may also include a field for common parameters applicable for all PMCs supported by the positioning message. The common parameters for a Request Capabilities message and a Provide Capabilities message may include a list of supported PMC IDs, PMC versions, etc. The common parameters for a Request Assistance Data message may include an approximate location of a target device, an indication of whether periodic or triggered assistance data is requested and associated parameters, primary access (e.g., a serving cell ID), secondary accesses (e.g., neighboring cell IDs), etc. The common parameters for a Provide Assistance Data message may include an approximate location of a target device, current time, etc. The common parameters for a Request Location Information message may include required quality-of-service (QoS) (e.g., for location, measurement accuracy, and/or response time), an indication of whether periodic or triggered location information is requested and associated parameters, location type for terminal-assisted and/or terminal-based positioning methods, a list of required or preferred PMC IDs and PMC versions, etc. The common parameters for a Provide Location Information message may include a location estimate and accuracy, time, velocity, etc.

FIG. 4Bshows a design of a positioning message450that includes multiple parts defined by different organizations. Positioning message450may include a positioning protocol version field, a transaction ID field, a transaction end flag field, a message type field, and N information elements, as described above forFIG. 4A. In one design, one part may be sent in each information element. For example, a first part may comprise first information for positioning defined by a first organization, a second part may comprise second information for positioning defined by a second organization, etc. An organization may be 3GPP, 3GPP2, OMA, Internet Engineering Task Force (IETF), Institute of Electrical and Electronics Engineers (IEEE), a network operator, an equipment vendor, etc. The multiple parts may be for a particular transaction type, e.g., capability transfer, assistance data transfer, location information transfer, etc. This design may allow an external organization to enhance an existing positioning method or support new positioning methods by defining additional capabilities that may be carried in one or more additional parts of a positioning message.

In one design, several related transactions may be invoked in parallel. For example, positioning unit120may be co-located with target device110(e.g., as shown inFIG. 2A) and may request for its own location from location server130, request for assistance data from location server130, and provide its capabilities to location server130to enable location server130to obtain its location. As another example, positioning unit120may be co-located with target device110and may request for its own location from location server130and may provide measurements for one or more positioning methods (e.g., E-CID and/or A-GNSS) to location server130to enable location server130to derive a location estimate. The messages sent by positioning unit120to location server130in both examples above may also be combined. As yet another example, location server130may request for positioning information from positioning unit120, which may be co-located with target device110, and may provide assistance data to positioning unit120to help obtain the positioning information.

In one design, multiple positioning messages for multiple transactions may be transported together in one message transaction/exchange. In one design, a single container message may include the multiple positioning messages. For example, the container message may be a predefined positioning message that can carry the multiple positioning messages in multiple information elements, one information element for each individual positioning message. In another design, the multiple positioning messages may be linked and sent separately, either serially or in parallel. A common identifier may be included in each message to enable the separate messages to be associated at a receiving entity. The multiple positioning messages may also be transported together in other manners. The format and content of each positioning message may not be dependent on whether that positioning message is sent alone or with other positioning messages.

A sending entity may send a container message including multiple positioning messages for multiple transactions. A recipient entity may generate individual replies for the multiple transactions and may use the association of the multiple positioning messages to provide more appropriate responses, e.g., by making use of the information contained in all received positioning messages to generate the reply to each received message. The recipient entity may return a container message including multiple positioning messages for the individual replies. Transporting multiple positioning messages together may provide various advantages such as (i) reduce delay and avoid problems due to delivery of positioning messages out of order if sent separately and (ii) ensure that a receiving entity is in possession of the most information needed to process and reply to each received message.

FIG. 5shows a message flow500for a mobile-originated location request (MO-LR) service in LTE. An LCS client in a UE510or a user of UE510may request for location service, e.g., to retrieve the location of UE510or to transfer the UE location to a third party. UE510may send an MO-LR request message to a Mobility Management Entity (MME)540via a serving eNB520(step1). The MO-LR request message may be used as a container message to carry one or more positioning messages to instigate one or more procedures. For example, the MO-LR request message may include a positioning message to provide capabilities of UE510, a positioning message to request for assistance data, a positioning message to provide measurements, etc. MME540may send a location request message to an E-SMLC530(step2). The location request message may include any positioning message received by MME540in step1.

