Classifications

• • H—ELECTRICITY
  • H04—ELECTRIC COMMUNICATION TECHNIQUE
  • H04W—WIRELESS COMMUNICATION NETWORKS
  • H04W64/00—Locating users or terminals or network equipment for network management purposes, e.g. mobility management

Definitions

• the present invention relates to a method and system method of retrieving position information about a position of a Mobile Station in a cellular network, the network comprising Mobile Switching Centre Service Control Function, Nisitors Location Register, Host Location Register and Location Services Arrangement, and said MS having at least two operational modes: active and inactive.
• TA Timing Advance
• US 6,081,711 discloses a mechanism that guarantees the availability of necessary location data within a mobile communication network and also the transfer thereof to the appropriate network node when needed a mobile station (MS) for use in the digital cellular communication network supporting unstructured supplementary service data comprises service means to perform the standard services between the mobile station (MS) and the digital cellular communication network, interface means to perform the machine interface functionalities at the mobile station (MS), and unstructured supplementary service data means to establish a transaction channel to the digital cellular communication network for the interface transfer of unstructured supplementary service data.
• location information indicating means are adapted to identify a cell identifier for a cell within the digital cellular communication network where the mobile station (MS) is roaming and also to output the cell identifier via the unstructured supplementary service data interface means. According to the invention it is possible to use the most exact location information to provide location specific services from the network side in a digital cellular communication network.
• the position of a mobile station in a cellular mobile telephone system is determined by carrying out a simulated call setup, i.e., the call setup is interrupted subsequent to a telephone-switching center (MSC) having received a paging response containing the identity of the cell and, optionally, a timing advance.
• the simulated call setup is initiated by generating a modified short message signal (SMS), which is not registered in the SMS catalogue of the mobile station and which is not shown to the user of the mobile station.
• SMS modified short message signal
• the SMS commands the mobile station to carry out a position determining sequence in order to establish parameters for use in establishing the position of the mobile station, for example by commanding the mobile station to connect itself to a base station contained in its neighbor list, analyze the geographical position of the base station, and subsequently send the position determining parameters to a position handler.
• the geographical position of the base station is analyzed from the cell identity and, if available, the timing advance, the position of the mobile station being presented graphically on a picture screen and constantly updated after each call setup.
• the position handler generates the call setups.
• the SMS is modified such that the message includes a unique character sequence, e.g. ($$ ⁇ ), and it includes additional data associated with the order or command.
• a telecommunications system and method for providing location information consist of either real-time data or historical data when the subscriber requested to be positioned is either absent or not reachable, to a requesting location application (LA).
• the historical data is preferably stored per subscriber in a database within a serving Mobile Switching Center/Visitor Location Register (MSC/VLR) following a successful positioning of that subscriber.
• This historical data can consist of the location information along with a time stamp indicating the time that the location information was obtained and stored in the MSC/VLR.
• the age of the location information can then be calculated by determining the difference between the current read value of the system clock and the value of the time stamp information stored in the MSC/VLR for that particular location information.
• the messages are sent through Gateway Mobile Network (GMLC)
• the main object of the present invention is to provide an arrangement and a method, which overcomes the above-mentioned drawbacks, i.e., for the terminal centric methods, provide a support for the legacy of the mobile stations, and for the network centric methods eliminate requirement of upgrading base station systems.
• the initially described method comprises the steps of directing by said LSA a request message to said VLR to obtain location information about said MS, said request comprising of a message defined in a network communication protocol.
• said message is
• ATI AnyTimel terrogation (ATI) and/or ProvideSubscriberlnfo (PSI), and said ATI is sent through said HLR.
• PSI ProvideSubscriberlnfo
• said LSA comprises of a Service Control Function, a Location Centre Function and Short Message Service Central.
• the reply to said request from said VLR is controlled by said LSA, and if said reply contains information which does not meet certain criteria indicating that said MS is in an inactive mode, said MS is forced into an active mode by sending a short message, which updates information in said VLR. In this way also deactivated MSs are positioned.
• the criteria include location area information and/or location area information of certain age.
• said short message is one of SMS or USSD, without a need for modification of the short message.
