HK1145205B

HK1145205B - Delayed radio resource signaling in a mobile radio network

Info

Publication number: HK1145205B
Application number: HK10111712.2A
Authority: HK
Inventors: K．A．伯洛格斯; T．K．罗兰德; J．D．小迪洛奇
Original assignee: 高通股份有限公司
Priority date: 2007-09-11
Filing date: 2008-09-11
Publication date: 2015-07-10

Description

Delayed radio resource signalling in a mobile radio network

Cross Reference to Related Applications

This application claims the priority of provisional U.S. patent application 60/971,453 (attorney docket No. 072346P1) entitled "GSM Control Plane Positioning Preemption RRLP Implementation for MS and SMLC" filed on 35u.s.c. § 119(e) on 9, 11, 2007 and provisional U.S. patent application 61/012,039 (attorney docket No. 072346P2) entitled "GSM Control Plane Positioning Preemption RRLP Implementation for MS and SMLC" filed on 12, 6, 2007, the disclosures of both provisional applications being expressly incorporated herein by reference in their entirety.

Background

Technical Field

The present invention relates generally to communication systems, and more particularly to enhancing position location using a global navigation satellite system.

Background

It is often desirable and sometimes necessary to know the location of a mobile station (e.g., a cellular telephone). The terms "position" and "location" are synonymous and are used interchangeably herein. For example, a user may utilize a Mobile Station (MS) to browse a web site and may click on location-sensitive content. The location of the mobile station may then be determined and used to provide the appropriate content to the user. There are many other scenarios in which it is useful or necessary to know the location of a mobile station. For example, the FCC's 911 mandate requires operators to provide enhanced 911 services, including geographically locating mobile stations making 911 emergency service calls. A mobile station may be provisioned such that it can obtain location services from the home network and vice versa when roaming in a visited network. The mobile station may communicate with various network entities in the home network to determine the location of the mobile station whenever needed.

There are many different types of techniques used in calculating the position of a mobile station in a wireless network with various levels of success and accuracy. Network-based methods include using angles of arrival (AOAs) of at least two towers, using time difference of arrival (TDOA) of multilateration, and using RF fingerprinting to match the location signature of the RF pattern exhibited by the mobile station at a known location. Various mobile station-based approaches incorporate GPS, advanced forward link trilateration (a-FLT), timing advance/network measurement reporting (TA/NMR), and/or enhanced observed time difference (E-OTD).

Another mobile station-based approach is assisted-GPS (a-GPS), in which a server provides assistance data to a mobile station to make it have a lower time-to-first-lock (TTFF), permit weak signal acquisition, and optimize mobile station battery usage. a-GPS is used as a positioning technique, either alone or mixed with other positioning techniques that provide range-like measurements. The a-GPS server provides data to the wireless mobile station that is specific to the approximate location of the mobile station. The assistance data helps the mobile station to quickly lock onto the satellite and potentially enable the handset to lock onto weak signals. The mobile station then performs a position calculation or optionally returns the measured code phase to the server for such calculation. The a-GPS server may utilize additional information such as round trip timing measurements from the cellular base station to the mobile station to calculate a position fix that it may otherwise be unable to make; for example when there are not enough GPS satellites visible.

Advancements in satellite-based Global Positioning System (GPS), Timing Advance (TA), and ground-based enhanced observed time difference (E-OTD) position fix techniques have enabled the precise determination of the geographic location (e.g., latitude and longitude) of a mobile station. With the deployment of geolocation services within a wireless communications network, such location information may be stored in network elements and delivered to nodes in the network using signaling messages. Such information may be stored in a Serving Mobile Location Center (SMLC), a standalone SMLC (sas), a Position Determination Entity (PDE), a secure user plane location platform (SLP), and a dedicated mobile subscriber location database.

An example of a private mobile subscriber location database is the SMLC proposed by the third generation partnership project (3 GPP). In particular, 3GPP has defined a signaling protocol for conveying mobile subscriber location information to and from the SMLC. This signaling protocol is called the radio resource LCS (location services) protocol, denoted RRLP, and defines signaling messages communicated between the mobile station and the SMLC relating to the location of the mobile subscriber. A detailed description of the RRLP protocol is given in 3GPP TS 44.031v7.9.0(2008-06) third generation partnership project, technical specification group GSM edge radio access network, location services (LCS), Mobile Station (MS) -Serving Mobile Location Center (SMLC) Radio Resource LCS Protocol (RRLP) (release 7).

In addition to the united states Global Positioning System (GPS), other Satellite Positioning Systems (SPS), such as the russian GLONASS system or the proposed european Galileo system, may also be used for the positioning of the mobile station. However, each of these systems operates according to different specifications.

One shortcoming of satellite-based positioning systems is the time it takes to acquire an accurate position fix. Typically, position accuracy is sacrificed to obtain capture speed, or vice versa. I.e. locking with greater accuracy takes more time. Therefore, there is a need for a communication system comprising a Global Navigation Satellite System (GNSS): which can determine the position location of a mobile station based on satellite signals transmitted from two or more satellites, thereby providing further efficiencies and advantages including improved accuracy for position location. There is a need to improve accuracy, for example, during an Emergency Services (ES) call or Value Added Services (VAS) session, while not adversely affecting the acquisition speed or final acquisition time to acquire a position fix for a mobile station.

SUMMARY

Some embodiments of the present invention provide a method of reducing rebids of Measure position request messages between a network and a mobile station in a wireless network, the method comprising: transmitting an RRLP assistance data message; receiving an RRLP assistance data confirmation message; waiting for a predetermined time, wherein the predetermined time is based on a time at which the location data is needed; transmitting an RRLP measure position request message at the predetermined time comprising a network response time and a network accuracy, wherein the network response time comprises a value representing a shortened response time of no more than 4 seconds, wherein the network accuracy comprises a value representing a low accuracy of no less than 100 meters, and wherein the RRLP measure position request message does not include assistance data; and receiving an RRLP measure position response message including the position data at a time before the position data is needed.

Some embodiments of the invention provide a network for reducing rebids of Measure position request messages between the network and a mobile station in a wireless network, the method comprising: a timer to wait for a predetermined time, wherein the predetermined time is based on a time at which the location data is needed; a transmitter to transmit a Measure position request message including a network response time and a network accuracy at the predetermined time; and a receiver for receiving a Measure position response message including the position data at a time before the position data is required. The network is characterized in that the network response time comprises a value representing a shortened response time of not more than 4 seconds. The network is characterized in that the network accuracy includes a value representing a low accuracy of not less than 100 meters. The network is characterized in that the request for measuring the position does not comprise assistance data. The network is characterized in that the Measure position request message comprises an RRLP Measure position request message. The network is characterized in that the Measure position request response message comprises an RRLP Measure position request response message.

Some embodiments of the invention provide a computer-readable product comprising a computer-readable medium, the computer-readable medium comprising: code for causing at least one computer to wait until a predetermined time, wherein the predetermined time is based on a time at which the location data is needed; code for causing at least one computer to transmit a Measure position request message comprising a network response time and a network accuracy at the predetermined time; and code for causing at least one computer to receive a Measure position response message including the position data at a time before the position data is needed. The computer-readable product is characterized in that the network response time comprises a value representing a shortened response time of not more than 4 seconds. The computer readable product is characterized in that the network accuracy comprises a value representing a low accuracy of not less than 100 meters. The computer-readable product is characterized in that the measure position request does not include assistance data. The computer-readable product is characterized in that the computer-readable medium further comprises: code for causing at least one computer to transmit an assistance data message; and code for causing at least one computer to receive an assistance data confirmation message. The computer-readable product is characterized in that the Measure position request message comprises an RRLP Measure position request message. The computer-readable product is characterized in that the Measure position response message comprises an RRLP Measure position response message.

Some embodiments of the present invention provide a method in a network for minimizing rebids between the network and a mobile station in a wireless network, the method comprising: sending a request message, thereby opening a session in the mobile station; determining that an RR message is ready to be sent to the mobile station while the session is open; to avoid interrupting the session due to RR messages; and receiving a response message, thereby closing the session. The method is characterized in that the act of avoiding the interruption of the session comprises: postponing sending the RR message; and sending an RR message after the session is closed. The method is characterized in that the action of avoiding the interruption of the session comprises discarding the RR message. The method is characterized in that the request message comprises an RRLP measure position request message. The method is characterized in that the request message comprises an RRLP assistance data message.

Some embodiments of the present invention provide a network for minimizing rebids between the network and a mobile station in a wireless network, the network comprising: means for sending a request message thereby opening a session in the mobile station; means for determining that an RR message is ready to be sent to the mobile station while the session is open; means for avoiding interruption of the session due to the RR message; and means for receiving a response message thereby closing the session. The method is characterized in that the means for avoiding interrupting the session comprise: means for deferring transmission of the RR message; and means for sending an RR message after the session is closed. The method is characterized in that the means for avoiding breaking the session comprises discarding the RR message. The method is characterized in that the request message comprises an RRLP measure position request message. The method is characterized in that the request message comprises an RRLP assistance data message.

