Method, exchange, telecommunication system and mobile station for temporary selective national roaming at predetermined network operation conditions in a mobile radio communication system

• US 6,463,286 B1
• Filed: 07/30/1999
• Issued: 10/08/2002
• Est. Priority Date: 07/31/1998
• Status: Expired due to Term

• Current Assignee: Telefonaktiebolaget LM Ericsson
• Original Assignee: Telefonaktiebolaget LM Ericsson
• Inventors: Salminen, Reijo
• Primary Examiner(s): Urban, Edward F.
• Assistant Examiner(s): ZEWDU, MELESS NMN
• Application Number:
  US09/362,985
• Time in Patent Office: 1,166 Days
• Field of Search: 455/432, 455/435, 455/436, 455/438, 455/439, 455/453, 455/560
• US Class Current: 455/453
• CPC Class Codes: H04W 36/0066 of control information between different types of networks in order to establish a new radio link in the target network

Abstract

The invention relates to a method, an exchange, a telecommunication system and a mobile station for providing a temporary selective national roaming at predetermined network operation conditions, e.g. at network overload in a mobile radio communication system. A first switching means (MSC/VLR) of a home network (HPLMN) performs a negotiation with a second switching means (MSC/VLR′) of another network (VPLMN) which has free capacity to handle mobile stations (MS1-MS4) of the first network (HPLMN) which cannot be handled by said first network (HPLMN) during e.g. an overload condition occuring therein. When e.g. the overload condition occurs, a request message (RM) is first sent to the second switching means (MSC/VLR′) in order to enquire whether the second network (VPLMN) has enough free capacity to take over mobile stations (MS1-MS4) from the first network (HPLMN). Thus, it can be ensured that mobile stations (MS1-MS4) of the first network (HPLMN) do not cause an overload condition in the second network (VPLMN) when they have been registered in the second network (VPLMN) and receive a service therein.

Claims

1. Telecommunication system comprising a first and at least one second mobile radio communication network, wherein one or more mobile stations of the first network are temporarily granted access in the second network at overload conditions in the first network, comprising

in the first network:

a) an overload detection means detecting an overload condition in the first network;

b) a first switching means including request means for sending to a second switching means of the second network a request message requesting that one or more mobile stations of the first network which cannot be handled in the first network due to said overload condition be handled by the second network, the request message indicating the number of mobile stations to be handled by the second network; and

in the at least one second network;

c) a reception means for receiving said request message from the first switching means;

d) an access grant means for determining whether the second network has enough capacity to handle calls of said one or more mobile stations which cannot be handled by the first network and for granting access for the mobile stations if there is enough capacity;

e) a response message sending means for sending a response message to said first switching means indicating that said second network grants access to one or more mobile stations of the first network which cannot be handled during said overload conditions if said access grant means determines that the capacity is sufficient; and

in at least one of the first and second network;

f) a registering means for registering the one or more mobile stations, which cannot be handled in said first network, in said second network.

3. A method according to claim 1, wherein said request message indicates at least one access class of mobile stations to be handled by the second network.

4. A method according to claim 3, wherein several second networks are provided and said switching means of the first network determines on the basis of the access classes of the mobile stations in which second network the at least one of said mobile stations of the first network should be registered.

5. A method according to claim 3, wherein several request messages are sent separately to several switching means in the second network each request message containing a number of mobile stations of a particular access group.

6. A method according to claim 1, wherein

as the predetermined operation condition an overload condition is detected in the first network.

7. A method according to claim 6, wherein said request message indicates one or more mobile stations of the first network which cannot be handled in the first network due to said overload condition, said response message indicates that the second network grants an access to the one or more mobile stations of the first network which cannot be handled during said overload condition and the one or more mobile stations which cannot be handled in the first network are registered in said second network.

8. A method according to claim 7, wherein said request message indicates information about the overload area in the first network.

9. A method according to claim 7, further comprising

in response to receiving said response message from the second network, sending an overload message to the base station controllers connected to the switching means of the first network indicating that a roaming to the second network is allowed for the at least one mobile stations of the first network due to said overload condition, said base station controllers providing said overload message to the mobile stations indicated therein.

10. A method according to claim 9, wherein said overload message indicates the at least one access class for which a roaming to said second network is allowed, said base station controllers providing said overload message to the mobile stations belonging to the indicated access class.

11. A method according to claim 9, wherein said overload message indicates at least one of the at least one second network to which the mobile stations are allowed to roam and a particular switching means of said at least one second networks.

12. A method according to claim 6, wherein in said step a) an operation condition detection means in the at least one mobile stations detects said overload condition if a call-setup request issued by said mobile station fails or if an on-going communication is interrupted;

and

said at least one mobile stations send a transfer request to said first switching means for actively requesting a transfer to the second network.

