Classifications

• • H—ELECTRICITY
  • H04—ELECTRIC COMMUNICATION TECHNIQUE
  • H04W—WIRELESS COMMUNICATION NETWORKS
  • H04W4/00—Services specially adapted for wireless communication networks; Facilities therefor
  • H04W4/12—Messaging; Mailboxes; Announcements
• • H—ELECTRICITY
  • H04—ELECTRIC COMMUNICATION TECHNIQUE
  • H04B—TRANSMISSION
  • H04B7/00—Radio transmission systems, i.e. using radiation field
  • H04B7/14—Relay systems
  • H04B7/15—Active relay systems
  • H04B7/185—Space-based or airborne stations; Stations for satellite systems
  • H04B7/1853—Satellite systems for providing telephony service to a mobile station, i.e. mobile satellite service
  • H04B7/18567—Arrangements for providing additional services to the basic mobile satellite telephony service
• • H—ELECTRICITY
  • H04—ELECTRIC COMMUNICATION TECHNIQUE
  • H04M—TELEPHONIC COMMUNICATION
  • H04M3/00—Automatic or semi-automatic exchanges
  • H04M3/42—Systems providing special services or facilities to subscribers
  • H04M3/50—Centralised arrangements for answering calls; Centralised arrangements for recording messages for absent or busy subscribers ; Centralised arrangements for recording messages
  • H04M3/53—Centralised arrangements for recording incoming messages, i.e. mailbox systems
  • H04M3/533—Voice mail systems