Some embodiments of the present invention provide a network for minimizing rebids between the network and a mobile station in a wireless network, the network comprising: a transmitter for transmitting a request message to thereby open a session in a mobile station; logic for determining that an RR message is ready to be sent to the mobile station while the session is open; logic for avoiding interruption of the session due to the RR message; and a receiver for receiving the response message thereby closing the session. The network is characterized in that the logic for avoiding the dropped session comprises: the timer is used for delaying sending the RR message; wherein the transmitter further sends an RR message after the session is closed. The network is characterized in that the logic for avoiding the dropped session comprises logic for dropping the RR message. The method is characterized in that the request message comprises an RRLP measure position request message. The method is characterized in that the request message comprises an RRLP assistance data message.

Some embodiments of the invention provide a computer-readable product comprising a computer-readable medium, the computer-readable medium comprising: code for causing at least one computer to transmit a request message thereby opening a session in a mobile station; code for causing at least one computer to determine that an RR message is ready to be sent to a mobile station while a session is open; code for causing at least one computer to avoid interrupting the session due to the RR message; and code for causing at least one computer to receive the response message thereby closing the session. The method is characterized in that the code for causing the at least one computer to avoid interrupting the session comprises: code for causing at least one computer to defer sending the RR message; and code for causing at least one computer to send an RR message after the session is closed. The method is characterized in that the code for causing the at least one computer to avoid aborting the session comprises code for causing the at least one computer to drop the RR message. The method is characterized in that the request message comprises an RRLP measure position request message. The method is characterized in that the request message comprises an RRLP assistance data message.

These and other aspects, features and advantages of the invention will become apparent from and elucidated with reference to the embodiment(s) described hereinafter.

Brief Description of Drawings

Embodiments of the invention will now be described, by way of example only, with reference to the accompanying drawings.

FIGS. 1A, 1B, and 1C illustrate various components and interfaces in a wireless network.

Fig. 2 shows a message flow diagram of a typical positioning procedure using an RRLP session.

Fig. 3 shows a pseudo segmentation of the auxiliary data.

Fig. 4 and 5 illustrate stopping positioning based on the MS receiving an additional RR message.

Fig. 6 and 7 illustrate events for turning on and off a GPS engine according to an embodiment of the present invention.

FIG. 8 illustrates a message flow diagram emphasizing early positioning according to an embodiment of the invention.

Fig. 9 and 10 illustrate methods of continuing positioning after receiving an additional RR message according to embodiments of the present invention.

Fig. 11 and 12 illustrate a method of optimally ordering downloaded auxiliary data according to an embodiment of the invention.

Fig. 13 and 14 illustrate a method of sending a Just-in-Time (Just-in-Time) location request according to an embodiment of the present invention.

Fig. 15 and 16 illustrate a method of delaying (or dropping) a new RR message to avoid an interrupted session according to an embodiment of the present invention.

Fig. 17, 18, 19, 20 and 21 illustrate a method of varying an accuracy parameter to balance response time and accuracy in an Emergency Services (ES) call, according to an embodiment of the invention.

Fig. 22 illustrates a message flow diagram for a Value Added Service (VAS) according to an embodiment of the present invention.

Detailed Description

In the following description, reference is made to the accompanying drawings that illustrate several embodiments of the invention. It is to be understood that other embodiments may be utilized and that mechanical, compositional, structural, electrical, and operational changes may be made without departing from the spirit and scope of the present disclosure. The following detailed description is not to be taken in a limiting sense. Furthermore, some portions of the detailed description which follow are presented in terms of procedures, steps, logic blocks, processing, and other symbolic representations of operations on data bits that can be performed on electronic circuitry or on computer memory.

A procedure, computer-executed step, logic block, process, etc., is conceived to be a self-contained sequence of steps or instructions leading to a desired result. The steps are those utilizing physical manipulations of physical quantities. These quantities can take the form of electrical, magnetic, or radio signals capable of being stored, transferred, combined, compared, and otherwise manipulated in electronic circuitry or in a computer system. These signals may sometimes be referred to as bits, values, elements, symbols, characters, terms, numbers, or the like. Each step may be performed by hardware, software, firmware, or a combination thereof. In a hardware implementation, for example, the processing units may be implemented within one or more Application Specific Integrated Circuits (ASICs), Digital Signal Processors (DSPs), digital signal processing Devices (DSPs), Programmable Logic Devices (PLDs), Field Programmable Gate Arrays (FPGAs), processors, controllers, micro-controllers, microprocessors, electronic devices, other apparatus units designed to perform the functions described herein, or a combination thereof.

Reference throughout this specification to "one example," "one feature," "an example," or "a feature" means that a particular feature, structure, or characteristic described in connection with the feature and/or example is included in at least one feature and/or example of claimed subject matter. Thus, the appearances of the phrase "in one example," "an example," "in one feature," or "a feature" in various places throughout this specification are not necessarily all referring to the same feature and/or example. Furthermore, the particular features, structures, or characteristics may be combined in one or more examples and/or features.

An "instruction" as referred to herein relates to an expression representing one or more logical operations. For example, instructions may be "machine-readable" by being interpretable by a machine for executing one or more operations on one or more data objects. However, this is merely an example of instructions and claimed subject matter is not limited in this respect. In another example, instructions referenced herein may relate to encoded commands that may be executed by a processing circuit having a command set that includes the encoded commands. Such instructions may be encoded in the form of a machine language understood by the processing circuitry. Again, these are merely examples of instructions and claimed subject matter is not limited in this respect.

"storage media" as referred to herein relates to physical media capable of maintaining expressions which are perceivable by one or more machines. For example, a storage medium may include one or more storage devices for storing machine-readable instructions and/or information. Such storage devices may include any of a number of media types, including, for example, magnetic, optical, or semiconductor storage media. Such storage devices may also include any type of long term, short term, volatile or non-volatile memory device. However, these are merely examples of a storage medium and claimed subject matter is not limited in these respects. The term "storage medium" does not apply to a vacuum.

Unless specifically stated otherwise, as apparent from the following discussions, it is appreciated that throughout the specification discussions utilizing terms such as "processing," "computing," "calculating," "selecting," "forming," "enabling," "inhibiting," "locating," "terminating," "identifying," "initiating," "detecting," "obtaining," "hosting," "maintaining," "representing," "estimating," "receiving," "transmitting," "determining," and/or the like, refer to actions and/or processes that can be performed by a computing platform, such as a computer or similar electronic computing device, the computing platform manipulates and/or transforms the processors, memory, registers of the computing platform, and/or other information storage, transmission, reception, and/or display devices, as represented by physical electronic and/or magnetic quantities and/or other physical quantities. Such acts and/or processes may be performed by a computing platform, for example, under the control of machine-readable instructions stored in a storage medium. Such machine-readable instructions may comprise, for example, software or firmware stored in a storage medium included as part of a computing platform (e.g., included as part of a processing circuit or external to such a processing circuit). Further, unless specifically stated otherwise, processes described herein with reference to flow diagrams or otherwise may also be executed and/or controlled, in whole or in part, by such a computing platform.

The wireless communication techniques described herein may be incorporated in 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" can be used interchangeably herein. 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, and so forth. A CDMA network may implement one or more Radio Access Technologies (RATs), such as CDMA2000 or wideband CDMA (W-CDMA), to name a few radio technologies. Here, cdma2000 may include technologies implemented in accordance with 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. For example, the WLAN may include an IEEE 802.11x network, and the WPAN may include a bluetooth network, IEEE 802.15 x. The wireless communication implementations described herein may also be used with any combination of WWAN, WLAN and/or WPAN.

The device and/or system may estimate a location of the device based at least in part on signals received from the satellites. In particular, such devices and/or systems may obtain "pseudorange" measurements that include approximations of distances between associated satellites and a navigation satellite receiver. In a particular example, such pseudoranges may be determined at a receiver capable of processing signals from one or more satellites as part of a Satellite Positioning System (SPS). Such SPS's may include, for example, Global Positioning System (GPS), Galileo, Glonass, to name just a few, or any SPS developed in the future. To determine its position, a satellite navigation receiver may obtain pseudorange measurements to three or more satellites and their positions at time of transmission. Knowing the orbital parameters of the satellites, the positions can be calculated for any point in time. The pseudorange measurements may then be determined based, at least in part, on the time a signal travels from the satellite to the receiver multiplied by the speed of light. While the techniques described herein may be provided as an implementation of positioning in a GPS and/or Galileo type SPS as a specific illustration, it should be understood that these techniques may also be applied to other types of SPS, and that claimed subject matter is not limited in this respect.

