Classifications

• • H—ELECTRICITY
  • H04—ELECTRIC COMMUNICATION TECHNIQUE
  • H04W—WIRELESS COMMUNICATION NETWORKS
  • H04W8/00—Network data management
  • H04W8/02—Processing of mobility data, e.g. registration information at HLR [Home Location Register] or VLR [Visitor Location Register]; Transfer of mobility data, e.g. between HLR, VLR or external networks
  • H04W8/08—Mobility data transfer

Definitions

• the present invention relates generally to routing telephone calls to mobile devices.
• the invention relates to routing calls in a Global System for Mobile Communications (GSM) network through a Mobile Switching Center (MSC) using a Home Location Register (HLR).
• GSM Global System for Mobile Communications
• MSC Mobile Switching Center
• HLR Home Location Register
• Telephone calls placed to mobile phones may not go through due to a variety of reasons.
• a called mobile phone may be busy, turned off, out of range of a wireless network, or may be otherwise non-reachable.
• callers often place repetitive additional calls to the called mobile phone until a call goes through and the called mobile phone is answered. Placing such repetitive additional calls is inconvenient and problematic as it wastes the time of callers, who must continual re- key a phone dialing sequence, and because it wastes wireless network resources that must repetitively route and process the additional voice calls (which generally receive high network priority) until a called phone is answered.
• GSM Global System for Mobile Communications
• HLRs store data about where in the network a particular mobile phone is operating.
• RAN Radio Access Network
• MSC Mobile Switching Center
• the MSC identifies the phone and informs an HLR associated with the phone that the phone is now operatively connected with the MSC. If an incoming call directed to the phone is then received in the network, the network first contacts the HLR associated with the phone to learn the identity of the MSC that is currently managing wireless communication with the phone. The incoming call is then routed through the MSC to the phone.
• the present invention is a method for routing calls in a mobile communication network.
• the method includes processing at a default Mobile Switching Center (MSC), a first request, received from a Home Location Register (HLR), for a roaming number associated with a Mobile Station (MS).
• the first request for a roaming number comprises a Network Resource Identifier (NRI) that identifies a first pool MSC to which the MS is registered.
• the first pool MSC is then identified at the default MSC using the NRI.
• the default MSC transmits, to the first pool MSC, a second request for a roaming number associated with the MS.
• Embodiments of the present invention therefore enable reducing a frequency of failed calls in a mobile communication network.
• MSC mobile switching centers
• All calls to mobile stations operating in the pool area will be processed first by a default MSC.
• the default MSC is not limited to transmitting requests for roaming numbers for a called mobile station to only a single MSC to which a called mobile station was last registered. Rather, the default MSC can iteratively contact each MSC from a plurality of MSCs operating in the pool area, until one of the pool MSCs is able to provide a roaming number for a particular called mobile station.
• QoS Quality of Service
• FIG. 1 is a schematic diagram illustrating components of a typical Global System for Mobile Communications (GSM) voice data communications network that connects a calling station to a mobile station (MS);
• FIG. 2 is a schematic diagram illustrating components of a conventional GSM system that includes a pool area;
• GSM Global System for Mobile Communications
• FIG. 3 is a schematic diagram illustrating components of a GSM system that includes a pool area and a default Mobile Switching Center (MSC), according to an embodiment of the present invention
• FIG. 4 is a schematic diagram illustrating a MAP UPD ATE LO CATION message transmitted from a first pool MSC to a Home Location Register (HLR), according to an embodiment of the present invention
• HLR Home Location Register
• FIG. 5 is a message sequence chart illustrating a method for routing calls in a mobile communication network that includes a pool area, according to an embodiment of the present invention.
• FIG. 6 is a general flow diagram illustrating a method for routing calls in a mobile communication network, from the perspective of a default MSC, according to an embodiment of the present invention.
• relational terms such as left and right, first and second, front and rear, and the like may be used solely to distinguish one entity or action from another entity or action without necessarily requiring or implying any actual such relationship or order between such entities or actions.
• the terms "comprises,” “comprising,” or any other variation thereof, are intended to cover a non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements does not include only those elements but may include other elements not expressly listed or inherent to such process, method, article, or apparatus.
• An element preceded by "comprises a . . .” does not, without more constraints, preclude the existence of additional identical elements in the process, method, article, or apparatus that comprises the element.
• a schematic diagram illustrates components of a typical Global System for Mobile Communications (GSM) voice data communications network 100 that connects a calling station 105 to a mobile station (MS) 110.
• the calling station 105 can be any type of station, such as a mobile phone or a wireline terminal, capable of connecting to a Public Land Mobile Network (PLMN) 115 in which the MS 110 operates.
• PLMN Public Land Mobile Network
• the calling station 105 To initiate a call from the calling station 105 to the mobile station 110, the calling station 105 first sends an incoming call setup signal, such as an Initial Address Message (IAM), to a Gateway Mobile Switching Center (GMSC) 120 associated with the PLMN 115. If the calling station 105 is another mobile device, the IAM is routed to the GMSC 120 through another PLMN. If the calling station 105 is a wireline terminal, then the IAM is routed to the GMSC 120 through a local exchange.
