Telecommunications system

• US 5,926,759 A
• Filed: 07/29/1996
• Issued: 07/20/1999
• Est. Priority Date: 08/01/1995
• Status: Expired due to Fees

• Current Assignee: SELEX Sensors and Airborne Systems Ltd. (Leonardo S.p.A.)
• Original Assignee: GEC Marconi Limited (Gooding Consumer Electronics Ltd.)
• Inventors: Severwright, Robert Anthony
• Primary Examiner(s): Faile, Andrew
• Assistant Examiner(s): ONUAKU, CHRISTOPHER O
• Application Number:
  US08/688,159
• Time in Patent Office: 1,086 Days
• Field of Search: 455/33.1, 455/33.2, 455/33.4, 455/34.1, 455/34.2, 455/54.1, 455/56.1, 455/62, 455/67.1, 455/11.1, 455/63, 455/12.1, 455/98, 455/422, 455/427, 455/428, 455/431 , 455/436, 455/524, 455/525, 379/58, 379/59
• US Class Current: 455/431
• CPC Class Codes: H04W 48/20 Selecting an access point
• CPC Class Codes: H04W 84/06 Airborne or Satellite Networks space-based or airborne stations H04B7/185

Abstract

The invention provides a system and method whereby a mobile station of telecommunications system selects one of a number of fixed ground stations by which the mobile station communicates with the public switched telephone network or other such system, selection being made by the mobile station receiving selected criteria and deriving from a plurality of these criteria a score for each of a plurality of the fixed stations, the fixed station via which communication is to be made being selected in dependence upon the score derived for that fixed station.

Claims

1. A telecommunications system comprising at least one mobile station and a plurality of fixed stations with which the at least one mobile station can communicate, the at least one mobile station comprising processing means for receiving selected criteria, deriving from a plurality of those criteria a score for each of a plurality of fixed stations with which the at least one mobile station is able to communicate, and selecting on the basis of those scores the fixed station via which a transmission is to be routed, said score for each fixed station being derived from an algorithm into which the selected criteria are input, the processing means comprising means for receiving signals relating to the status of the mobile station and/or a fixed station for which it is determining a score, wherein said at least one criterion is multiplied by a constant associated with that criterion, the value of the constant being selected from one of a number of values depending on the status of the mobile and/or fixed station.

3. A system as claimed in claim 1 comprising a plurality of classes of fixed station and wherein the processing means has means for identifying the class to which a particular fixed station belongs and inserting a value in the algorithm in dependence upon the class of the fixed station for which a score is to be derived.

4. A system as claimed in claim 3, wherein at least some constants are selected in dependence on the class of fixed station.

6. A system as claimed in claim 1 wherein a transmission is rerouted during transmission if the score of an alternative fixed station exceeds that of the present fixed station by a predetermined value or ratio.

2. A telecommunications system comprising at least one mobile station and a plurality of fixed stations with which the at least one mobile station can communicate, the at least one mobile station comprising processing means for receiving selected criteria, deriving from a plurality of those criteria a score for each of a plurality of fixed stations with which the at least one mobile station is able to communicate, and selecting on the basis of those scores the fixed station via which a transmission is to be routed, said score for each fixed station being derived from an algorithm into which said selected criteria are input, the system comprising a plurality of classes of fixed station, wherein the processing means has means for identifying the class to which a particular fixed station belongs and inserting a value in the algorithm in dependence upon the class of the fixed station for which a score is to be derived.

5. A system as claimed in claim 2 wherein the fixed stations are categorised as macro, micro or pico stations.

28. A system as claimed in claim 2, wherein a transmission is rerouted during transmission if the score of an alternative fixed station exceeds that of the present fixed station by a predetermined value or ratio.

7. A terrestrial flight telephone system (TFTS) comprising at least one air station for location aboard an aircraft and a plurality of ground stations with which the at least one air station can communicate, the at least one air station comprising processing means for receiving selected criteria, deriving from a plurality of those criteria a score for each of a plurality of ground stations with which the at least one air station is able to communicate, and selecting on the basis of those scores the ground station via which a transmission is to be routed, said score for each particular ground station being derived from an algorithm into which the selected criteria are input, the processing means comprising means for receiving signals relating to the status of the air station and/or ground station for which it is determining a score, wherein said at least one criterion is multiplied by a constant associated with that criterion, the value of the constant being selected from one of a number of values depending on the status of the air and/or ground station.

9. A system as claimed in claim 7 comprising a plurality of classes of ground station and wherein the processing means has means for identifying the class to which a particular ground station belongs and inserting a value in the algorithm in dependence upon the class of the ground station for which a score is to be derived.

10. A system as claimed in claim 9, wherein at least some constants are selected in dependence on the class of ground station.

12. A system as claimed in claim 7 wherein a transmission is rerouted during transmission if the score of an alternative ground station exceeds that of the present ground station by a predetermined value or ratio.