The techniques described herein may be used in connection with any of several SPS, including, for example, the aforementioned SPS. Further, these techniques may be used in connection with positioning systems that utilize pseudolites or a combination of satellites and pseudolites. Pseudolites may comprise ground-based transmitters that broadcast a pseudorandom noise (PRN) code or other ranging code (e.g., similar to a GPS or CDMA cellular signal) modulated on an L-band (or other frequency) carrier signal, which may be synchronized with GPS time. Such a transmitter may be assigned a unique PRN code to permit identification by a remote receiver. Pseudolites may be useful in situations where SPS signals from an orbiting satellite might be unavailable, such as in tunnels, mines, buildings, urban canyons or other enclosed areas. Another implementation of pseudolites is known as radio beacons. The term "satellite" as used herein is intended to include pseudolites, equivalents of pseudolites, and possibly others. The term "SPS signals" as used herein is intended to include SPS-like signals from pseudolites or equivalents of pseudolites.

As used herein, a handheld mobile device or Mobile Station (MS) refers to a device whose location or position may change from time to time. Changes in positioning and/or location may include changes in direction, distance, orientation, etc., as a few examples. In particular examples, a mobile station may include a cellular telephone, a wireless communication device, user equipment, a laptop computer, other Personal Communication System (PCS) devices, and/or other portable communication devices. The mobile station may also include a processor and/or computing platform adapted to perform functions controlled by machine-readable instructions.

The present application is directed to the following applications, each filed concurrently with the present application and each incorporated herein in its entirety: "Optimized Ordering of Assistance Data in a Mobile radio network" by Kirk Allan Burroughs (attorney docket No. 072346); "improved GPS Domain For Emergency Calls in Mobile radio networks" by Thomas Rowland (attorney docket No. 080114); and "Dynamic measurement Position Request Processing in mobile Radio Network" by Thomas Rowland (attorney docket No. 080116).

FIGS. 1A, 1B, and 1C illustrate various components and interfaces in a wireless network. For simplicity, the following description uses general terminology used in wireless networks or specific terminology used with reference to a particular standard, but the techniques described in this disclosure may be applicable to a number of different wireless network standards. For example, such wireless networks include Code Division Multiple Access (CDMA) systems, which are high capacity digital wireless technologies developed and commercially exploited by QUALCOMM (high-pass) corporation. Another wireless network includes global system for mobile communications (GSM), which uses alternative digital wireless technologies. Yet another wireless network includes Universal Mobile Telephone Service (UMTS), which is the next generation of high capacity digital radio technology.

Fig. 1A includes a mobile station (MS 10), a base station subsystem (BSS 20) including a base transceiver station (BTS 22) and a base station controller (BSC 24), a mobile switching center (MSC 30), a Public Switched Telephone Network (PSTN), and a Serving Mobile Location Center (SMLC). The MS10 is any mobile wireless communication device, such as a cellular telephone having a baseband modem for communicating with one or more base stations. The MS referred to in this disclosure includes a GPS receiver or equivalent receiver for providing location capability. The term GPS is used below to refer in a general sense to a satellite or pseudolite system. The MS10 and BTS22 are referred to as U_mCommunicate wirelessly over the RF air interface of the interface. One or more MSs 10 may communicate with BTS22 or BSS20 simultaneously. The BTS22 built into the BSS20 may communicate to the BSC 24 via the Abis interface. One BSC 24 may support several BTSs 22 in the deployed network. Here, when U from the network (downlink) and from the MS10 (uplink) are involved_mAir interface messages, these messages may also be considered to be communicated using the BTS22, or equivalently, the BSS 20. L is_bThe interface couples BSC 24 with SMLC 50. When L is involved_bWhen interfacing downlink and uplink messages, these messages may also be considered to be communicated using the BSC 24 or, equivalently, the BSS 20. AOne or more BSCs 24 and/or BSSs 20 may be coupled to MSC 30 using an a interface. The MSC 30 connects the switched circuit from the PSTN 40 to the MS10 to provide voice calls to the public network. Other network elements or network components may be connected to the BSS20, the MSC 30, and the PSTN 40 to provide other services.

For example, the SMLC50 may be coupled to a network to provide location services and is shown as passing through L_bThe interface is connected to the BSC 24. SMLC50 may also be via MSC 30 and L_sThe interface is connected to a wireless network. The SMLC50 provides overall coordination for locating the mobile station and may also calculate the final estimated position and the achieved accuracy of the estimate. SMLC50 is used herein generically to refer to a location server, which is also referred to as a Position Determination Entity (PDE) in CDMA networks, a Serving Mobile Location Center (SMLC) in GSM networks, and a standalone (a-GPS) SMLC (sas) in WCDMA cellular networks.

A location server is a system resource (e.g., a server) typically within a wireless network and operates in conjunction with one or more GPS reference receivers capable of exchanging GPS-related information with the MS. In an MS-assisted a-GPS session, the location server sends GPS assistance data to the MS to enhance the signal acquisition process. The MS may return pseudorange measurements to a location server, which is then able to compute the position of the MS. Alternatively, in an MS-based A-GPS session, the MS sends back the computed position fix to the position server.

FIG. 1B shows U_mAnd L_bA hierarchical model of an interface. The layers in the MS10 (target MS) include a first layer called the physical layer, layer 1 or L1, a second layer called L2(LAPDm), a third layer called the Radio Resource (RR) layer, modeled after the GSM 04.08 specification, and finally an application layer. In this case, the application layer is the Radio Resource Location Protocol (RRLP) defined in the GSM 04.31 and GSM 04.35 recommendations. BSS20 (shown as BSC 24) has a corresponding hierarchical model including L1, L2(LAPD), and RR layers, and the RRLP message passes through BSS 20. BSS20 passes L_bThe interface relays the underlying layer to the SMLC50 as needed. These layers include MTP, SCCPBS with SMLC50MTP, SCCP BSSLAP-LE and BSSLAP layers corresponding to the SLAP-LE and BSSLAP layers. For additional information on BSSAP-LE and BSSLAP interfaces, see GSM 09.21 and GSM 08.71 recommendations.

Messages passed from network element to network element may pass through a number of different interfaces and corresponding protocols. For example, a message delivered from the location server SMLC50 to the BSS20 and then to the MS10 will be the first message at L_bIs communicated over the interface, is communicated over the Abis interface as a possible further message, and is communicated over the U as a final message_mIs communicated over the interface. Generally, in this disclosure, messages will be referred to by their application layer and air interface names for simplicity. For example, a request from the location server SMLC50 destined for the MS10 may be made using the air interface U_mThe application layer name, RRLP measure position request. Accordingly, for clarity, BSS20 and SMLC50 may be collectively referred to as network 70, which may include BTS22, BSC 24, and SMLC50, or may include BSS20 and SMLC 50.

Fig. 1C shows a message flow diagram for a normal RRLP session. At time a, SMLC50 is at L_bA request message 80 is sent over the interface to BSS 20. BSS20 repackages this request and treats it as being in downlink U_mThe RRLP request 85 transmitted over the air interface is forwarded to the MS 10. The MS10 starts an RRLP session and eventually on the uplink U_mReplies over the air interface with an RRLP response message 90. BSS20 repackages the reply again and passes through L_bThe interface forwards it to the SMLC50 in a response message 95, which the SMLC50 receives at time b. Hereinafter, such requests and responses to and from the SMLC50 will be referred to as RRLP requests and RRLP responses.

The 3GPP RRLP application layer currently supports five messages. The first message is an RRLP measure position request message used on the downlink. The network 70 uses this message to request a location measurement or location estimate from the MS 10. This message includes instructions for the MS10 and may also include assistance data for the MS 10. The assistance data is described in additional detail below. The second message is an RRLP measure position response message used on the uplink and is complementary to the RRLP measure position request message. The MS10 uses this message to respond to the network 70 with position estimation information and other position related information. The RRLP measure position request message and the RRLP measure position response message operate together to start and terminate an RRLP session.

The third and fourth messages also operate together to start and terminate an RRLP session. The third message is another downlink message, referred to as an RRLP assistance data message, which is used by the network 70 to send assistance data to the MS 10. The assistance data optionally includes enhanced observed time difference (E-OTD) reference BTS information (e.g., BTS signaling and location information) and E-OTD measurement information for up to 8 additional BTSs. The fourth message is an RRLP assistance data acknowledgement (Ack) message used on the uplink. The RRLP assistance data confirmation message is used only by the MS10 to confirm receipt of the RRLP assistance data message to the network 70. The fifth message is an atypical message called an RRLP protocol error that can be used on either the downlink or uplink to report errors in the protocol.

Fig. 2 shows a message flow diagram of a typical positioning procedure using an RRLP session. The MS10 and the network 70 may be considered a client-server model, in which the MS10 acts as a client and the network 70 acts as a server. The RRLP session begins with a request from the network 70 and typically ends with a response from the MS 10. At time a, the positioning procedure begins with the network 70 communicating an RRLP assistance data message 110 with the MS 10. That is, the network 70 sends an RRLP assistance data message 110 to the MS10, and the MS10 begins a new RRLP session upon receiving the RRLP assistance data message 110. Normally, as shown at time b, the MS10 completes the RRLP session with an acknowledgement response called an RRLP assistance data acknowledgement message 112.