• IAM Initial Address Message
• the GMSC 120 After receiving the incoming call setup signal, the GMSC 120 transmits a Mobile Application Part (MAP) call setup message to a Home Location Register (HLR) 125 that is associated with the mobile station 110.
• the HLR 125 maintains subscriber data, such as a Mobile Subscriber Integrated Service Digital Network (MSISDN) number, associated with the called mobile station 110.
• MSISDN Mobile Subscriber Integrated Service Digital Network
• the HLR 125 also maintains an identity of a Mobile Switching Center (MSC) 130 and corresponding Visitor Location Register (MSC/VLR) that provides current service to the mobile station 110.
• the MAP call setup message sent to the HLR 125 comprises for example a MAP SEND ROUTING INFORMATION message that requests current routing information concerning the mobile station 110.
• the HLR 125 In response to the received call setup message, the HLR 125 thus uses the MSISDN of the called mobile station 110 to access information about the current location of the mobile station 110, and to identify the MSC 130 that is currently serving the mobile station 110. The HLR 125 then transmits a message to the MSC 130, such as a MAP PROVIDE RO AMING NUMBER message, requesting a roaming number associated with the mobile station 110. The MSC 130 responds by sending a MAP message back to the HLR 125, including a roaming number of the MSC 130, and the HLR 125 then forwards the roaming number to the GMSC 120.
• a message such as a MAP PROVIDE RO AMING NUMBER message
• a schematic diagram illustrates components of a conventional GSM system 200 that includes a pool area 205.
• a pool area is an area within which a mobile station can roam without needing to change its serving Core Network (CN) node, such as an MSC. Pool areas can therefore reduce the frequency of inter- CN node updates, handovers and relocations, and reduce the volume of HLR update traffic.
• CN Core Network
• the pool area 205 is served by one or more CN nodes, such as the first MSC 130, a second MSC 210, and a third MSC 215, all operating in parallel. All mobile stations, such as the mobile station 110, operating in the pool area 205 are controlled by a Radio Access Network (RAN) node 220.
• RAN node 220 can comprise for example a Radio Network Controller (RNC) or a Base Station Controller (BSC).
• RNC Radio Network Controller
• BSC Base Station Controller
• FIG. 3 a schematic diagram illustrates components of a GSM system 300 that includes a pool area 305 and a default MSC 310, according to an embodiment of the present invention.
• an HLR 315 that stores information concerning a mobile station that is operatively connected to a particular RAN node 320 in the pool area 305 will store only address information concerning the default MSC 310. That is, regardless of whether a particular RAN node 320 is currently managed by a first pool MSC 325 or a second pool MSC 330 in the pool area 305, the HLR 315 of a mobile station connected to that particular RAN node 320 will store only address information concerning the default MSC 310.
• a schematic diagram illustrates a MAP UPDATE LOCATION message transmitted from the first pool MSC 325 to the HLR 315, according to an embodiment of the present invention.
• a mobile station When a mobile station first connects to the pool area 305, it may be managed by the first pool MSC 325.
• the first pool MSC 325 transmits a MAP UPDATE LOCATION message to the HLR 315 that is associated with the mobile station, the message includes the address of the default MSC 310 and not the address of the first pool MSC 325.
• the MAP UPDATE LOCATION message also includes a Network Resource Identifier (NRI) of the first pool MSC 325.
• NRI Network Resource Identifier
• the default MSC 310 is then used to route requests for roaming numbers to particular MSCs, such as the first pool MSC 325, which manage communications with particular mobile stations.
• a message sequence chart 500 illustrates a method for routing calls in a mobile communication network that includes the pool area 305, according to an embodiment of the present invention.
• a call setup message such as a MAP SEND ROUTING INFORMATION message is transmitted from a Gateway Mobile Switching Center (GMSC) 510 to the Home Location Register (HLR) 315.
• the message identifies a called mobile station that is managed by the HLR 315.
• the HLR 315 transmits to the default Mobile Switching Center (MSC) 310, in response to the call setup message, a first request for a roaming number associated with the mobile station.
• MSC Mobile Switching Center
• the first request for a roaming number can be a MAP PRO VIDE ROAMING NUMBER message.
• the default MSC 310 then transmits a second request for a roaming number to the first pool MSC 325.
• the first pool MSC 325 is generally the MSC to which the mobile station that is the subject of the call setup message was last registered.
• the first pool MSC 325 is out of service, or is otherwise unable to process the second request from the default MSC 310, no response to the second request for a roaming number will be received at the default MSC 310.
• the first pool MSC 325 operates in the pool area 305, other MSCs are also operatively connected to the RAN node 320 that serves the mobile station to which the GMSC 510 is attempting to place a call.
• the default MSC 310 maintains a listing that identifies alternative MSCs that are also operating within the same pool area 305 as the first pool MSC 325. Therefore, when no response to the second request for a roaming number is received, the default MSC 310 selects from its listing the second pool MSC 330 in the pool area 305 covering the called mobile station. At line 525, the default MSC 310 transmits to the second pool MSC 330 a third request for a roaming number associated with the called mobile station. If the second pool MSC 330 is not out of service, it will receive and process the third request for a roaming number.