• the last known serving cell is updated and subsequently the information through a LocationQuery is retrieved.
• the VLR does not store the last known serving cell information and returns only cell id information when a MS is in active mode.
• the cell id information is accessed by sending repeated LocationQuery requests during sending of the short message and the requests are based on a forced poll.
• the LSA which originates said requests has detailed information about signaling and the delivery of the short message is realized using ForwardSM operation and it triggers paging in the MSC, and that the serving cell information is not be available in the MSC/VLR until it receives a paging response from the MS.
• a time period between the dispatch of ForwardSM and paging response from MS can be estimated and to reduce the number of ATI requests, the first request is delayed until the estimated time.
• the ATI request is repeated until a valid result has been returned or a delivery confirmation is received for the short message and when the short message has been delivered the MS returns to idle mode.
• a ForwardSM operation is carried out, which includes a flag, MoreMessagesToSend (MMS), whereby the MSC maintains its radio resources towards the MS until a disabling message is delivered.
• MMS MoreMessagesToSend
• LSA has detailed knowledge about operations performed, it issues an ForwardSM with MMS enabled, followed by an ATI request and then a new ForwardSM with MMS disable is issued to release the radio resources.
• SCF can cooperate with a Location Centre Function (LCF) with the capability to transform the returned results into other geographical information.
• LCF Location Centre Function
• the LSA is arranged to choose from different location providers. This allows use of different position providers
• the LSA is provided with information about a mapping between a MS International ISDN Number (MSISDN) and an International Mobile Subscriber Identity (MSI) and current VLR for the MS, whereby a PSI request is directed directly to said VLR.
• MSISDN MS International ISDN Number
• MSI International Mobile Subscriber Identity
• the collections is through issuing one of the SendRouting operations in GSM, including SendRoutinglnfoForSM, and then derive a VLR number of the MSC number.
• the information is collected through any type of subscriber activity including USSD or SMS. It may also be collected using signaling link monitoring on some or the entire actual network nodes to track changes in current VLR.
• the cache is distributed among several nodes.
• the cache entry is simply invalidated and the normal procedure to collect the mapping information between MSISDN and IMSI, VLR is performed and the (distributed) cache is updated.
• the invention also relates to a system for retrieving position information about a position of a Mobile Station in a cellular network, the network comprising a Mobile Switching Centre (MSC), Service Control Function (SCF), Visitors Location Register (VLR), Host Location Register (HLR) and Location Services Arrangement (LSA).
• MS has at least two operational modes: active and inactive.
• the LSA is arranged to direct a request message to said VLR to obtain location information about said MS, said request comprising of a message defined in a network communication protocol.
• the message is AnyTimefriterrogation (ATI) and/or ProvideSubscriberlnfo (PSI).
• Fig. 1 is a schematic block diagram illustrating a communications network according to the invention
• Fig. 2 illustrates the signalling structure in the communications network according to the invention.
• ATI AnyTimelnterrogation
• MS Mobile Stations
• LocationQuery will be used to indicate use of AnyTimelnterrogation or the alternate method.
• FIG. 1 A block diagram of a communications network 100, such as GSM, AMPS etc., incorporating a system 110 according to the invention is illustrated in fig. 1.
• the communications network 100 basically comprises a number of base station antennas 120 connected to a number of MSCs 130 (Mobile Switching Centres), which operate in a known way.
• MSCs 130 Mobile Switching Centres
• the function of the GSM (or similar networks) is assumed to be well known to a skilled person and not described in detail herein.
• LCF Service Control Function
• VLR Visitors Location Register
• HLR Host Location Register
• LCF Location Centre Function
• SMSC Short Message Service Central
• LCA Location Services Arrangement
• the Service Control Function (SCF) 140 of a Location Service initiates a transaction with the Host Location Register (HLR) 160 through SRI SM (SendRoutinglnfo ForSM), which returns a result for the invoke request. Then a ForwardSM message is directed to the VLR 140, which returns a Result to the Invoke message. Then SCF 140 requests information from HLR 160 by sending an ATI Request (ATIR). The HLR relays this request to the current VLR (Visitors Location Register) 140 in form of a ProvideSubscriberlnfo (PSI) message. The result is returned via HLR to SCF.
• ATIR ATI Request
• PSI ProvideSubscriberlnfo
• the information about the current serving cell for the mobile station will always be returned when the mobile station is in active mode.
• the location information is needed, it is not always the case that the target Mobile Station is in active mode.
• Reasons could include requesting services via a disconnecting transport, such as SMS, or some other entity or when a user wants access the location information.