At time c, the network 70 sends an RRLP measure position request message 120, which includes positioning instructions and optionally assistance data. The positioning instruction from the network 70 includes a maximum response time (NW response) set by the Network (NW) and a minimum accuracy (NW accuracy) also set by the Network (NW). In response to receiving the RRLP measure position request message 120, the known mobile station turns on its GPS engine. GPS is commonly used to refer to a positioning system using Satellite Vehicles (SVs) and/or pseudolites. The engine may also be used generally as hardware and/or firmware and/or software to operate on data. The MS10 then determines one or more position fixes that each have an estimated uncertainty.

The positioning process stops once the estimated uncertainty is less than or equal to the minimum network accuracy (NW accuracy) signaled by the network 70, or once the MS10 has calculated a lock on for as long as the network response time (NW response) parameter allows. The MS10 reports the calculated fix in an RRLP measure position response message 122, as shown at time d, and also turns off the GPS engine. The time difference between time references c and d may be substantial (e.g., from 45 seconds to several minutes). One goal in localization is to minimize this acquisition time. Another object is to reduce the uncertainty of the provided locking.

Fig. 3 shows a pseudo segmentation of the auxiliary data. The assistance data may include position data about one or more Satellite Vehicles (SVs). Since assistance data typically contains information about 8 to 12 or more satellites, the assistance data is divided into a plurality of pseudo-segmented assistance data message blocks, where each block contains information about one, two, three or four satellites. In the illustrated example, the auxiliary data is segmented into three pseudo segments. The first two blocks may contain information about three or four satellites and the last block may contain information about one, two or three satellites, for the illustrated example amounting to seven to eleven satellites.

The first piece of assistance data is communicated from the network 70 to the MS10 at time a in a first RRLP assistance data message 140. Upon receipt, the first RRPL session begins, but terminates quickly when the MS10 sends an RRLP assistance data confirm message 142 to the network 70 at time b.

The second block of assistance data is communicated from the network 70 to the MS10 at time c in a second RRLP assistance data message 144. Upon receipt, the second RRPL session begins. In this example, at time d, the MS10 does not have time to deliver an acknowledgement message before it receives the second RR message (referred to herein as the additional RR message 130) that terminates the RRLP session created by message 144. The additional RR message may be any of several different RR messages. For example, a higher priority RR message, such as a handoff message, may have been transmitted to the MS 10.

If either the MS10 receives a portion of the downlink RRLP message or there is no downlink RRLP message, the session is said to be preempted. Preemption occurs when a message is placed in an outgoing queue of the network for transmission. In some cases, the remainder of the message that has not been transmitted is cleared from the queue by higher priority messages before the downlink RRLP message can be fully transmitted. In these cases, the MS10 may have received some but not the entire downlink RRLP message. In other cases, the downlink RRLP message is cleared even before the first bit of the message is transmitted over the air interface. In these cases, the session is also considered preempted, however, the MS10 does not know the existence of the session. Preemption often occurs when the downlink RRLP message is long or when there are longer messages ahead of it in the same downlink queue (i.e., other messages are scheduled for earlier transmission times).

On the other hand, if the MS10 receives the entire downlink RRLP message but has not yet completely sent a response, such as an RRLP assistance data acknowledgement message, then the session is considered to be interrupted. Interruptions often occur when the MS10 spends a relatively long period of time responding to downlink RRLP messages.

In the case of preemption and interruption, the existing session in the MS10 and/or the network 70 is terminated. One goal is for the MS10 to respond quickly to downlink RRLP messages, thereby minimizing dropped sessions. Another objective is to have the network send shorter downlink RRLP messages, thereby keeping the queues less full and minimizing pre-emption sessions. The purpose of the pseudo-segmentation is that the second target-having shorter downlink RRLP messages thereby reduces the chance of pre-empting the session, but not addressing the first target-responds quickly to the downlink messages as described below with respect to the processing associated with the RRLP measure position request message.

In the following, the terms interrupt (noun), interrupt (verb), or interrupt (passive) will be used to refer to the termination of a session caused by or due to an interrupted session receiving an additional RR message or the preemption in a downlink queue of a higher priority downlink message.

To recover from the interrupted session, the network 70 transmits a rebid message. The recall message is a subsequent transmission of a message previously placed in the downlink queue. In the example shown at time e, the second block of assistance data is included in a recall RRLP assistance data message 148, which message 148 begins a third RRLP session at the MS 10. The MS10 acknowledges receipt to the network 70 with another RRLP assistance data acknowledgement message 150 at time f.

The final block of assistance data is transmitted from the network 70 to the MS10 at time g in an RRLP measure position request message 120, which RRLP measure position request message 120 is received by the MS10 and in this example starts the fourth session. The MS10 is now instructed to start the position fix, which may take tens of seconds to minutes. During the period from the receipt of the instruction to the transmission of the response, the session is prone to suffer session interruption due to the additional RR messages. In this example, the final session is not interrupted, but rather the MS10 responds with an RRLP measure position response message 122 at time h.

Fig. 4 and 5 illustrate stopping the positioning based on the MS10 receiving the additional RR message. In fig. 4, at time a, the network 70 sends an RRLP assistance data message 110 to the MS10, and then at time b, the MS10 replies with an RRLP assistance data confirmation message 112. The network 70 and the MS10 may repeat this message exchange several times to provide almost all assistance data to the MS10 before starting the GPS engine. At time c, the network 70 sends an RRLP measure position request message 120 with the final block of assistance data to the MS 10. At this point, the MS10 starts its GPS engine and starts the position fix.

At time d, the network 70 sends an additional RR message 130 to the MS10 (i.e., a message that the MS did not expect to receive because it is in an ongoing session). This additional RR message 130 occurs before the MS10 is able to convey the reply message, causing the MS10 to abort the current session initiated by the RRLP measure position request message 120. As part of interrupting the session, the MS10 turns off the GPS engine, terminates the positioning process, responds to the additional RR message 130, and waits for a subsequent request from the network 70. After a short delay Δ t, at time e (where Δ t — e-d), the network 70 transmits a recall 120A to the RRLP to measure position request message that causes the MS10 to restart its GPS engine and start positioning again. This process of sending a rebid 120A of the message following the interruption by the additional RR message 130 may occur several times before the MS10 is able to determine its location within the preset network response time and accuracy parameters. At time f, the MS10 reports the position fix to the network 70 in an RRPL measure position response message 122.

Fig. 5 illustrates this message exchange in the form of a state diagram. When the MS10 receives the RRLP Measure position request message 120, the MS10 enters state 200, which state 200 turns on the GPS engine and starts positioning. In normal uninterrupted operation, the MS determines the location 220 and reports the location to the network by entering state 230, and state 230 sends an RRPL measure location response message 122. When lock cannot be determined within the preset network response time (e.g., when a response time timeout occurs), the MS10 may exit state 200 and enter state 230 where the MS10 replies with an RRPL measured location response message 122 containing a lock with worse accuracy than requested by the network.

The state diagram shows other conditions that may occur. For example, when the MS10 receives the additional RR message 130, it will exit state 200 and enter state 210. In state 210, the MS10 turns off the GPS engine and stops position location. When the MS10 receives the recall RRLP measure position request message 120A, it exits state 210 and re-enters state 200. Finally, the MS10 either locates or times out 220 as usual and enters state 230 to respond with an RRPL measure position response message 122.

In the positioning process described above, the MS10 waits for the RRLP measure position request message 120 before turning on its GPS engine and turns off its GPS engine when it receives the additional RR message 130, thereby minimizing the time duration for the GPS engine to run. By turning on the GPS engine in response to receiving the RRLP measure position request message 120, the MS10 is aware that the network 70 requires a position fix. In any other scenario, there is no guarantee that the network 70 will request a position fix from the MS 10. Thus, by not being turned on until this point, the MS10 conserves battery power. The MS10 may also conserve battery power by shutting down the GPS engine once the RRLP session is over (e.g., as a result of an interruption or reporting a position fix).

In accordance with some embodiments of the present invention, advantages may be realized by not following this known procedure, but instead turning on the GPS engine in anticipation of the RRLP measure position request message 120 being received. Further, advantages may be realized by not shutting down the GPS engine after the RRLP session is over. At the expense of battery power, the GPS engine may be turned on early (i.e., before receiving the RRLP measure position request message 120) and the positioning process may continue even if the RRLP session terminates.

Fig. 6 and 7 illustrate events for turning on and off a GPS engine according to an embodiment of the present invention. The state diagram of fig. 6 shows two states: state 800, where the GPS engine is not running; and a state 810 in which the GPS engine has been turned on and the positioning process has begun. Several user-side and network-side triggering events may occur that turn on the GPS engine early in anticipation of an RRLP measure position request message 120 being received in the future. The triggering event occurs after the start of the runtime operation. That is, the trigger event does not simply turn on the mobile station, but rather causes the mobile station to enter run-time operation. Some devices run the GPS engine at all times, so there is no triggering event to turn on the GPS engine. The triggering event is not a user action for specifically turning on the GPS positioning function of the mobile station. A triggering event is an event that does not normally turn on the GPS engine. Also, the triggering event occurs before receiving an RRLP measure position request message, which is a message that typically turns on the GPS engine.