E-SMLC530and UE510may engage in a location session and may perform one or more transactions (step3). For this location session, UE510may be a target device and a positioning unit, and E-SMLC530may be a location server. E-SMLC530may instigate one or more transactions to obtain positioning capabilities of UE510, provide assistance data to UE510, and/or obtain positioning information from UE510. After the first positioning message is received from E-SMLC530, UE510may instigate one or more transactions to request for assistance data, to request for further assistance data, etc.

E-SMLC530and eNB520may engage in a location session and may perform one or more transactions (step4). For this location session, eNB520may be a positioning unit, and E-SMLC530may be a location server. E-SMLC530may obtain positioning information for UE510from eNB520via the location session. Steps3and4may occur in any order or in parallel. E-SMLC530may return a location response message to MME540(step5). The location response message may include any location estimate obtained from steps3and4and/or a final positioning message, which may provide a location estimate if requested by UE510in step1. If UE510requested location transfer to a third party, then MME540may transfer the location estimate received from E-SMLC530to the third party (step6). MME540may send to UE510an MO-LR response message that may carry any final positioning message received in step5and/or a separate location estimate (step7).

For control plane location solution, a network entity (e.g., MME540) may need to request for location service from a location server (e.g., E-SMLC530) before a location session can occur. For MO-LR service, a target device (e.g., UE510) may first send an MO-LR request message to the network entity to request for location service. The target device may then wait for a response from the network entity and may thereafter send a first positioning message to the location server. This extra delay may be avoided by having the target device include the first positioning message in the MO-LR request message sent to the network entity. The network entity may then transfer this first positioning message to the location server in the location request message. Subsequent positioning messages may be sent more directly between the target device and the location server without making use of a Non Access Stratum (NAS) layer in which the MO-LR request message belongs. A final positioning message from the location server may be sent either directly to the target device or via an MO-LR response message, which may reduce the total number of messages to transfer.

FIG. 6shows a message flow600for a location session with multiple transactions. Message flow600may be used for the location session in step3and/or the location session in step4inFIG. 5. Target device110may send an MO-LR request message to location server130(step1). The MO-LR request message may carry one or more positioning messages to instigate one or more procedures. A positioning message may include the required QoS, whether triggered or periodic location is requested, and/or other information. Location server130may send a positioning message to request for positioning capabilities of target device110, if the positioning capabilities are not received in step1(step2). Target device110may return a positioning message with its positioning capabilities, e.g., supported positioning methods (step3).

Location server130may send a positioning message to a request for positioning information, e.g., location-related measurements for the positioning methods supported by target device110(step4). Target device110may send a positioning message to request for assistance data (step5). Location server130may return a positioning message with the requested assistance data (step6). Location server130may also send one or more follow on positioning messages with updated assistance data (not shown inFIG. 6), e.g., when triggered by changes or at a periodic interval. Target device110may obtain the positioning information (e.g., measurements) and may send a positioning message with the positioning information (step7). Target device110may also send one or more follow-on positioning messages with updated location information (not shown inFIG. 6), e.g., when triggered by changes or at a periodic interval. Location server130may compute a location estimate for target device110using the positioning information received in step7. Location server130may then send an MO-LR response message, which may include a positioning message and/or the location estimate, to target device110(step8). Location server130may also send one or more follow on positioning messages with updated location estimates (not shown inFIG. 6), e.g., when triggered by certain events, or at a periodic interval, or after receiving further positioning information from the target device, etc.

FIG. 6shows an exemplary location session with three explicit transactions A, B and C. In general, a location session may include any number of transactions and any type of transaction. Multiple transactions of the same type may also be performed. For example, a transaction to obtain positioning information from a target device to support E-CID positioning may be performed to obtain an approximate location, and a separate A-GNSS associated transaction may be performed in parallel or subsequently to obtain an accurate location.

FIG. 6shows a message flow for an MO-LR service. A message flow for a mobile-terminated location request (MT-LR) service may be defined with steps2through7inFIG. 6.