13. A method according to claim 12, wherein said transfer request indicates the desired second network to which a transfer is requested.

14. A method according to claim 6, wherein when said mobile station receives a release message after the end of said overload conditions, said mobile station sends a transfer request to the switching means of the second network indicating a desired first network where the re-registering is to be performed.

15. A method according to claim 1, wherein as said predetermined operation condition, at least one of a maintenance condition and a switching command by at least one or more mobile users is detected in the first network.

16. A method according to claim 1, wherein in step b) said request message is sent to at least two switching means of the second network.

17. A method according to claim 1, wherein several second networks are provided and said request message is sent to at least one switching means in each second network.

18. A method according to claim 17, wherein when a mobile station, which has been registered in said second network moves outside said allowable location area, said switching means of the second network decides either to continue a call or to perform an inter-network handover to the first network or to yet another second network, or to release the call.

19. A method according to claim 1, wherein the mobile stations are located in at least one of the same location area and different location areas.

20. A method according to claim 1, wherein a copy of the subscriber data of the at least one mobile stations of the first network stored in the home location register of the first network is sent to the switching means of the second network.

21. A method according to claim 1, wherein when a mobile station of the first network is in an idle state when registered in the second network, the mobile station performs repeated re-registering requests to said first switching means.

22. A method according to claim 1, wherein after a mobile station has been registered in the second network, said switching means of the second network determines allowable location areas in the second network to which the mobile station is allowed to roam in the second network.

23. A method according to claim 1, wherein several second networks are provided and said first switching means scans said several second networks if a second network has refused to take over the mobile stations during said predetermined operation condition.

24. A method according to claim 1, wherein when it is detected that the predetermined operation condition has ended in the first network, said switching means of the first network sends a stop message to the switching means of the second network, wherein said second switching means withdraws the access granting of said at least one mobile stations of the first network, whereafter said at least one mobile stations re-register in the first network.

25. A method according to claim 24, wherein the mobile stations re-register at the same switching means from which they have left the first network depending on the location of the mobile station.

26. A method according to claim 24, wherein when the mobile stations re-register at the switching means of the first network, an update location information message is sent to a home location register of the first network and the location information contained therein is compared with the location information stored when the mobile station was registered in the second network.

27. A method according to claim 1, wherein the mobile station is transferred to another second network if an overload occurs in the second network to which the mobile station has first been transferred.

2. A method for temporarily transferring one or more mobile stations of a first mobile radio communication network at predetermined operation conditions to at least one second mobile radio communication network, comprising the following steps:

a) detecting a predetermined operation condition in the first network;

b) sending, from a switching means of the first network to at least one switching means of the second, network at least one request message requesting that one or more mobile stations of said first network be handled by the second network when said predetermined operation condition is detected, the at least one request message indicating the number of mobile stations to be handled by the second network;

c) receiving a response message by the switching means of first network from the switching means of the second network indicating that the second network grants access to said one or more mobile stations of the first network; and

d) registering said one or more mobile stations of the first network in the at least one second network.

28. Telecommunication system comprising a first and at least one second mobile radio communication network, wherein at least one mobile stations of the first network are temporarily granted access in the second network at predetermined operation conditions in the first network, comprising:

in the first network;

a) an operation condition detection means detecting an predetermined operation condition in the first network;

b) a first switching means including request means for sending to a second switching means of said second network a request message requesting that one or more mobile stations of the first network be handled by the second network when said predetermined operation condition is detected, the request message indicating the number of mobile stations to be handled by the second network; and

in the at least one second network;

c) a reception means for receiving said request message from said first switching means;

d) an access grant means for determining whether the second network has enough capacity to handle calls of the at least one mobile stations when said predetermined operation condition is detected and for granting access for the mobile stations if there is enough capacity;

e) a response message sending means for sending a response message to said first switching means indicating that the second network grants access to at least one mobile stations of the first network if said access grant means determines that the capacity is sufficient; and

in at least one of the first- and second network;

f) a registering means for registering the at least one mobile stations when said predetermined operation condition is detected in the second network.

29. A system according to claim 28, wherein said request message indicates at least one access class of mobile stations to be handled by the second network.

30. A method according to claim 28, wherein

said operation condition detection means detects as said predetermined operation condition an overload condition in the first network.

31. A system according to claim 30, wherein said request message indicates at least one mobile stations of the first network which cannot be handled in said first network due to said overload condition, said response message indicates that the second network grants an access to the at least one mobile stations of the first network which cannot be handled during said overload condition and the at least one mobile stations which cannot be handled in the first network are registered in said second network.