First, at 820, if the MS10 detects a triggering event that an Emergency Services (ES) call has been initiated, the MS10 may transition from state 800 to state 810. Another user-side initiated transition may occur if MS10 receives a message from a mobile station application (MSApp) indicating that a position fix is required. A network-side event may also initiate a transition from state 800 to state 810. For example, at 840, if the MS10 receives a triggering event for a new RRLP assistance data message, the MS10 may transition from state 800 to state 810. At 850, if the MS10 receives a triggering event for a Value Added Service (VAS) message, the MS10 may transition from state 800 to state 810. For completeness, the process of transitioning states as known is illustrated by receiving the RRLP measure position request message 120 at 860.

In addition to the early turn on described with reference to FIG. 6, turning off the GPS engine may be advantageously postponed as shown in FIG. 7, which also includes two states. In state 900, the GPS engine is running (i.e., due to one of the events described above). In state 910, the GPS engine is turned off. Several events may trigger a transition from state 900 to state 910 to turn off the GPS engine. For example, a location may be deduced, or a timeout may occur. At 920, a transition occurs as a result of the newly sent RRPL measure position response message 122 when there is no further significant need for the engine to continue running, such as the MS APP waiting for a better position fix. The transition may also occur when a position fix has just been reported to the MS APP and the MS10 did not expect an RRLP measure position request message 120 and did not expect an RRPL measure position response message 122 to be sent.

An anomalous situation may also lead to a transition. For example, at 940, if the MS10 has expected the RRLP Measure position request message 120 (e.g., due to event 820 or 840 described above), but has not received the message within a predetermined period of time (e.g., 45, 60, or 90 seconds or a value selected from a time range of 30-60, 30-90, 30-120, 30-180, 30-240, 60-90, 60-120, 60-180, 60-240, 90-120, 90-180, 90-240, 120-180, 120-240, etc., as will be understood by those skilled in the art), the MS10 may turn off its GPS engine. Similar to at 940, if the GPS engine has been running for too long (e.g., 120 or 180 seconds), the MS10 may time out and shut down the GPS engine to conserve battery power.

FIG. 8 illustrates a message flow diagram emphasizing early positioning according to an embodiment of the invention. One goal is for the MS10 to turn on the GPS engine as soon as the RRLP measure position request message 120 from the network 70 is expected or predicted to come in the future. At time a, the MS10 identifies the dialed digits of the emergency service call (e.g., "911" in the united states, "112" in europe, or "119" in japan). Once the call is identified as an emergency services call, the MS10 may begin positioning by turning on its GPS engine in anticipation of a need for a position fix for the MS 10.

At time b, the network 70 sends an RRLP assistance data message 110 to the MS 10. In response, at time c, the MS10 replies with an RRLP assistance data confirmation message 112. This process of sending messages 110 and 112 may be repeated until sufficient assistance data has been transferred by network 70. Finally, at time d, the network 70 sends an RRLP measure position request message 120 to the MS 10. The MS10 continues to determine its location. Next, at time e, the MS10 replies to the network 70 with an RRLP measure position response message 122 containing its determined position.

Fig. 9 and 10 illustrate methods of continuing positioning after receiving the additional RR message 130 according to embodiments of the present invention. Another goal is to continue operating the GPS engine throughout the secondary abnormal event. In fig. 9, the additional RR message 130 interrupts the current measurement session, but the MS10 continues the location process and does not interrupt its GPS engine. At time a, the MS10 receives an RRLP assistance data message 110 from the network 70. In response, at time b, the MS10 replies with an RRLP assistance data confirm message 112. Again, this process of sending messages 110 and 112 may be repeated until sufficient assistance data has been transmitted by network 70.

At time c, the network 70 sends an RRLP measure position request message 120 to the MS 10. At this point, the GPS engine is already running based on the MS10 recognizing an emergency or other triggering event. At time d, the network 70 breaks the RRLP session beginning at time c before the network 70 receives the reply. Known mobile stations terminate RRLP sessions and also turn off the GPS engine. Here, the MS10 leaves the GPS engine uninterrupted to allow it to continue the positioning process.

Finally, at time e, the network 70 resends the RRLP measure position request message 120A to the MS10 during the recall process. Again, the MS10 does not turn the GPS engine back on, but continues the positioning process. As described above, the process of interrupting and rebeaming may be repeated. Next, at time f, the MS10 replies to the network 70 with an RRLP measure position response message 122 containing its determined position.

Fig. 10 shows a state diagram. When a triggering event occurs, the MS10 enters state 300. The triggering event includes receiving an RRLP measure position request message 120, receiving an RRLP assistance data message 110, identifying initiation of an emergency services call, etc. In state 300, the MS10 continues positioning with the GPS engine already running or begins positioning by turning on the GPS engine if the GPS engine has not been turned on.

Normally, the MS10 exits state 300 (shown as transition 310) and enters state 320 either when a location is determined or when a timeout occurs. For example, a timeout may occur when the MS10 determines that the network 70 is expecting measurements to be made within a small predetermined amount of time. In some cases, the MS10 exits state 300 and enters state 330 when the MS10 receives an additional RR message 130 that interrupts the current RRLP session before the MS10 can send its response.

In state 330, the MS10 discontinues the current RRLP session, but continues with the position fix. Upon receiving the recall RRLP measure position request message 120A, the MS10 enters state 340 but continues the location procedure again. Once the MS10 determines the location or a timeout occurs (shown as transition 340), the MS10 exits state 340 and enters state 320. In state 320, the MS10 sends its RRLP measure position response message 320 to the network 70.

Fig. 11 and 12 illustrate a method of optimally ordering downloaded auxiliary data according to an embodiment of the invention. The assistance data may be sent in one or more (pseudo-segmented) RRLP assistance data messages 110 and/or in an RRLP measure position request message 120. Optimally ordering the communication of assistance data from the network 70 to the MS10 enables the MS10 to advantageously begin the positioning process early and actively use segmentation of the assistance data before being instructed by the RRLP measure position request message 120.

Fig. 11 shows an optimal ordering of the segmented auxiliary data 400. The first segment includes reference information 410 including satellite time and a coarse MS location 420. The first and remaining segments include satellite vehicle position information (including almanac and ephemeris data) 430. The satellite vehicle position information 430 is ordered from first best 440, to second best 450, and on to last best 460. Not all available satellites must be placed in this optimally ordered assistance data list.

The optimal ordering of the satellites may take into account one or more factors to provide the MS10 with the set of satellites that are most likely to be visible and most likely to assist the MS10 in quickly determining its location. For example, knowledge of the coarse MS location may be used to find satellite locations empirically indicated as visible to mobile stations having similar coarse MS locations. The network 70 may look for satellites that will be in a region of space that observations or experiments indicate is available for mobile stations with similar or the same coarse MS location.

Further, knowledge of the coarse MS location may be used to determine general characteristics of the environment. This environmental characteristic may be used to identify the best satellite to allow the MS10 to determine its location. The coarse MS location may identify the MS10 as being located, for example, in a rural landscape (e.g., in a flat rural environment), a mountainous landscape (e.g., in a north-south oriented valley or along the west of a mountain), or an urban landscape (e.g., in a dense downtown area with tall buildings). If the coarse MS position indicates that the MS10 is most likely to have an unobstructed view of the sky, the network 70 may first provide satellite position information for a set of orthogonal or pseudo-orthogonal satellites, e.g., three satellites that are 120 deg. apart from each other and closest to 45 deg. off the horizon. Any two of the three satellites may be oriented substantially orthogonally with respect to the mobile station. That is, a first line between the first satellite to the mobile station forms a right angle (orthogonal) or an angle between 60 ° and 120 ° (approximately orthogonally oriented) with a second line between the second satellite to the mobile station. If the coarse MS location indicates that the MS10 may not be able to see satellites located in a particular spatial region (e.g., if the east sky is blocked by a mountain), the location information for these satellites may be lower in the optimal satellite list (or even removed from the list entirely).

In addition to the reference information 410, the first segment of assistance data may also include information about one or both satellites, as provided by the allowable message length. The first segment includes satellite position information 440 that is optimal for the MS 10. A second segment of assistance data comprises satellite position information 450 for two, three or four sub-optimal satellites. Each subsequent segment of assistance data includes satellite position information for equally or less optimal satellites until the end-optimal set 460 is reached.

Fig. 12 shows a flow chart for sorting and transmitting segments of assistance data. At step 500, the network 70 sorts the satellite lists from first best to last best for the MS10 to produce a sorted list, both of which may be stored in memory within the network 70. The ordering is specific to each MS 10. For example, the ordering may depend on the coarse MS location. At step 510, the network 70 transmits a first segment RRLP assistance data message 110 including reference information (i.e., reference time and coarse MS location) and satellite location information for the first best satellite.