As shown inFIG. 6, a number of transactions may be performed. A transaction may involve a pair of positioning messages exchanged between a positioning unit in a target device110and location server130, as shown inFIG. 6. A transaction may also involve a single positioning message sent unilaterally by one entity. For example, a positioning unit in target device110may unilaterally provide its capabilities without receiving a request for capabilities, and location server130may unilaterally provide assistance data without receiving a request for assistance data. Multiple positioning messages for multiple transactions may be aggregated and transferred together. For example, the positioning messages in steps2and4may be transferred together, the positioning messages in steps3and5may be transferred together, etc.

FIG. 7shows a design of a process700for supporting positioning by a location server. The location server may obtain positioning information for a target device via a common positioning protocol, which may be LPP or some other positioning protocol (block712). The location server may reside at one of a plurality of possible entities, and the target device may be one of these entities. For example, the location server may reside in a network entity or may be co-located with the target device. The location server may use the common positioning protocol regardless of where it resides and may communicate with other entities via the common positioning protocol. The common positioning protocol may simply mean that the same positioning protocol is used regardless of where the location server resides. The location server may determine location information for the target device (block714).

In one design, the positioning information may comprise measurements for at least one reference source. For example, the location server may obtain measurements for at least one signal from at least one satellite, or at least one base station, or at least one terminal, or the target device, or some other entity, or a combination thereof. The location information may comprise a location estimate for the target device, which may be determined by the location server based on the measurements. In another design, the positioning information (i) may be indicative of the location of the target device, e.g., may comprise a coarse or a fine location estimate, or (ii) may comprise measurements of references sources that can be received at the location of the target device. The location information may comprise assistance data determined by the location server based on the positioning information. In yet another design, the location information may comprise assistance data, and the positioning information may comprise measurements made based on the assistance data. In general, the positioning information may comprise measurements, a location estimate, etc. The location information may comprise a location estimate, assistance data, etc. The two steps inFIG. 7may be performed in the order shown inFIG. 7, or in the opposite order. The location information may be determined based on the positioning information, or vice versa.

In one design, a positioning unit for the target device may determine the positioning information, e.g., make measurements. The positioning unit may reside at one of a second plurality of possible entities, and the target device may be one of these entities. The location server may communicate with the positioning unit via the common positioning protocol. For example, the location server may exchange capabilities, or assistance data, or location information, or a combination thereof with the positioning unit via the common positioning protocol.

FIG. 8shows a design of a process800for supporting positioning by an entity, which may be a target device, or a positioning unit, or some other entity. The entity may send positioning information for a target device to a location server via a common positioning protocol (block812). The location server may reside at one of a plurality of possible entities and may use the common positioning protocol regardless of where it resides. The target device may be one of the plurality of possible entities. The entity may receive location information for the target device from the location server (block814).

In one design, the positioning information may comprise measurements for at least one reference source, and the location information may comprise a location estimate for the target device determined by the location server based on the measurements. In another design, the positioning information may comprise measurements of references sources that can be received at the location of the target device, and the location information may comprise assistance data determined by the location server based on the positioning information. In yet another design, the location information may comprise assistance data, and the positioning information may comprise measurements made based on the assistance data. In this design, block812may occur after block814.

In one design, the entity may measure at least one signal from at least one reference source to obtain the measurements. In one design, the at least one reference source may comprise at least one satellite, or at least one base station, or at least one terminal, or a combination thereof. In this design, the measurements may be made at the target device. In another design, the at least one reference source may comprise the target device and possibly other reference sources. In this design, the measurements may be made at a positioning unit that is external to the target device.

FIG. 9shows a design of a process900for supporting positioning by an entity, which may be a location server, a positioning unit, a target device, or some other entity. The entity may exchange (e.g., send or receive) a plurality of positioning messages transported together in one message transaction (block912). In one design, the entity may send the plurality of positioning messages as linked messages or in a single container message. In another design, the entity may receive the plurality of positioning messages, which may be sent as linked messages or in a single container message. The entity may perform positioning based on the plurality of positioning messages (block914).