30. A system as claimed in claim 9 comprising a number of ground stations categorized as airport ground stations, located at or close to airports, a number of intermediate ground stations and a number of en-route ground stations, wherein a algorithm implemented by said processing means, and constants associated with that algorithm, are such that selection of a transmission route to or from an air station located on an aircraft:

on the ground is biased in preference of an airport ground station;

on a plane taking off or landing in preference of an intermediate station; and

on a plane en-route in preference of an en-route station.

31. A system as claimed in claim 9 wherein the processor receives at least four of the following criteria:

closing rate to a ground station;

quality of signal to or from a ground station;

signal strength to or from a ground station;

the cell limit of a ground station;

the range to a ground station;

whether the aircraft with which the processing means is associated is on the ground; and

whether a ground station can be legally accessed.

32. A system as claimed in claim 9 employing the algorithm

8. A terrestrial flight telephone system (TFTS) comprising at least one air station for location aboard an aircraft and a plurality of ground stations with which the at least one air station can communicate, the at least one air station comprising processing means for receiving selected criteria, deriving from a plurality of those criteria a score for each of a plurality of ground stations with which the at least one air station is able to communicate, and selecting on the basis of those scores the ground station via which a transmission is to be routed, said score for each particular ground station being derived from an algorithm into which the selected criteria are input, wherein the system comprises a plurality of classes of ground station and wherein the processing means has means for identifying the class to which a particular ground station belongs and inserting a value in the algorithm in dependence upon the class of the ground station for which a score is to be derived.

11. A system as claimed in claim 8 wherein the ground stations are categorised as macro, micro or pico stations.

29. A system as claimed in claim 8, wherein a transmission is rerouted during transmission if the score of an alternative ground station exceeds that of the present ground station by a predetermined value or ratio.

13. A terrestrial flight telephone system (TFTS) comprising at least one air station for location aboard an aircraft and a plurality of ground stations with which the at least one air station can communicate, the at least one air station comprising processing means for receiving selected criteria, deriving from a plurality of those criteria a score for each of a plurality of ground stations with which the at least one air station is able to communicate, and selecting on the basis of those scores the ground station via which a transmission is to be routed, wherein the ground stations include a number of airport ground stations, located at or close to airports, a number of intermediate ground stations and a number of en-route ground stations, and wherein an algorithm implemented by said processing means, and constants associated with that algorithm, are such that selection of a transmission route to or from an air station located on an aircraft:

on the ground is biased in preference of an airport ground station;

on a plane taking off or landing in preference of an intermediate station; and

on a plane en-route in preference of an en-route station.

14. A terrestrial flight telephone system (TFTS) comprising at least one air station for location aboard an aircraft and a plurality of ground stations with which the at least one air station can communicate, the at least one air station comprising processing means for receiving selected criteria, deriving from a plurality of those criteria a score for each of a plurality of ground stations with which the at least one air station is able to communicate, and selecting on the basis of those scores the ground station via which a transmission is to be routed, wherein the processor receives at least four of the following criteria:

closing rate to a ground station;

quality of signal to or from a ground station;

signal strength to or from a ground station;

the cell limit of a ground station;

the range to a ground station;

whether the aircraft with which the processing means is associated is on the ground; and

whether a ground station can be legally accessed.

15. A terrestrial flight telephone system (TFTS) comprising at least one air station for location aboard an aircraft and a plurality of ground stations with which the at least one air station can communicate, the at least one air station comprising processing means for receiving selected criteria, deriving from a plurality of those criteria a score for each of a plurality of ground stations with which the at least one air station is able to communicate, and selecting on the basis of those scores the ground station via which a transmission is to be routed, wherein said processing means implements the following algorithm:

space="preserve" listing-type="equation"> S!.sub.gs =(k.sub.cr ×

C.sub.cr +k.sub.r ×

C.sub.r +k.sub.ss ×

C.sub.ss +k.sub.mr ×

C.sub.mr)k.sub.q ×

C.sub.q ×

k.sub.sl /k.sub.ho,

where S!_gs is the score for a particular ground station, C_cr is a function of the closing rate between said at least one air station and the particular ground station, C_r is a function of the range of said at least one air station from the particular ground station, C_ss is a function of the signal strength of a signal received by said at least one air station from the particular ground station, C_mr is a function of the maximum range of a cell served by the particular ground station, C_q is a function of a quality factor for the signal received by said at least one air station from the particular ground station, k_cr, k_r, k_ss, k_mr, and k_q are weighting constants for C_cr, C_r, C_ss, C_mr, and C_q, respectively, k_sl is a constant pertaining to whether the particular ground station can legally be accessed by the at least one air station, and k_ho is a constant pertaining to the position of said at least one air station with respect to a handover region around the particular ground station.

16. A method of selecting a cellular telecommunications system via which of a plurality of fixed stations a transmission with a mobile station is to be routed, the method comprising, for each of a plurality of fixed stations with which the mobile can communicate, receiving selected criteria and inputting these into an algorithm to derive a score for each fixed station, and deciding on the basis of the scores through which fixed station the transmission is to be routed, the method further comprising determining the status of the fixed station and/or mobile station, and multiplying the value of at least one criterion by a constant the value of which depends the status of the fixed station or mobile station.