At step 520, the network 70 determines whether it is time to send the RRLP measure position request message 120 at this time, for example, using a controller or controller logic within the network 70. If sufficient assistance data has been sent to the MS10, the network 70 may determine that it is time to send the RRLP Measure position request message 120. If the MS10 has satellite position information for at least a predetermined number of satellites (e.g., 4-14 satellites), the network 70 may determine that the MS10 has a sufficient amount of assistance data. Alternatively, if the predetermined number of satellites is not reached and no more satellite information is available to send in the assistance data message, the network may either transmit an RRLP measure position request message (with or without the final segment of assistance data) or may set a timer so that the RRLP measure position request message is sent to receive the RRLP measure position response message instantaneously. Alternatively, if the time remaining before the network 70 requires a position fix is less than a predetermined amount of time, the network 70 may determine that the MS10 already has a sufficient amount of assistance data. In this case, if a timeout has occurred, the network 70 will determine that it is time to send the RRLP measure position request message 120. Alternatively, if all assistance data has been previously sent, the network 70 may determine that it is time to send the RRLP measure position request message 120 at this time.

If it is not time to send the RRLP measure position request message 120 at this time, the network 70 may proceed to step 530. If it is time to send the RRLP measure position request message 120 at this time, the network 70 may proceed to step 540. At step 530, the network 70 sends the next segment RRLP assistance data message 110 including location information for the suboptimal group of satellites, and then returns to step 520. This loop between steps 520 and 530 may continue multiple times. At step 540, the network 70 sends an RRLP measure position request message 120. The RRLP measure position request message 120 may include a final segment of assistance data. Alternatively, the RRLP measure position request message 120 may avoid any assistance data, as described in detail below.

Fig. 13 and 14 illustrate a method of sending an instant location request according to an embodiment of the present invention.

In fig. 13, at time a, the network 70 starts an RRLP session by sending an RRLP message, such as the RRLP measure position request message 120. This scenario assumes that the network 70 successfully sends one or more RRLP assistance data messages 110 to the MS10, or that the MS10 already has assistance data in its memory. In the illustrated example, the network 70 requires a location fix from the MS10 in approximately 35 seconds. At time b, the RRLP session is interrupted by some other RR message 131.

In some cases, the RRLP message 120 shown at time a may still be in an outgoing queue of the network 70, and thus the MS10 has not received an RRLP message and has not yet started an RRLP session. In this case, other RR message 131 preempts RRLP message 120 by removing RRLP message 120 from the queue before it can be successfully and completely transmitted out of the queue. The GPS engine is already running because the MS10 previously received a triggering event, such as a first RRLP assistance data message (not shown). During each subsequent message, the GPS engine continues the uninterrupted position location process.

Network 70 leaves only a minimum value for time (e.g., approximately 4 seconds left) before determining that a position fix is required at time c. The network 70 sends an RRLP measure position request message 120B to the MS 10. This message 120B is sent at a time (time c) so that the response will be received immediately (at time d). In some embodiments, RRLP measure position request message 120B is sent along with NW response time and NW accuracy parameters, but not with assistance data. The RRLP measure position request message 120 may include a short timeout during which the MS10 must return a position fix (e.g., NW response time represents 2 or 4 seconds), and may contain a low value of uncertainty (NW accuracy indicates high accuracy, e.g., approximately 10 meters). Alternatively, the RRLP measure position request message 120 may include a set of position accuracy parameters to allow for large position uncertainty (NW accuracy indicates low accuracy, e.g., approximately 250 meters). At time d, the network 70 instantaneously receives the RRLP measure position response message 122 from the MS10 when approximately 0 seconds or nearly 0 seconds remain.

This instant procedure can be invoked because a recall is required due to an earlier interrupted RRLP session. In some cases, the interrupted RRLP session must be the session started by the earlier RRLP measure position request message 120 (as shown). In some cases, the interrupted RRLP session must be the session started by the RRLP assistance data message 110. In some cases, the interrupted RRLP session may be a session started either by the earlier RRLP measure position request message 120 or by the RRLP assistance data message 110.

Fig. 14 illustrates a process for instant location request and response in the network 70. At step 600, the network 70 determines the future time at which the RRLP measure position response message 122 is needed. At step 610, the network 70 sets a timer, scheduler, etc., and waits until just before the positioning data is needed (e.g., 4 seconds ago). Here during the waiting time both after the last RRLP message and before the instant RRLP measure position request message 120, the network may send other RR messages and not interrupt the mobile station's location process.

At step 620, the network 70 sends an RRLP measure position request message 120. This message 120 is sent without accompanying assistance data at a time that allows the MS10 sufficient time to respond. At step 630, the network 70 receives the RRLP measure position response message 122 just before the desired position.

As mentioned above, this instant procedure may be implemented for all RRLP measure position request messages 120 being transmitted by the network 70. Waiting to send the RRLP measure position request message 120 until just before a position fix is needed (e.g., if a rebid is experienced) helps to reduce the occurrence of dropped sessions and conserve channel bandwidth. Alternatively, this process may be implemented if one or more interruptions and/or preemptions have occurred within the present communication with the MS 10. Alternatively, this process may be implemented for a mobile station with a similar coarse MS location if one or more interruptions or preemptions have occurred in communications with other mobile stations in this cell.

Fig. 15 illustrates a method of minimizing rebids between the network 70 and the MS10 in the wireless network. At time a, the network 10 sends an RRLP request message 100, thereby opening a session. The RRLP request message 100 may be either an RRLP assistance data message 110 or an RRLP measure position request message 120. At time b, before the network 10 has received a response from the MS10, the network 70 determines that a new RR message is ready to be sent from the network 70 to the MS10 while the RRLP session is still open. In known systems, the network 70 immediately sends this new RR message, thereby interrupting the current RRLP session. According to an embodiment of the invention, the network 70 delays (if allowed) sending the new RR message to avoid the current RRLP session being interrupted. That is, to avoid aborting the RRLP session, the network 70 holds the new RR message until the RRLP response/acknowledgement message 102 is received, thereby causing the RRLP session to be closed normally. Based on the particular new RR message, the network 70 may either defer sending the new RR message or discard the RR message altogether. At time c, the network 70 receives and identifies the RRLP response/acknowledgement message 102. Shortly thereafter, at time d, if the new RR message is not dropped, the network 70 sends the new RR message after the RRLP session closes, thereby avoiding interruption of the RRLP session.

In fig. 16, the network 70 sends an RRLP request message at step 650. At step 660, before the RRLP session closes, the network 70 determines that it has a new RR message ready to be sent to the MS 10. At step 670, the network 70 determines whether it is permissible to delay (or drop) the sending of the new RR message. If not, the network 70 sends a new RR message at step 690, thereby inevitably disrupting the current RRLP session. At step 680, network 70 waits and then RRLP response/acknowledgement message 102. If the new RR message is delayed, processing continues to step 690 before processing is completed. If the new RR message has been discarded, no new RR message remains to be sent and processing is complete.

Fig. 17 shows an example of call flow processing for an Emergency Services (ES) call that uses increased accuracy when time is available. At time a (t ═ 0), the MS10 identifies the ES call. In response to identifying the ES call, the MS10 turns on the GPS engine. The MS10 may set the activity timer to a large value (e.g., Act _ timer) for 40 seconds. One purpose of the activity timer is to monitor activity (or inactivity) between the network 70 and the MS 10. If there is no activity during this time, the activity timer will time out and the GPS engine will be shut down.

At time b, the network 70 sends a first RRLP assistance data message 140. This first message 140 contains reference information 410 (satellite time and coarse MS location 420 from fig. 11). It also contains satellite position information about the satellites that are most optimal for the MS 10. At time c, the MS10 replies with an RRLP assistance data confirmation message 142. At time d and time e, the process of communicating assistance data message 144 and acknowledgement message 146 may be repeated one or more times to transmit additional assistance data (satellite position information) for the sub-optimal satellites for MS 10.

Next, the network 70 prepares an RRLP measure position request message 120. The RRLP measure position request message 120 may contain a value for a network response time (NW response time) parameter. This NW response time parameter may be set to indicate an intermediate response time (e.g., a value of 4 corresponds to 16 seconds). The message 120 may also contain a network accuracy (NW accuracy) parameter. This NW accuracy parameter may be set to indicate moderate accuracy or uncertainty (e.g., a value of 19 corresponds to 51.2 meters). This parameter, as well as other distance or uncertainty parameters or ranges described herein as having particular values, are provided by way of example only. Other values may be used. As will be understood by those skilled in the art, a value of 51.2 meters or 245.5 meters may be, for example, a value ranging from 40 to 60 meters, 30 to 70 meters, 40 to 100 meters, 100 to 150 meters, 100 to 250 meters, 100 to 300 meters, 100 to 400 meters, etc.