32. A system according to claim 31, wherein said first switching means comprises a reception means for receiving said response message from said second switching means and for sending an overload message to the base station controllers connected to the first switching means of the first network indicating that a roaming to the second network is allowed for at least one mobile stations which cannot be handled in the first network due to said overload condition, said base station controllers providing said overload message to the mobile stations indicated therein.

33. A system according to claim 32, wherein said overload message lists the at least one access class for which a roaming to said second network is allowed, said base station controllers providing said overload message to the mobile stations belonging to the indicated access class.

34. A system according to claim 32, wherein said overload message indicates at least one of said at least one second network to which the mobile stations are allowed to roam and a particular switching means of said at least one second networks.

35. A system according to claim 30, wherein said request message indicates information about the overload area in the first network.

36. A system according to claim 30, wherein when said operation condition detection means detects that said overload condition has ended in the first network, said first switching means sends a stop message to said second switching means, wherein said second switching means withdraws the access granting of said at least one mobile stations of the first network.

37. A system according to claim 28, wherein said operation condition detection means detects as said predetermined operation condition at least one of a maintenance condition and a switching command by at least one mobile users in said first network.

38. A system according to claim 28, wherein said request means sends said request message to at least two switching means of the second network.

39. A system according to claim 38, wherein said request means sends several request messages separately to several switching means an the second network each request message containing a number of mobile stations of a particular access group.

40. A system according to claim 28, wherein said telecommunication system comprises several second networks and said request means sends said request message to at least one switching means in each second network.

41. A system according to claim 28, wherein said telecommunication system comprises several second networks and said switching means of said first network determines on the basis of the access classes of the mobile stations in which second network at least one of said mobile stations which cannot be handled in the first network should be registered.

42. A system according to claim 28, wherein the mobile stations in the first network are located in at least one of the same location area and different location areas.

43. A system according to claim 28, wherein said registering means copies in response to receiving a registration message from the at least one mobile stations which have been granted an access in the second network, the subscriber data of the mobile stations from the home location register of the first network into said second switching means.

44. A system according to claim 28, wherein when a mobile station of the first network is in an idle state when registered in the second network, the mobile station is adapted for performing repeated re-registering requests to said first switching means.

45. A system according to claim 28, wherein said second switching means comprises a location area determining means for determining allowable location areas in the second network where said at least one mobile stations are allowed to roam in the second network.

46. A system according to claim 28, wherein when a mobile station, which has been registered in the second network, moves outside said allowable location area, said second switching means is adapted to either continue a call, or to perform an inter-network handover to the first network or to yet another second network, or to release the call.

47. A system according to claim 28, wherein the telecommunication system comprises several several second networks and said first switching means comprises scan means for scanning the several second networks if a second network has refused to take over the mobile stations during said predetermined operation condition.

50. An exchange according to claim 40, wherein

said operation condition detection means detects as the predetermined operation condition an overload condition in the first network.

51. An exchange. according to claim 50, wherein said request message indicates at least one mobile stations of the first network which cannot be handled in the first network due to said overload condition, said response message indicates that the second network grants an access to the at least one mobile stations of the first network which cannot be handled during said overload condition and said at least one mobile stations which cannot be handled in the first network are registered in the second network.

52. An exchange according to claim 51, wherein said switching means is adapted for sending an overload message to the base station controllers of the first network indicating that a roaming to the second network is allowed for at least one mobile stations which cannot be handled in the first network due to said overload condition, said base station controllers providing said overload message to the mobile stations indicated therein.

53. An exchange according to claim 52, wherein said overload message lists the at least one access class for which a roaming to said second network is allowed, said base station controllers providing said overload message to the mobile stations belonging to the indicated access class.

54. An exchange according to claim 50, wherein when said operation condition detection means detects that said overload condition has ended in the first network, said switching means of the first network sends a stop message to said switching means of the second.network for cancelling said access grant of said at least one mobile stations.

57. An exchange according to claim 51, wherein said request message sent by said request means indicates information about the overload area in the first network.

48. An exchange of a first mobile radio communication network for handing over at least one mobile stations of a first network to at least one second mobile radio communication network at predetermined operation conditions in the first network, comprising

a) an operation condition detection means detecting a predetermined operation condition in the first network;

b) a switching means including request means for sending to a switching means of the second network a request message requesting that at least one mobile stations of the first network be handled by the second network when the predetermined operation condition is detected, the request message indicating the number of mobile stations to be;

handled by the second network;

c) a reception means for receiving a response message from a switching means of the second network indicating that the second network grants access to at least one mobile stations of the;

first network when the predetermined operation condition is detected; and

d) a registering means for registering said at least one mobile stations in the second network.

