MOBILE COMMUNICATION SYSTEM, HANDOVER CONTROL METHOD, RADIO BASE STATION, AND MOBILE STATION

• US 20080153495A1
• Filed: 11/21/2007
• Published: 06/26/2008
• Est. Priority Date: 12/20/2006
• Status: Active Grant

• Current Assignee: NEC Corporation
• Original Assignee: NEC Corporation
• Inventors: Ogami, Tadashi, Hayashi, Sadafuku, Mustapha, Mazlyn Mona
• Granted Patent: US 9,730,130 B2
• Time in Patent Office: Days
• US Class Current: 455/436
• CPC Class Codes: H04W 36/30 by measured or perceived connection quality data
• CPC Class Codes: H04W 36/38 by fixed network equipment

Abstract

A mobile communication system according to an exemplary aspect of the invention is a mobile communication system including a mobile station, a radio base station as a handover source of the mobile station, and a radio base station as a handover target of the mobile station, wherein the mobile station includes a transmission unit for transmitting radio quality information between the mobile station and the radio base station as the handover target to the radio base station as the handover source; and the radio base station as the handover source includes a transmission unit for transmitting the radio quality information to the radio base station as the handover target.

Claims

1. A mobile communication system comprising a mobile station, a radio base station as a handover source of the mobile station, and a radio base station as a handover target of the mobile station, wherein

the mobile station comprises a first transmission unit for transmitting radio quality information between the mobile station and the radio base station as the handover target to the radio base station as the handover source,

the radio base station as the handover source comprises a second transmission unit for transmitting the radio quality information to the radio base station as the handover target when the mobile station is handed over from the radio base station as the handover source to the radio base station as the handover target, and

the radio base station as the handover target comprises a reception unit for receiving the radio quality information from the radio base station as the handover source, and a channel allocation unit for allocating a channel to the mobile station in accordance with the radio quality information.

2. The mobile communication system according to claim 1, wherein

the first transmission unit periodically transmits the radio quality information, and

the second transmission unit transmits the radio quality information which is accumulated by being periodically received from the mobile station to the radio base station as the handover target.

3. The mobile communication system according to claim 1, wherein the radio base station as the handover source comprises a unit for requesting from the mobile station measurement of higher accuracy than the measurement of the radio quality information at the time of the handover, and the second transmission unit transmits radio quality information between the mobile station and the radio base station as the handover target which is based on the measurement of higher accuracy than the measurement of the radio quality information to the radio base station as the handover target.

4. The mobile communication system according to claim 1, wherein the radio base station as the handover source comprises a unit for requesting from the mobile station measurement of higher accuracy than the measurement of the radio quality information before deciding the handover, and the second transmission unit transmits radio quality information between the mobile station and the radio base station as the handover target which is based on the measurement of higher accuracy than the measurement of the radio quality information to the radio base station as the handover target at the time of the handover.

5. A handover control method for a mobile communication system that comprises a mobile station, a radio base station as a handover source of the mobile station, and a radio base station as a handover target of the mobile station, the method comprising:

transmitting radio quality information between the mobile station and the radio base station as the handover target from the mobile station to the radio base station as the handover source;

transmitting the radio quality information from the radio base station as the handover source to the radio base station as the handover target when the mobile station is handed over from the radio base station as the handover source to the radio base station as the handover target;

receiving the radio quality information from the radio base station as the handover source at the radio base station as the handover target; and

allocating a channel to the mobile station at the radio base station as the handover target in accordance with the radio quality information.

6. The handover control method according to claim 5, wherein

the mobile station periodically transmits the radio quality information to the radio base station as the handover source;

and

the radio base station as the handover source transmits the radio quality information which is accumulated by being periodically received from the mobile station to the radio base station as the handover target.

7. The handover control method according to claim 5, comprising

requesting from the mobile station measurement of higher accuracy than the measurement of the radio quality information at the time of the handover, wherein

the radio base station as the handover source transmits radio quality information between the mobile station and the radio base station as the handover target which is based on the measurement of higher accuracy than the measurement of the radio quality information to the radio base station as the handover target.

8. The handover control method according to claim 5, comprising

requesting from the mobile station measurement of higher accuracy than the measurement of the radio quality information before deciding the handover at the radio base station as the handover source, wherein

the radio base station as the handover source transmits radio quality information between the mobile station and the radio base station as the handover target which is based on the measurement of higher accuracy than the measurement of the radio quality information to the radio base station as the handover target at the time of the handover.