At time f, the network 70 sends an RRLP measure position request message 120. In some cases, the last set of assistance data is included in this message 120. In other cases, the last set of assistance data is included in a previous message, which is the RRLP assistance data message 144.

To improve accuracy, the MS10 may use an accuracy value that represents no or little uncertainty. For example, the Act _ Accuracy parameter may be set to a value of 0, which represents an uncertainty of 0 meters (highest Accuracy value). Alternatively, the Act _ Accuracy parameter may be set to a value of 1, 2, 3, or 4 to represent an uncertainty of 1.0, 2.1, 3.3, or 4.6 meters, respectively. Other values representing no or little uncertainty may also be used.

In some cases where the MS10 drives this Accuracy improvement procedure, the MS10 advantageously sets the Act _ Accuracy parameter independent of the NW Accuracy parameter sent by the network 70. In other situations where the network 70 drives the accuracy improvement procedure, the network 70 advantageously and temporarily overrides its standard network accuracy (e.g., 51.2 meters) and sets its parameters to be later sent in the RRLP measure position request message 120 to an accuracy value representing no or little uncertainty.

As shown, after time f, for example, if the remaining time on the current active timer is less than the network preset response time, the MS10 resets its active timer from the current countdown (e.g., 20 seconds) to a value that matches the network response time (Act _ timer — NW response time). In this way, the MS10 will not prematurely turn off the GPS engine before determining that the positioning measurement is locked and communicating it to the network 70. The MS10 may similarly set the second countdown timer to the response time (Act _ timer — NW response time). This timer may be used by the MS10 to set when the MS10 transmits the determined location.

At time g, the elapsed time in this example is 36 seconds. The MS10 has used the overall allocated network response time in determining the position fix. Thus, even if location accuracy has not been reached, an accuracy-improved location has been found, potentially with greater accuracy (or similarly with less uncertainty) than requested by standard network accuracy (e.g., 51.2 meters).

By reducing this uncertainty parameter to 0, the MS10 will calculate a position fix using the overall allowable network response time. By reducing the uncertainty parameter to a low value (e.g., 1, 2, 3, or 4), the MS10 will most likely use the overall allowable network response time unless a position fix with low estimated uncertainty can be determined. The additional time used by the GPS engine to attempt to obtain a position fix with reduced necessary uncertainty gives the MS10 the opportunity to generate a position fix with increased accuracy.

At time g, the MS10 sends an RRLP Measure position response message 122 with one of the following components: location information; GSP-measurement information; or a position error. Typically, when the MS10 determines an acceptable position fix or times out, the MS10 will respond with a location information component. Alternatively, when the MS10 is instructed to provide measurements to the network 70, the MS10 will respond with a GSP measurement information component, which allows the network 70 to determine location based on this raw data.

Fig. 18 illustrates another embodiment of a call flow process for an Emergency Services (ES) call. In this scenario, the location request message is communicated immediately so that the MS10 replies with a punctual location response. The process begins as described above with reference to fig. 17. At time a (t-0), the MS10 identifies the ES call and then, in response, turns on the GPS engine. Again, an active countdown timer (Act _ timer ═ 40 seconds) is set. At time b, the network 70 sends a first RRLP assistance data message 140. At time c, the MS10 replies with an RRLP assistance data message 142. The process may continue to communicate multiple 140/142 sets of messages.

At time d, this scenario departs from the previously described scenario. At time d, the network 70 has information that it needs to send a location request message (RRLP measure location request message 120), however, the network 70 delays sending the message until a predetermined time before the network 70 needs a location fix. Standard network accuracy can be set to provide sufficient accuracy (NW accuracy 19, which represents 51.2 meters), however, network setup response time is drastically shortened. For example, instead of giving 10 seconds to the MS10, the NW response time may be set to 2 (representing 4 seconds) or to 1 (representing 2 seconds). This drastically reduced time does not normally allow the mobile station to determine a position fix. Typically, a mobile station requires tens of seconds to several minutes. Here, the MS10 has worked on its location for tens of seconds since it started its positioning process earlier (e.g., at time a).

Again, the network 70 prepares an RRLP measure position request message 120. The message 120 contains a drastically shortened network response time (e.g., NW response time of 4 seconds) and network accuracy (e.g., NW accuracy of 51.2 meters). At time e, the elapsed time in this example is 32 seconds, and the network 70 sends an RRLP measure position request message 120. In this case, the last set of assistance data segments is included in the previous message (i.e., the last RRLP assistance data message 140), so this message 120 is sent without assistance data.

In some cases, the accuracy used by the MS10 is set to a value representing low accuracy or equivalently representing high uncertainty (e.g., value 34 represents 245.5 meters), which may be a predetermined value or a predetermined configurable value. This accuracy value, which represents low accuracy, can be set in one of two ways: set by the network 70; or set by the MS 10.

If the accuracy value is set by the network 70, the network 70 sends an RRLP Measure position request message 120 with the network accuracy (NW accuracy) set to represent this low accuracy value. For example, the network 70 may temporarily overwrite the standard network accuracy with a low accuracy value for this MS 10.

On the other hand, if the accuracy is set by the MS 120, the network 70 may send an RRLP measure position request message 120 with the network accuracy set to represent the standard network accuracy. The MS10 overwrites or ignores the received network accuracy and instead uses a value representing low accuracy. The MS10 uses the network response time (NW response time) for both its internal countdown timer and its response time timer (i.e., Act _ timer ═ NW response time and Act _ RT ═ NW response time, respectively). At time f, once the response time timer is zero (36 seconds elapsed in this example), the MS10 prepares and sends an RRLP measure position response message 122.

This scenario has several advantages. An elevated position fix has been generated because the MS10 has started the GPS engine early (at time a) and has used the maximum possible duration of time to determine a position fix while minimizing battery power consumption. Since the RRLP measure position request message 120 is very short (because it does not contain assistance data), the likelihood that the message 120 will be preempted is reduced. Since the network response time is low (e.g., 4 seconds), the chance of the final RRLP session being interrupted by another RR message is reduced. If the standard network Accuracy (e.g. NW Accuracy 51.2 m) is replaced by a reduced Accuracy value (e.g. Act _ Accuracy 245.5 m), the chance that the final RRLP session is interrupted by another RR message is even further reduced.

Fig. 19 illustrates yet another embodiment of a call flow process for an Emergency Services (ES) call. In this scenario, the first location request message 120 (with or without assistance data) is communicated immediately after the final RRLP assistance data message 142. If this RRLP session is interrupted, the network 70 delays sending the recall location request message 120A (the message without assistance data) to a predetermined time based on when the location is needed. In addition, the flow of events and messages from time a to time f is the same as those described above with reference to fig. 17, and the description will not be repeated.

The sequence branches off from fig. 17 at time g, when the additional RR message 130 causes the current RRLP session to be interrupted. Equally, the RRLP measure position request message 120 may be pre-empted internally in the outgoing queue of the network (e.g., because the RRLP measure position request message 120 is long because it contains assistance data). In either case, the MS10 does not have a currently open RRLP session or an instruction to reply with a location.

The network 70 delays sending the recall message 120A to the calculated time to give the MS10 just enough time to reply with a position fix so that the position fix is received immediately for the network 70 to report. Based on the earlier RRLP session being interrupted or preempted, the network 70 may determine to switch from the first mode to the second mode. In the first mode, the network 70 sends a recall based on the prematurely stopped RRLP session and immediately sends a recall location request message once known. That is, the network 70 bases the past event, i.e., completion of the additional RR message, and the need to retransmit the location request message as quickly as possible on the time base of the next location request message.

In this second mode, the network 70 does not immediately send a recall location request message. Instead, the network 70 advantageously waits for a duration of time based on when a location response is required. That is, rather than basing the past event on the time base of the recall location request message, the transmission is based on a future event. For example, the timing of the next position request is based on when a position fix is needed (e.g., based on the remaining NW response time).

The timing of when to transmit the RRLP measure position request message 120 may be based on a predetermined time prior to the time that a position fix is required in the network 70. In the illustrated example, the predetermined time is set to 8 seconds before the network 70 requires location information (NW response time is 3). Other predetermined times may also be used, such as based on empirical data for each mobile station (e.g., NW response time may be set to 1, 2, 4, 8, or 16 seconds). The network 70 may set a timer or schedule the measurement request message so that it is transmitted at this future time.

At time h (t-32), the network 70 terminates the delay and transmits a recall RRPL measure location request message 120A. As indicated by the figure, the message does not contain assistance data. Alternatively, the delay in sending the recall RRPL measure location request message 120A may be slightly shortened, the response time (NW response time) may be slightly increased and the message 120A may contain some assistance data. Also, the accuracy parameter used by the MS10 may be set to a large uncertainty value (e.g., 245.5 meters) -either a standard network value is overwritten by the MS10 or a temporary uncertainty value is set by the network 70. The MS10 resets its activity timer to the network preset response time (Act _ timer ═ NW response time).