• the second pool MSC 330 will not be able to immediately provide a roaming number associated with the called mobile station.
• the second pool MSC 330 therefore transmits to the HLR 315 a request, such as a MAP RESTORE DATA message, for additional subscriber data concerning the called mobile station.
• the HLR 315 then transmits back to the second pool MSC 330 additional subscriber data, such as an International Mobile Subscriber Identity (IMSI) record, associated with the called mobile station.
• IMSI International Mobile Subscriber Identity
• the second pool MSC 330 transmits to the default MSC 310 a roaming number associated with the called mobile station.
• the default MSC 310 transmits the roaming number to the HLR 315.
• the HLR 315 is then able to respond to the call setup message from the GMSC 310, and a call can be established through the GMSC 310 and the second pool MSC 330 to the called mobile station.
• the default MSC 310 could simply select a third MSC (not shown) that is also in the pool area 305 that covers the called mobile station.
• the default MSC 310 is able to iteratively step through a process of transmitting a plurality of requests for roaming numbers to a plurality of MSCs in the given pool area 305, until one of the MSCs provides an appropriate roaming number to the default MSC 310.
• the default MSC 310 is potentially a critical point of failure in the pool area 305. That is, if the default MSC 310 is rendered out of service, then calls to all mobile stations operating in the pool area 305 will not go through. Therefore, the reliability of the default MSC 310 can be increased relative to the other pool MSCs 325, 330 using fault management processes such as equipment redundancies and 1+1 or N+l fault tolerance configurations, as known to those skilled in the art.
• a general flow diagram illustrates a method 600 for routing calls in a mobile communication network, from the perspective of the default MSC 310, according to an embodiment of the present invention.
• the default MSC 310 processes a first request, received from the HLR 315, for a roaming number of a called MS.
• the first request for a roaming number includes a Network Resource Identifier (NRI) that identifies the first pool MSC 325 as managing calls to the called MS.
• NRI Network Resource Identifier
• the default MSC 310 identifies the first pool MSC 325 using the NRI in the first request.
• the default MSC 310 transmits a second request for a roaming number of the MS to the first pool MSC 325.
• NRI Network Resource Identifier
• step 620 it is determined whether a response to the second request for a roaming number is received from the first pool MSC 325. If so, then at step 625 the roaming number is processed at the default MSC 310. At step 630 the roaming number is transmitted to the HLR 315, the call to the mobile station is completed, and the method 600 ends. However, if at step 620 a roaming number is not received from the first pool MSC 325, then the method 600 continues at step 635 where a third request for a roaming number is transmitted from the default MSC 310 to the second pool MSC 330.
• the second pool MSC 330 When the second pool MSC 330 receives the third request for a roaming number, the second pool MSC 330 will not recognize the called MS because the called MS was last registered with the first pool MSC 325, and not with the second pool MSC 330. Therefore the second pool MSC 330 will transmit to the HLR 315, in response to the third request for a roaming number, a request for additional subscriber data. The HLR 315 will then transmit additional subscriber data, such as an IMSI record associated with the called MS, to the second pool MSC 330. Only then will the second pool MSC 330 be able to identify a roaming number associated with the called MS and transmit it to the default MSC 310.
• additional subscriber data such as an IMSI record associated with the called MS
• a roaming number received from the second pool MSC 330, is processed at the default MSC 310.
• the default MSC 310 then transmits the roaming number to the HLR 315. The call to the MS then can be completed and the method 600 ends.
• Advantages of the present invention thus include reducing failed calls in a mobile communication network.
• MSCs mobile switching centers
• All calls to mobile stations operating in the pool area will be processed first by a default MSC.
• the default MSC is not limited to transmitting requests for roaming numbers for a called mobile station to only a single MSC to which a called mobile station was last registered. Rather, the default MSC can iteratively contact each MSC from a plurality of MSCs operating in the pool area, until one of the pool MSCs is able to provide a roaming number for a particular called mobile station.
• QoS Quality of Service
• the non-processor circuits may include, but are not limited to, a radio receiver, a radio transmitter, signal drivers, clock circuits, power source circuits, and user input devices. As such, these functions may be interpreted as steps of a method for routing calls in a mobile communication network. Alternatively, some or all functions could be implemented by a state machine that has no stored program instructions, or in one or more application specific integrated circuits (ASICs), in which each function or some combinations of certain of the functions are implemented as custom logic. Of course, a combination of the two approaches could be used. Thus, methods and means for these functions have been described herein.

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• Mobile Radio Communication Systems (AREA)

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• 2006
  • 2006-03-31 CN CN200610071028XA patent/CN101047969B/zh active Active
• 2007
  • 2007-03-12 DE DE112007000778T patent/DE112007000778B4/de active Active
  • 2007-03-12 WO PCT/US2007/063793 patent/WO2007117825A2/en active Application Filing

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