In one design, the plurality of positioning messages may be sent with an MO-LR message by the target device to initiate positioning. In another design, the plurality of positioning messages may be sent by a location server and may comprise (i) a first positioning message carrying assistance data and (ii) a second positioning message requesting for location information. In yet another design, the plurality of positioning messages may be sent to the location server (e.g., by the positioning unit or the target device) and may comprise (i) a first positioning message requesting for assistance data and (ii) a second positioning message carrying measurements. The plurality of messages may also include some other combination of messages.

In one design, each of the plurality of positioning messages may be of one of a plurality of message types, which may include a request capabilities message type, a provide capabilities message type, a request assistance data message type, a provide assistance data message type, a request location information message type, and a provide location information message type. The plurality of positioning messages may include positioning messages of at least two message types.

FIG. 10shows a design of a process1000for supporting positioning by an entity, which may be a location server, a positioning unit, a target device, or some other entity. The entity may exchange a positioning message comprising a first part and a second part for a particular transaction type (block1012). The first part may comprise first information for positioning defined by a first organization, and the second part may comprise second information for positioning defined by a second organization. For example, the first organization may comprise 3GPP or some other organization. The second organization may comprise 3GPP2, OMA, IETF, IEEE, a network operator, an equipment vendor, or some other organization. The entity may perform positioning based on the positioning message (block1014).

In one design of block1012, the entity may be a target device sending the positioning message to, or receiving the positioning message from, a location server. In another design, the entity may be a location server sending the positioning message to, or receiving the positioning message from, a target device.

In one design of block1014, the entity may determine assistance data or a location estimate based on the first information (e.g., measurements) in the first part and the second information (e.g., more measurements, or a coarse location estimate) in the second part. In another design, the entity may make measurements based on the first information (e.g., assistance data for satellites) in the first part and the second information (e.g., assistance data for base stations) in the second part.

FIG. 11shows a design of a process1100for supporting positioning by an entity, which may be a location server, a positioning unit, a target device, or some other entity. The entity may exchange a measurement data unit applicable for a first plurality of positioning methods, with each of the first plurality of positioning methods being associated with a different set of applicable measurement data units (block1112). For example, the exchanged measurement data unit may be MDU2inFIG. 3, the first plurality of positioning methods may include PMa and PMb, positioning method PMa may be associated with a first set of MDUs1,2and3, and positioning method PMb may be associated with a second set of MDUs2and3. The entity may perform positioning based on the exchanged measurement data unit and in accordance with a positioning method, which may be one of the first plurality of positioning methods (block1114).

Alternatively or additionally, the entity may exchange an assistance data unit applicable for a second plurality of positioning methods, with each of the second plurality of positioning methods being associated with a different set of applicable assistance data units (block1116). The entity may perform positioning based on the exchanged assistance data unit and in accordance with the positioning method, which may be one of the second plurality of positioning methods (block1118).

In general, only shared measurement data units may be supported, or only shared assistance data units may be supported, or both shared measurement and assistance data units may be supported. If only shared measurement data units are supported, then blocks1112and1114may be performed, and blocks1116and1118may be omitted. If only shared assistance data units are supported, then blocks1116and1118may be performed, and blocks1112and1114may be omitted. If both shared measurement and assistance data units are supported, the blocks1112to1118may be performed.

FIG. 12shows a block diagram of a design of target device110, a base station122, and location server130. Target device110may be a UE, a SET, etc. Location server130may be an SMLC, an E-SMLC, an SLP, etc. Positioning unit120may reside in target device110, base station122, or some other entity. Reference source140may be part of base station122, or a satellite, or some other entity. For simplicity,FIG. 12shows only one controller/processor1220, one memory1222, and one transmitter/receiver (TMTR/RCVR)1224for target device110, only one controller/processor1230, one memory1232, one transmitter/receiver1234, and one communication (Comm) unit1236for base station122, and only one controller/processor1240, one memory1242, and one communication unit1244for location server130. In general, each entity may include any number of processing units (processors, controllers, etc.), memories, transmitters/receivers, communication units, etc.