In this example, the mobile subscriber's activity timer is set to expire in 4 seconds (Act _ timer 4 seconds), but this timer is reset based on the time received (change to Act _ timer NW response time 8 seconds). The MS10 may set its response time to a network preset response time (Act _ RT — NW response time 8 seconds). At time i (t-36), the MS10 reports the determined position with an RRLP measure position response message 122, followed by turning off the GPS engine.

Fig. 20 shows such a scenario: where the network 70 transmits an immediate measurement request message but an earlier recall of the assistance data message results in the MS10 using a network preset accuracy. The events and messages at times a to d are the same as those of fig. 19. At time e, the session is interrupted by an additional RR message 144. Similarly, the network may have preempted the delivery of message 144. At times f and g, the assistance data is sent as a recall RRLP assistance data message 144A and acknowledged by an RRLP assistance data acknowledgement message 146. The recall message may be a recall of a first assistance data message (not shown), a second assistance data message (as shown), or any other sequence of segments of an assistance data message (not shown).

At time h (t-20), the network 70 sends an RRLP measure position request message 120 to receive the measurement report message immediately, as described above. The MS10 may set its activity timer to a network preset response time (Act _ timer ═ NW response time ═ 16 seconds), may set its response timer to a network preset response time (Act _ RT ═ NW response time ═ 16 seconds), and may set its Accuracy to a network preset Accuracy (Act _ Accuracy ═ NW Accuracy ═ 51.2 meters).

In the previous example, the MS10 normally uses an accuracy value that is a temporary value. This nonce value is a different value that is either greater or less than the standard network accuracy. In this example, standard network accuracy is used as an exception to using different values. Finally, at time i (t-36), the MS10 reports the determined measurements in an RRLP measure position response message 122.

In some cases, the network 70 may detect that a rebid (due to an interruption or preemption) occurred. In this case, the network 70 modifies the network preset accuracy from the temporary value to the standard network accuracy. Alternatively, the MS10 may detect the occurrence of a recall assistance data message (due to an interruption) and based on this event, the MS modifies its accuracy from that value. Alternatively, the MS may determine that the received measurement request message is delayed based on a measured time duration since a previous RRLP message.

Figure 21 shows a flow chart relating to the modification of the accuracy parameter from standard network accuracy as described with reference to the previous four figures. At 700, a determination is made whether the message 120 is sent and received on time, subsequent to the MS10 having received the RRLP measure position request message 120. This determination may be made by the MS10 or by the network 70 based on time (e.g., some expected communication time), based on interruption, or based on preemption, as described above. If the RRLP measure position request message 120 is on time, processing continues at step 710.

At step 710, the MS10 uses a higher than normal accuracy (e.g., 0 meters) for maximum accuracy or a selected smaller value (e.g., a value between 1 and 10 meters, or a value between 0 meters and a standard network accuracy value) than the standard network accuracy for a more accurate response.

If the RRLP measure position request message 120 is delayed, the accuracy may be set to standard network accuracy (not shown). Alternatively, if the RRLP measure position request message 120 is delayed, processing continues at step 720. Another test may be performed at step 720 to determine if the message 120 is delayed slightly or much later. For example, if a recall is made for the assistance data message, it may be determined that the RRLP measure position request message 120 is slightly delayed. If a recall is made to a previous RRLP measure position request message, it may be determined that the RRLP measure position request message 120 is much later. Alternatively, if the RRLP measure position request message 120 is communicated after a first predetermined time (e.g., 24 seconds) but before a second predetermined time, it may be determined that the RRLP measure position request message 120 is slightly delayed. If communicated after the second predetermined time, the RRLP Measure position request message 120 may be determined to be much later. At step 730, the MS10 uses standard network accuracy (i.e., NW accuracy). At step 740, the MS10 accelerates its position response using a lower accuracy value (e.g., 100, 200, or 250 meters).

Fig. 22 illustrates a message flow diagram for a Value Added Service (VAS) according to an embodiment of the present invention. For VASs, the MS10 need not use the entire amount of NW response time.

At time a (t ═ 0), the network 70 determines that a VAS has been initiated. In response, it sends an RRLP assistance data message 140. The MS10, upon receiving the RRLP assistance data message 140, turns on the GPS engine and sets its activity timer to a predetermined value (a value greater than that used in the ES call, e.g., Act _ timer 45 seconds). Also in response to receipt of the RRLP assistance data message 140, the MS10 transmits an RRLP assistance data confirmation message 142 at time b. At times c and d, additional segments of assistance data may be communicated and acknowledged with additional pairs of RRLP assistance data messages 144 and RRLP assistance data acknowledgement messages 146.

At time e (t-20, Act _ timer-25), the network 70 prepares an RRLP measure position request message with a standard network time (e.g., NW response time-16 seconds) and a standard network accuracy value (e.g., NW accuracy-51.2 meters). The network 70 sends an RRLP measure position request message 120 and the MS10 receives the RRLP measure position request message 120. Unlike an ES call, the MS10 does not discard any network preset parameters. The MS10 sets its activity timer, activity response timer, and activity Accuracy parameters to network preset values (i.e., Act _ timer _ NW response time, Act _ RT _ NW response time, and Act _ Accuracy _ NW Accuracy, respectively).

At time f (t-34, Act _ timer-2), the MS10 sends its determined location to the network 70 in an RRLP measure location response message 122. In this case, the MS sends the determined lock before the network response time expires because the location uncertainty is less than the required network accuracy. Finally, in response to reporting the determined lock, the MS10 turns off the GPS engine.

It should be understood that the invention can be practiced with modification and alteration and still be within the spirit and scope of the appended claims. It is not intended to be exhaustive or to limit the invention to the precise form disclosed. It is to be understood that the invention may be practiced with modification and alteration.

Claims

1. A method implemented in a network for reducing rebids of Measure position request messages between the network and a mobile station in a wireless network, the method comprising:

waiting to a predetermined time, wherein the predetermined time is based on a time at which location data is needed;

transmitting a Measure position request message including a network response time and a network accuracy at the predetermined time; and

receiving a Measure position response message including the position data at a time before the position data is needed.

2. The method of claim 1, wherein the network response time comprises a value representing a shortened response time of not greater than 4 seconds.

3. The method of claim 1, wherein the network accuracy comprises a value representing low accuracy of not less than 100 meters.

4. The method of claim 1, wherein the measure position request does not include assistance data.

5. The method of claim 1, further comprising:

transmitting an assistance data message; and

an assistance data confirmation message is received.

6. The method of claim 1, wherein the Measure position request message comprises an RRLP Measure position request message.

7. The method of claim 1, wherein the Measure position response message comprises an RRLP Measure position response message.

8. A method implemented in a network for reducing rebids of Measure position request messages between the network and mobile stations in a wireless network, the method comprising:

transmitting an RRLP assistance data message;

receiving an RRLP assistance data confirmation message;

transmitting an RRLP measure position request message at the predetermined time comprising a network response time and a network accuracy, wherein the network response time comprises a value representing a shortened response time of no more than 4 seconds, wherein the network accuracy comprises a value representing low accuracy of no less than 100 meters, and wherein the RRLP measure position request message does not include assistance data; and

receiving an RRLP Measure position response message including the position data at a time before the position data is needed.

9. A network for reducing rebids of measure position request messages between a network and a mobile station in a wireless network, the network comprising:

a timer to wait for a predetermined time, wherein the predetermined time is based on a time at which location data is needed;

a transmitter to transmit a Measure position request message including a network response time and a network accuracy at the predetermined time; and

a receiver to receive a Measure position response message including the position data at a time before the position data is needed.

10. The network of claim 9, wherein the network response time comprises a value representing a shortened response time of no greater than 4 seconds.

11. The network of claim 9, wherein the network accuracy comprises a value representing low accuracy of not less than 100 meters.

12. The network of claim 9, wherein the measure position request does not include assistance data.

13. The network of claim 9, wherein the Measure position request message comprises an RRLP Measure position request message.

14. The network of claim 9, wherein the Measure position response message comprises an RRLP Measure position response message.

15. An apparatus implemented in a network for reducing rebids of Measure position request messages between the network and a mobile station in a wireless network, the apparatus comprising:

means for waiting to a predetermined time, wherein the predetermined time is based on a time at which location data is needed;

means for transmitting a Measure position request message comprising a network response time and a network accuracy at the predetermined time; and

means for receiving a Measure position response message including the position data at a time before the position data is needed.

16. The apparatus of claim 15, wherein the network response time comprises a value representing a shortened response time of not greater than 4 seconds.

17. The apparatus of claim 15, in which the network accuracy comprises a value representing low accuracy of not less than 100 meters.

18. The apparatus of claim 15, wherein the measure position request does not include assistance data.

19. The apparatus of claim 15, further comprising:

means for transmitting an assistance data message; and

means for receiving an assistance data confirmation message.

20. The apparatus of claim 15, wherein the Measure position request message comprises an RRLP Measure position request message.

21. The apparatus of claim 15, wherein the Measure position response message comprises an RRLP Measure position response message.