18. A method as claimed in claim 16 comprising deploying fixed stations of different classes, identifying the class to which a fixed station belongs and inserting a value in the algorithm in dependence on the class of the fixed station for which a score is to be derived.

19. A method as claimed in claim 18 comprising selecting a value of at least some constants in dependence on the class of a fixed station for which a score is to be derived.

20. A method as claimed in claim 16 comprising rerouting a transmission if the score of an alternative fixed station exceeds that of the present fixed station by a predetermined value or ratio.

17. A method of selecting in a cellular telecommunications system via which of a plurality of fixed stations a transmission with a mobile station is to be routed, the method comprising, for each of a plurality of fixed stations with which the mobile station can communicate, receiving selected criteria and inputting these into an algorithm to derive a score for each fixed station, and deciding on the basis of the scores through which fixed station the transmission is to the routed, the method further comprising deploying fixed stations of different classes, identifying the class to which a fixed station belongs and inserting a value in the algorithm in dependence on the class of the fixed station for which a score is to be derived.

33. A method as claimed in claim 17, comprising rerouting a transmission if the score of an alternative fixed station exceeds that of the present fixed station by a predetermined ratio or value.

21. A method of selecting in a Terrestrial Flight Telephone System via which of a plurality of fixed ground stations a transmission to a mobile air station located aboard an aircraft is to be routed, the method comprising for each of a plurality of ground stations with which the mobile station can communicate, receiving selected criteria, inputting these into an algorithm to derive a score for each ground station, and deciding on the basis of the scores through which ground station the transmission is to be routed, the method further comprising determining the status of the ground station and/or respective air station, and multiplying the value of at least one criterion by a constant the value of which depends on the ground station or air station.

23. A method as claimed in claim 21 comprising deploying ground stations of different classes, identifying the class to which a ground station belongs and inserting a value in the algorithm in dependence on the class of the ground station for which a score is to be derived.

24. A method as claimed in claim 23 comprising selecting a value of at least some constants in dependence on the class of a ground station for which a score is to be derived.

25. A method as claimed in claim 21 comprising rerouting a transmission if the score of an alternative ground station exceeds that of the present ground station by a predetermined value or ratio.

22. A method of selecting in a Terrestrial Flight Telephone System via which of a plurality of fixed ground stations a transmission to a mobile air station located aboard an aircraft is to be routed, the method comprising for each of a plurality of ground stations with which the mobile station can communicate, receiving selected criteria, inputting these into an algorithm to derive a score for each ground station, and deciding on the basis of the scores through which ground station the transmission is to be routed, the method further comprising deploying ground stations of different classes, identifying the class to which a ground station belongs and inserting a value in the algorithm in dependence on the class of the ground station for which a score is to be derived.

34. A method as claimed in claim 22, comprising rerouting a transmission if the score of an alternative station exceeds that of the present ground station by a predetermined ratio or value.

35. A method as claimed in claim 22 comprising categorizing the ground stations into three classes:

airport, intermediate and en-route, and selecting through which ground station a transmission is to be routed by applying an algorithm, the algorithm and constants associated with that algorithm being selected such that if the air station is located in an aircraft on the ground the algorithm is biased in favour of selection of an airport ground station, if the aircraft is taking off or landing, biased in favour of selection of an intermediate ground station, and if en-route, biased in favour of an en-route ground station.

36. A method as claimed in claim 22 comprising making a selection of ground station in dependence on at least four of the following criteria:

closing rate to a ground station;

quality of signal to or from a ground station;

signal strength to or from a ground station;

the cell limit of a ground station;

the range to a ground station;

whether the aircraft with which the processing means is associated is on the ground; and

whether a ground station can be legally accessed.

26. A method of selecting in a Terrestrial Flight Telephone System via which of a plurality of fixed ground stations a transmission to a mobile air station located aboard an aircraft is to be routed, the method comprising for each ground station with which the mobile station can communicate, receiving selected criteria, inputting these into an algorithm to derive a score for each ground station, and deciding on the basis of the scores through which ground-station the transmission is to be routed, wherein the ground stations are categorized into three classes:

airport, intermediate and en-route, and wherein the algorithm and constants associated with that algorithm are selected such that if the air station is located in an aircraft on the ground the algorithm is biased in favour of selection of an airport ground station, if the aircraft is taking off or landing, biased in favour of selection of an intermediate ground station, and if en-route, biased in favour of selection of an intermediate ground station, and if en-route, biased in favour of en-route ground station.

27. A method of selecting in a Terrestrial Flight Telephone System via which of a plurality of fixed ground stations a transmission to a mobile air station located aboard an aircraft is to be routed, the method comprising for each ground station with which the mobile station can communicate, receiving selected criteria and deriving from a plurality of these score for each ground station, and deciding on the basis of the scores through which ground station the transmission is to be routed, wherein the selected criteria include at least four of the following criteria:

closing rate to a ground station;

quality of signal to or from a ground station;

signal strength to or from a ground station;

the cell limit of a ground station;

the range to a ground station;

whether the aircraft with which the processing means is associated is on the ground; and

whether a ground station can be legally accessed.