Definitions

• This invention relates to the provision of a telecommunication link between a first and second telecommunication station, with an improved messaging service.
• the invention finds particular but not exclusive application to satellite communication systems for providing telecommunication coverage to mobile stations, such as mobile telephone handsets.
• LEO low earth orbit
• Mobile handsets for this 20 system are configured to establish a link to an overhead orbiting satellite, from which a call can be directed to another satellite in the constellation and then typically to a ground station which is connected to conventional land- based networks.
• a voicemail facility is usually provided so that if a user's mobile handset is switched off, the caller is offered the facility so that a recorded voice message can be left. The recorded message can then be retrieved by the user of the mobile handset when the user decides to interrogate the mailbox.
• GSM Global System Mobile
• the present invention includes from a first aspe ⁇ , a method of providing a telecommunication link between a first and a second telecommunication station, including offering a messaging service for use by a party at one of said stations in the event that the link drops out during use thereof, so as to permit a message to be stored and retrieved by another party after the dropout.
• one of the parties can record a message by means of the service in the event of the dropout, and the other party can then retrieve the message after the dropout.
• the method according to the invention has particular application to satellite global mobile systems, which may be prone to dropout, and offers a convenient way for a terminating message for the call to be left, in the event that a dropout occurs.
• the method according to the invention also may be used with conventional terrestrial mobile system, in the event of a dropout.
• the messaging service is offered to the calling party in the event that the link drops out.
• the calling party may be billed for both the call over the link and the use of the messaging service.
• the messaging service is offered to the called party at the first station in the event that the link drops out.
• the calling party is billed for the call over the link and the called party may be billed for the messaging service although other billing options for the messaging service may be provided.
• the system may include means responsive to dropout of the link for rendering the messaging service operative during the dropout. Means may be included for signalling subsequent to the dropout, that a message has been recorded and is available for retrieval.
• the second station may comprise a mobile station, such as a mobile telephone handset, j
• the network control means may include location register means for keeping a record of the location of the mobile station for routing the telecommunication link through the network between the gateway means and the transmission 20 station appropriate for establishing the communication path for the mobile station.
• the location register means may comprise a plurality of visitor location registers associated with the transmission stations respe ⁇ ively, for keeping a record of the mobile stations within the operational range thereof, and a home location register that receives data from the visitor location registers.
• the transmission stations may comprise satellite access nodes for establishing a communication path with the mobile station via at least one satellite.
• the o satellite access nodes may be operative to communicate with a constellation of MEO satellites in intermediate earth orbits.
• the transmission stations may be operative to communicate with a constellation of satellites in low earth orbits or geostationary orbits.
• the transmission stations may comprise base stations of a GSM mobile telephone system or other digital network.
• the invention also extends to a mobile station, such as a mobile telephone handset, for use in a telecommunication system which provides a telecommunication link therewith and another party, the mobile station being operative to communicate with a messaging service provided by the system in the event of dropout of the link, to receive an indication that the message has been recorded in the service as a result of dropout, and to retrieve the recorded message.
• a mobile station such as a mobile telephone handset
• FIG. 1 is a schematic block diagram of a mobile telecommunication system in accordance with the invention.
• Figures 2a to 2e illustrate how the voicemail is used in the event of a drop our for a call initiated by a land-based subscriber
• Figures 3a to 3e illustrate how the voicemail is used in the event of a dropout for a call initiated from a mobile handset.
• a mobile station 1 in the form of a mobile telephone handset can communicate on a radio channel over a communication path 2, 3 via an earth orbiting satellite 4, with a satellite access node SAN2.
• the SAN is provided with an antenna which can track the orbiting satellite.
• a number of the satellite access nodes, SANl, 2 etc are connected together in a network 5, which is connected through a number of gateways GW1, 2 etc to conventional earth based telephone networks.
• gateway GWl it is connected to a land-based public switch telephone network (PSTN) 6, which permits connection to be made to a conventional telephone set 7.
• PSTN public switch telephone network
• the satellites are typically arranged in a MEO constellation, for example with an orbital radius of 10,355 km, although the invention is not restri ⁇ ed to a particular orbital radius, as will be explained hereinafter.
• the satellites orbit the earth and are consequently tracked by the antenna of each SAN.
• the SANs are spaced around the earth in order to provide continuous coverage.
• SANl may be located in Europe, whereas SAN2 may be located in Africa, other SANs are located in the American continents and elsewhere.
• Each satellite such as satellite 4, is provided with a multiple beam forming antenna which transmits a plurality of spaced beams towards the earth, typically at different frequencies, the beams providing adjacent cellular areas, which correspond to the cells of a conventional land-based mobile telephone system.
• An antenna may use a beam former that utilises a Butler matrix device as described in GB 9407669.2.
• the antenna may be provided with a beam steering arrangement in order to keep the cellular pattern located in a constant geographical area for given periods, as the satellite orbits the earth.
• each SAN has an associated visitor location register (VLR) which operates in a similar manner to the visitor location register of a conventional GSM terrestrial mobile telephone system.
• VLR1 keeps a record of the handsets, such as handset 1, within the operational range of SANl.
• the handset 1 periodically transmits an identification signal which is dete ⁇ ed at SANl and the presence of handset 1 is then recorded in VLR1.
• HLR home location register
• the HLR operates in a similar way to a conventional GSM home location register and permits calls to be routed to the current location of the mobile handset.
• the network performs a number of administration fun ⁇ ions, such as accumulating data concerning calls made by the subscribers, and their billing addresses so that bills can be sent to each subscriber. This is condu ⁇ ed at an administration data centre ADC. Also, information concerning new users, derived from point of sale operators may be entered into the HLR at the ADC.
• the gateway GW1 may be operated by a land-based telephone operator and may typically comprise a conventional land-based international access node, for which the network 5 has an individual international dialling code.
• the current location of the handset 1 is determined by SANl requesting the information from the HLR.
• the call is then routed to the SAN appropriate for the current handset location.
• the call is routed to SAN2 from which it is routed over communication path 3 to the satellite 4, and then re-transmitted by the satellite on path 2, to the handset 1.
• the path 2 comprises one of the plurality of beams transmitted from the multibeam antenna of the satellite 4.
• the paths 2, 3 are bidire ⁇ ional.
• SAN2 monitors the duration of the call and sends timing information to the ADC for billing purposes.
• the user of handset 1 When a voicemail message is left in the mailbox, the user of handset 1 is notified by means of an appropriate display on the display panel la of the handset terminal.
• the notification message may tell the user of the number of unread messages in the voice box.
• the handset terminal may confirm receipt of the notification message, back to the network 5.
• the HLR may also operate as the HLR and voicemail facility for a land-based digital network, such a GSM network (not shown) conne ⁇ ed to the HLR as shown schematically by line 9.
• a GSM network not shown
• the voicemail fun ⁇ ions may be shared by the satellite and GSM networks.
• This message can be read by the user of handset 1 at the end of the call dropout.
• the voicemail facility VM provides a signal to the handset 1 via SAN2 and satellite 4, that a message is available for retrieval.
• the user of the handset 1 may then access the mailbox using the keypad lb, in the manner previously described.
• the voicemail facility as previously described can be adapted for use when a call is made between two mobile stations via the satellite link.
• the voicemail facility may be offered to the handset which does not suffer dropout of its associated satellite communication path, to enable a voicemail message to be recorded and subsequently retrieved by the other handset.
• the invention has been described in relation to a MEO satellite constellation, it is also applicable to a LEO constellation, in which communication links are established from a ground station to a first satellite and then to a second satellite before being dire ⁇ ed earthward to a mobile station. It is also applicable to use with a geostationary satellite.
• the invention is applicable to conventional land-based mobile telephone systems, for example a conventional GSM system in order to provide a voicemail facility in the event of a call dropout, for example when the use of a handset moves inside a building or into a tunnel, or some other region which produces a call dropout.
• a conventional GSM system in order to provide a voicemail facility in the event of a call dropout, for example when the use of a handset moves inside a building or into a tunnel, or some other region which produces a call dropout.
• the mobile station comprises a mobile handset, it could comprise a vehicle based station or other mobile device. Furthermore, the mobile station could a ⁇ ually be located at a fixed, or semi ⁇ fixed location such as a boat or other maritime location.
• the described example of the invention uses a voicemail facility, but other messaging services could be used, for example data, graphical or text based e.g. facsimile systems.

Landscapes

• Engineering & Computer Science (AREA)
• Signal Processing (AREA)
• Computer Networks & Wireless Communication (AREA)
• Physics & Mathematics (AREA)
• Astronomy & Astrophysics (AREA)
• Aviation & Aerospace Engineering (AREA)
• General Physics & Mathematics (AREA)
• Radio Relay Systems (AREA)
• Mobile Radio Communication Systems (AREA)

Applications Claiming Priority (3)

Publications (1)

Family

ID=10785961

Family Applications (1)

Country Status (6)

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Family Cites Families (2)

• 1995
  • 1995-12-22 GB GBGB9526367.9A patent/GB9526367D0/en active Pending
• 1996
  • 1996-12-18 AU AU11999/97A patent/AU1199997A/en not_active Abandoned
  • 1996-12-18 WO PCT/GB1996/003127 patent/WO1997023963A2/en not_active Application Discontinuation
  • 1996-12-18 JP JP9523390A patent/JP2000500945A/ja active Pending
  • 1996-12-18 EP EP96943203A patent/EP0811278A2/en not_active Withdrawn
  • 1996-12-19 ZA ZA9610700A patent/ZA9610700B/xx unknown

Non-Patent Citations (1)

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