9. A radio base station as a handover target of a mobile station, the radio base station comprising:

a reception unit for receiving radio quality information between the mobile station and the radio base station as the handover target which is measured by the mobile station from a radio base station as a handover source of the mobile station when the mobile station is handed over from the radio base station as the handover source to the radio base station as the handover target; and

a channel allocation unit for allocating a channel to the mobile station in accordance with the received radio quality information.

10. The radio base station according to claim 9, wherein the reception unit receives radio quality information between the mobile station and the radio base station as the handover target which is accumulated at the radio base station as the handover source by being periodically measured by the mobile station from the radio base station as the handover source.

11. The radio base station according to claim 9, wherein the reception unit receives, from the radio base station as the handover source, radio quality information between the mobile station and the radio base station as the handover target which is measured by the mobile station in response to the radio base station as the handover source requesting from the mobile station measurement of higher accuracy than the measurement of the radio quality information at the time of the handover.

12. The radio base station according to claim 9, wherein the reception unit receives, from the radio base station as the handover source and at the time of the handover, radio quality information between the mobile station and the radio base station as the handover target which is measured by the mobile station in response to the radio base station as the handover source requesting from the mobile station measurement of higher accuracy than the measurement of the radio quality information before the handover is decided.

13. A recording medium having recorded thereon a program for causing a computer to execute an operation control method for a radio base station as a handover target of a mobile station, the program comprising:

processing for receiving radio quality information between the mobile station and the radio base station as the handover target which is measured by the mobile station from a radio base station as a handover source of the mobile station when the mobile station is handed over from the radio base station as the handover source to the radio base station as the handover target; and

processing for allocating a channel to the mobile station in accordance with the received radio quality information.

14. A mobile station in a mobile communication system in which the mobile station performs measurement of radio quality information between the mobile station and a radio base station as a handover target and transmits the radio quality information to a radio base station as a handover source, the radio base station as the handover source transmits the radio quality information to the radio base station as the handover target when the mobile station is handed over from the radio base station as the handover source to the radio base station as the handover target, and the radio base station as the handover target allocates a channel to the mobile station in accordance with the radio quality information received from the radio base station as the handover source,

the mobile station comprising a unit for performing measurement of higher accuracy than the measurement and transmitting the result of measurement to the radio base station as the handover source in response to a request from the radio base station as the handover source to the mobile station for measurement of higher accuracy than the measurement.

15. A recording medium having recorded thereon a program for causing a computer to execute an operation control method for a mobile station in a mobile communication system in which the mobile station performs measurement of radio quality information between the mobile station and a radio base station as a handover target and transmits the radio quality information to a radio base station as a handover source, the radio base station as the handover source transmits the radio quality information to the radio base station as the handover target when the mobile station is handed over from the radio base station as the handover source to the radio base station as the handover target, and the radio base station as the handover target allocates a channel to the mobile station in accordance with the radio quality information received from the radio base station as the handover source, the program comprising:

processing for performing measurement of higher accuracy than the measurement and transmitting the result of measurement to the radio base station as the handover source in response to a request from the radio base station as the handover source to the mobile station for measurement of higher accuracy than the measurement.

16. A mobile communication system comprising a mobile station, a radio base station as a handover source of the mobile station, and a radio base station as a handover target of the mobile station, wherein

the mobile station comprises a first transmission unit for transmitting radio quality information between the mobile station and the radio base station as the handover target to the radio base station as the handover source;

the radio base station as the handover source comprises a second transmission unit for transmitting the radio quality information to the radio base station as the handover target before transmitting context information necessary for communication with the mobile station to the radio base station as the handover target; and

the radio base station as the handover target comprises a reception unit for receiving the radio quality information from the radio base station as the handover source, and a determination unit for determining whether it is possible to accept a handover of the mobile station based on the radio quality information.

17. The mobile communication system according to claim 16, wherein the radio base station as the handover source stops transmission of the context information to the radio base station as the handover target when the determination unit determines that it is impossible to accept the handover.

18. The mobile communication system according to claim 16, wherein the radio base station as the handover source transmits the context information to the radio base station as the handover target when the determination unit determines that it is possible to accept the handover.

23. The mobile communication system according to claim 16, wherein each radio base station informs other radio base stations in advance whether the radio base station performs determination of whether it is possible to accept the handover in response to transfer of radio quality information between the mobile station and the radio base station.