• the SCF may inspect the returned location information and if it does not meet certain quality criteria, i.e., for example only location area is returned or the information is too old, the SCF can force the target mobile station to active mode, e.g. in cooperation with a Short Message Centre (SMSC) 180 to send a Short Message (SM) and thereby update the location information in VLR.
• SMS Short Message Centre
• the message could also intentionally be a normal short message notifying the user that the location of the MS is being accessed.
• this procedure is enough to update the last known serving cell and subsequently retrieve the information through a LocationQuery.
• a VLR implementation does not need to store the last known serving cell information and returns only cell id information when a mobile station is in active mode. In this case there are two alternate methods to access the cell id information:
• a first method is based on repeated LocationQuery requests during sending of the short message.
• the polling may either be an ordinary (forced) poll without any intelligence but it may also be refined, where the request originator, i.e. LCF, has more detailed knowledge about the signaling.
• the delivery of the short message is realized using the ForwardSM operation (or one of its successors, such as MO-ForwardSM, MT-ForwardSM, etc. defined in different MAP versions). This operation triggers a paging in the MSC.
• the serving cell information will not be available in the MSC/VLR until it receives a paging response from the mobile station.
• the time between the FW SM and PagerResponse from MSC can be estimated and to reduce the number of ATI requests, the first request may be delayed until the estimated time.
• the ATI request can be repeated until a valid result has been returned or a delivery confirmation is received for the short message.
• the mobile station When the short message has been delivered the mobile station returns to idle mode.
• a feature in the MAP Phase 2 protocol is utilized.
• MMS MoreMessagesToSend
• the MSC will maintain the radio resources towards the mobile station until a short message is delivered with the indication disabled.
• the originating entity LCF
• it may issue ForwardSM with MMS enabled, followed by an ATI request and then issue a new ForwardSM with MMS disable to release the radio resources.
• the SCF can cooperate with a Location Centre Function (LCF) with the capability to transform the returned results into other geographical meaningful information.
• LCF Location Centre Function
• the LCF can provide the necessary privacy enhancement features requested by the subscriber.
• the LCF can be arranged to choose from different location providers, including LCS defined ones.
• the originating entity in order to perform a location request using ATI, the originating entity must always query the HLR. The HLR will then issue a PSI request towards the VLR to obtain the current location and status. The originating entity can issue a PSI request towards the VLR directly, if it knows the mapping between the Mobile Station International ISDN Number (MSISDN) and International Mobile Subscriber Identity (TJVISI) and current VLR for the mobile station. This information, i.e.
• MSISDN Mobile Station International ISDN Number
• TJVISI International Mobile Subscriber Identity
• the mapping information between the Mobile Station International ISDN Number (MSISDN) and International Mobile Subscriber Identity (-MSI) and current VLR can be collected using a number of methods and stored in a cache.
• One method would be to issue one of the SendRouting operations in GSM, including but not restricted to SendRoutinglnfoForSM, and then derive the VLR number of the MSC number.
• An alternate method is to collect the information on any type of subscriber activity including USSD or SMS.
• the MSC or HCR may use (optionally) standard and/or property information elements to indicate -MSI, VLR or MSISDN.
• Yet another method would be to collect the information using signaling link monitoring on some or the entire actual network nodes to track changes in current VLR.
• the cache mechanism can easily be distributed among several node elements and the consuming entity does not have to be the same as the collecting entity.
• the cache entry is simply invalidated and the normal procedure to collect the mapping information between MSISDN and ⁇ IMSI, VLR ⁇ is performed and the (distributed) cache can be updated.
• USSD Unstructured Supplementary Service Data
• SMS Short Supplementary Service Data
• the service logic can then use the MSISDN received in the original USSD or SMS request to perform a LocationQuery. Preferably, this action is performed prior to acknowledging the original request and the mobile station will still be in active mode.
• the location information may then be automatically transferred to the service application in addition to the service request information.
• the signalling to the VLR can involve any type of messages that return information about the subscriber mobile station's location and or status.

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• Engineering & Computer Science (AREA)
• Computer Networks & Wireless Communication (AREA)
• Signal Processing (AREA)
• Mobile Radio Communication Systems (AREA)

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• 2001
  • 2001-10-26 EP EP01979183A patent/EP1334638A2/de not_active Withdrawn
  • 2001-10-26 AU AU2002211168A patent/AU2002211168A1/en not_active Abandoned
  • 2001-10-26 WO PCT/SE2001/002360 patent/WO2002035752A2/en not_active Application Discontinuation

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