49. An exchange according to claim 48, wherein said request message indicates at least one access class of mobile stations to be handled by the second network.

55. An exchange according to claim 48, wherein said operation condition detection means detects as the predetermined operation condition at least one of a maintenance condition and a switching command by at least one mobile users in the first network.

56. An exchange according to claim 48, wherein said registering means copies, when said at least one mobile stations sends a registration message to said switching means of the second network, the subscriber data from the home location register of the first network to said switching means of the second network.

58. An exchange according to claim 48, wherein several second networks, wherein said switching means of the first network determines on the basis of the access classes of the mobile stations in which second network at least one of the mobile stations should be registered, when the predetermined operation condition is detected.

59. A telecommunication system comprising at least two mobile radio communication networks, wherein one or more mobile stations which cannot be handled in one network are handed over to another network during predetermined operation conditions in the one network, wherein at least one network comprises one or more exchanges, wherein at least one of the exchanges includes:

a) an operation condition detection means detecting a predetermined operation condition in the first network;

b) a switching means including request means for sending to a switching means of the second network a request message requesting that one or more mobile stations of the first network be handled by the second network when the predetermined operation condition is detected, the request message indicating the number of mobile stations to be handled by the second network;

c) a reception means for receiving a response message from a switching means of the second network indicating that the second network grants access to one or more mobile stations of the first network when the predetermined operation condition is detected; and

d) a registering means for registering said one or more mobile stations in the second network.

60. An exchange according to claim 59, wherein said request message indicates at least one access class of mobile stations to be handled by the second network.

61. An exchange according to claim 59, wherein said operation condition detection means detects as the predetermined operation condition an overload condition in the first network.

62. An exchange according to claim 61, wherein said request message indicates at least one mobile stations of the first network which cannot be handled in the first network due to said overload condition, said response message indicates that the second network grants an access to the at least one mobile stations of the first network which cannot be handled during said overload condition and said at least one mobile stations which cannot be handled in the first network are registered in the second network.

63. An exchange according to claim 62, wherein said switching means is adapted for sending an overload message to the base station controllers of the first network indicating that a roaming to the second network is allowed for at least one mobile stations which cannot be handled in the first network due to said overload condition, said base station controllers providing said overload message to the mobile stations indicated therein.

64. An exchange according to claim 63, wherein said overload message lists the at least one access class for which a roaming to said second network is allowed, said base station controllers providing said overload message to the mobile stations belonging to the indicated access class.

65. An exchange according to claim 62, wherein said request message sent by said request means indicates information about the overload area in the first network.

66. An exchange according to claim 61, wherein when said operation condition detection means detects that said overload condition has ended in the first network, said switching means of the first network sends a stop message to said switching means of the second network for cancelling said access grant of said at least one mobile stations.

67. An exchange according to claim 59, wherein said operation condition detection means detects as the predetermined operation condition at least one of a maintenance condition and a switching command by at least one mobile users in the first network.

68. An exchange according to claim 59, wherein said registering means copies, when said at least one mobile stations sends a registration message to said switching means of the second network, the subscriber data from the home location register of the first network to said switching means of the second network.

69. An exchange according to claim 59, wherein several second networks, wherein said switching means of the first network determines on the basis of the access classes of the mobile stations in which second network at least one of the mobile stations should be registered, when the predetermined operation condition is detected.

70. A method for temporarily transferring at least one mobile stations of a first mobile radio communication network at overload conditions to at least one second mobile radio communication network, comprising the following steps:

a) detecting an overload condition in the first network;

b) sending, from a switching means of the first network to at least one switching means of the second network, at least one request message requesting that one or more mobile stations of the first network which cannot be handled in the first network due to said overload condition be handled by the second network, the at least one request message indicating the number of mobile stations to be handled by the second network;

c) receiving a response message by the switching means of the first network from the switching means of the second network indicating that the second network grants access to one or more mobile stations of the first network which cannot be handled during said overload conditions; and

d) registering said one or more mobile stations, which cannot be handled in the first network, in the at least one second network.

71. An exchange of a first mobile radio communication network for handing over one or more mobile stations of a first network to at least one second mobile radio communication network at overload conditions in the first network, comprising

a) an overload detection means detecting an overload condition in the first network;

b) a switching means including request means for sending to a switching means of the second network a request message requesting that one or more mobile stations of the first network which cannot be handled in the first network due to said overload condition be handled by the second network, the request message indicating the number of mobile stations to be handled by the second network;

c) a reception. means for receiving a response message from a switching means of the second network indicating that the second network grants access to one or more mobile stations of the first network which cannot be handled during said overload conditions; and

d) a registering means for registering the one or more mobile stations, which cannot be handled in the first network, in the second network.