19. A mobile communication system comprising a mobile station, a radio base station as a handover source of the mobile station, and candidate radio base stations for a handover target of the mobile station, wherein

the mobile station comprises a first transmission unit for transmitting radio quality information between the mobile station and the candidate radio base stations to the radio base station as the handover source;

the radio base station as the handover source comprises a second transmission unit for transmitting the radio quality information to the candidate radio base stations before deciding a handover of the mobile station from the radio base station as the handover source to any of the candidate radio base stations; and

the candidate radio base stations each comprise a reception unit for receiving the radio quality information from the radio base station as the handover source, a determination unit for determining whether it is possible to accept the handover or not based on the radio quality information, and a third transmission unit for transmitting the result of the determination to the radio base station as the handover source.

20. The mobile communication system according to claim 19, wherein the radio base station as the handover source decides the handover by selecting a radio base station as the handover target of the mobile station based on the radio quality information from among the candidate radio base stations that have determined it is possible to accept the handover.

21. The mobile communication system according to claim 19, wherein

the first transmission unit periodically transmits the radio quality information;

the second transmission unit transmits the radio quality information to the candidate radio base stations every time the radio quality information is received from the mobile station;

the determination unit determines whether it is possible to accept the handover or not based on the radio quality information every time the radio quality information is received from the radio base station as the handover source; and

the third transmission unit transmits the result of the determination to the radio base station as the handover source every time the determination unit determines whether it is possible to accept the handover or not.

22. The mobile communication system according to claim 19, wherein the second transmission unit transmits the radio quality information to the candidate radio base stations when available radio resource of the radio base station as the handover source has fallen below a predetermined threshold value.

24. A handover control method for a mobile communication system that comprises a mobile station, a radio base station as a handover source of the mobile station, and a radio base station as a handover target of the mobile station, the method comprising:

transmitting radio quality information between the mobile station and the radio base station as the handover target from the mobile station to the radio base station as the handover source;

transmitting the radio quality information from the radio base station as the handover source to the radio base station as the handover target before transmitting context information necessary for communication with the mobile station to the radio base station as the handover target;

receiving the radio quality information at the radio base station as the handover target from the radio base station as the handover source; and

determining whether it is possible to accept a handover of the mobile station at the radio base station as the handover target based on the radio quality information.

25. The handover control method according to claim 24, comprising:

stopping transmission of the context information from the radio base station as the handover source to the radio base station as the handover target when the radio base station as the handover target determines that it is impossible to accept the handover.

26. The handover control method according to claim 24, comprising:

transmitting the context information from the radio base station as the handover source to the radio base station as the handover target when the radio base station as the handover target determines that it is possible to accept the handover.

31. The handover control method according to claim 24, wherein each radio base station informs other radio base stations in advance whether the radio base station performs determination of whether it is possible to accept the handover in response to transfer of radio quality information between the mobile station and the radio base station.

27. A handover control method for a mobile communication system that comprises a mobile station, a radio base station as a handover source of the mobile station, and candidate radio base stations for a handover target of the mobile station, the method comprising:

transmitting radio quality information between the mobile station and the candidate radio base stations from the mobile station to the radio base station as the handover source;

transmitting the radio quality information from the radio base station as the handover source to the candidate radio base stations before deciding a handover of the mobile station from the radio base station as the handover source to any of the candidate radio base stations;

receiving the radio quality information from the radio base station as the handover source at the candidate radio base stations;

determining whether it is possible to accept the handover or not based on the radio quality information at the candidate radio base stations; and

transmitting the result of the determination from the candidate radio base stations to the radio base station as the handover source.

28. The handover control method according to claim 27, wherein the radio base station as the handover source decides the handover by selecting a radio base station as the handover target of the mobile station based on the radio quality information from among the candidate radio stations that have determined it is possible to accept the handover.

29. The handover control method according to claim 27, wherein

the mobile station periodically transmits the radio quality information;

the radio base station as the handover source transmits the radio quality information to the candidate radio base stations every time the radio quality information is received from the mobile station; and

each of the candidate radio base stations determines whether it is possible to accept the handover or not based on the radio quality information every time the radio quality information is received from the radio base station as the handover source, and transmits the result of the determination to the radio base station as the handover source every time the candidate radio base station determines whether it is possible to accept the handover or not.

30. The handover control method according to claim 27, wherein the radio base station as the handover source transmits the radio quality information to the candidate radio base stations when available radio resource of the radio base station as the handover source has fallen below a predetermined threshold value.

32. A radio base station as a handover target of a mobile station, the radio base station comprising:

a reception unit for receiving radio quality information between the mobile station and the radio base station as the handover target which is measured by the mobile station from a radio base station as a handover source of the mobile station before receiving context information necessary for communication with the mobile station; and

a determination unit for determining whether it is possible to accept a handover of the mobile station or not based on the radio quality information.