On the downlink, base station122may transmit data, signaling, and pilot to terminals within its coverage area. These various types of information may be processed by processing unit1230, conditioned by transmitter1234, and transmitted on the downlink. At target device110, downlink signals from base station122and other base stations may be received and conditioned by receiver1224and further processed by processing unit1220to obtain various types of information. Processing unit1220may perform process800inFIG. 8, process900inFIG. 9, process1000inFIG. 10, process1100inFIG. 11, and/or other processes for the techniques described herein. Memories1222and1232may store program codes and data for target device110and base station122, respectively. On the uplink, target device110may transmit data, signaling, and pilot to base station122. These various types of information may be processed by processing unit1220, conditioned by transmitter1224, and transmitted on the uplink. At base station122, the uplink signals from target device110and other terminals may be received and conditioned by receiver1234and further processed by processing unit1230to obtain various types of information from the terminals. Base station122may directly or indirectly communicate with location server130via communication unit1236.

Within location server130, processing unit1240may perform processing to support location services and positioning for terminals. For example, processing unit1240may perform process700inFIG. 7, process800inFIG. 8, process900inFIG. 9, process1000inFIG. 10, process1100inFIG. 11, and/or other processes for the techniques described herein. Processing unit1240may also compute location estimates for target device110, provide location information, etc. Memory1242may store program codes and data for location server130. Communication unit1244may allow location server130to communicate with base station122and/or other network entities. Location server130and target device110may exchange positioning messages via base station122and other network entities (not shown).

Positioning unit120may reside in terminal110, or base station122, or location server130. In this case, the processing by positioning unit120may be performed by processing unit1220,1230, or1240, respectively. Positioning unit120may also be external to the entities shown inFIG. 12. In this case, positioning unit120may include one or more processing units (processors, controllers, etc.), memories, transmitters/receivers, communication units, etc., that can perform the required functions.

Position 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 term “network” and “system” are often used interchangeably. A 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 and so on. A CDMA network may implement one or more radio access technologies (RATs) such as cdma2000, Wideband-CDMA (W-CDMA), and so on. Cdma2000 includes 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 “3rd Generation Partnership Project” (3GPP). Cdma2000 is described in documents from a consortium named “3rd Generation Partnership Project 2” (3GPP2). 3GPP and 3GPP2 documents are publicly available. A WLAN may be an IEEE 802.11x network, and a WPAN may be a Bluetooth network, an 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.

A satellite positioning system (SPS) typically includes a system of transmitters positioned to enable entities to determine their location on or above the Earth based, at least in part, on signals received from the transmitters. Such a transmitter typically transmits a signal marked with a repeating pseudo-random noise (PN) code of 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, a SV in a constellation of Global Navigation Satellite System (GNSS) such as Global Positioning System (GPS), Galileo, Glonass or Compass may transmit a signal marked with a PN code that is distinguishable from PN codes transmitted by other SVs in the constellation (e.g., using different PN codes for each satellite as in GPS or using the same code on different frequencies as in Glonass). In accordance with certain aspects, the techniques presented herein are not restricted to global systems (e.g., GNSS) for SPS. For example, the techniques provided herein may be applied to or otherwise enabled for use in various regional systems, such as, e.g., Quasi-Zenith Satellite System (QZSS) over Japan, Indian Regional Navigational Satellite System (IRNSS) over India, Beidou over China, etc., and/or various augmentation systems (e.g., an Satellite Based Augmentation System (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 but not limitation, an SBAS may include an augmentation system(s) that provides integrity information, differential corrections, etc., such as, e.g., Wide Area Augmentation System (WAAS), European Geostationary Navigation Overlay Service (EGNOS), Multi-functional Satellite Augmentation System (MSAS), GPS Aided 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, SPS-like, and/or other signals associated with such one or more SPS.

In addition to storage on computer-readable medium, instructions and/or data may be provided as signals on transmission media included in a communication apparatus. For example, a communication apparatus 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 apparatus includes transmission media with signals indicative of information to perform disclosed functions. At a first time, the transmission media included in the communication apparatus may include a first portion of the information to perform the disclosed functions, while at a second time the transmission media included in the communication apparatus may include a second portion of the information to perform the disclosed functions.