33. The radio base station as the handover target according to claim 32, wherein the reception unit receives the context information transmitted from the radio base station as the handover source when the determination unit determines it is possible to accept the handover.

34. A radio base station as a handover source of a mobile station, the radio base station comprising:

a unit for receiving radio quality information between the mobile station and a radio base station as a handover target of the mobile station which is measured by the mobile station; and

a transmission unit for transmitting the radio quality information to the radio base station as the handover target before transmitting context information necessary for communication with the mobile station to the radio base station as the handover target, wherein

the radio quality information is used for determining whether the radio base station as the handover target can accept the handover of the mobile station or not.

35. The radio base station as the handover source according to claim 34, wherein the transmission unit stops transmission of the context information to the radio base station as the handover target when the radio base station as the handover target determines that it is impossible to accept the handover.

36. The radio base station as the handover source according to claim 34, wherein the transmission unit transmits the context information to the radio base station as the handover target when the radio base station as the handover target determines that it is possible to accept the handover.

37. A candidate radio base station for a handover target of a mobile station, the candidate radio base station comprising:

a reception unit for receiving radio quality information between the mobile station and the candidate radio base station which is measured by the mobile station from a radio base station as a handover source of the mobile station before decision of a handover of the mobile station from the radio base station as the handover source to the candidate radio base station;

a determination unit for determining whether it is possible to accept the handover or not based on the radio quality information; and

a transmission unit for transmitting the result of the determination to the radio base station as the handover source.

38. The candidate radio base station according to claim 37, wherein

the reception unit receives via the radio base station as the handover source the radio quality information periodically transmitted from the mobile station;

the determination unit determines whether it is possible to accept the handover or not based on the radio quality information every time the radio quality information is received; and

the transmission unit transmits the result of the determination to the radio base station as the handover source every time the determination unit determines whether it is possible to accept the handover or not.

39. The candidate radio base station according to claim 37, wherein the candidate radio base station informs other radio base stations in advance whether the candidate radio base station performs determination of whether it is possible to accept the handover or not.

40. A radio base station as a handover source of a mobile station, the radio base station comprising:

a reception unit for receiving radio quality information between the mobile station and candidate radio base stations for a handover target of the mobile station which is measured by the mobile station; and

a transmission unit for transmitting the radio quality information to the candidate radio base stations before deciding a handover of the mobile station from the radio base station as the handover source to any of the candidate radio base stations, wherein

the radio quality information is used for determining whether the candidate radio base stations can accept the handover of the mobile station or not.

41. The radio base station as the handover source according to claim 40, comprising a decision unit for deciding the handover by selecting a radio base station as the handover target of the mobile station based on the radio quality information from among the candidate radio base stations that have determined it is possible to accept the handover.

42. The radio base station as the handover source according to claim 40, wherein

the reception unit periodically receives the radio quality information from the mobile station;

and

the transmission unit transmits the radio quality information to the candidate radio base stations every time the radio quality information is received from the mobile station.

43. The radio base station as the handover source according to claim 40, wherein the transmission unit transmits the radio quality information to the candidate radio base stations when available radio resource of the radio base station as the handover source has fallen below a predetermined threshold value.

44. A recording medium having recorded thereon a program for causing a computer to execute an operation control method for a radio base station as a handover target of a mobile station, the program comprising:

processing for receiving radio quality information between the mobile station and the radio base station as the handover target which is measured by the mobile station from a radio base station as a handover source of the mobile station before receiving context information necessary for communication with the mobile station; and

processing for determining whether it is possible to accept a handover of the mobile station or not based on the radio quality information.

45. A recording medium having recorded thereon a program for causing a computer to execute an operation control method for a radio base station as a handover source of a mobile station, the program comprising:

processing for receiving radio quality information between the mobile station and a radio base station as a handover target of the mobile station which is measured by the mobile station; and

processing for transmitting the received radio quality information, which will be used for determining whether the radio base station as the handover target can accept the handover of the mobile station or not, to the radio base station as the handover target before transmitting context information necessary for communication with the mobile station to the radio base station as the handover target.

46. A recording medium having recorded thereon a program for causing a computer to execute an operation control method for a candidate radio base station for a handover target of a mobile station, the program comprising:

processing for receiving radio quality information between the mobile station and the candidate radio base station which is measured by the mobile station from a radio base station as a handover source of the mobile station before decision of a handover of the mobile station from the radio base station as the handover source to the candidate radio base station;

processing for determining whether it is possible to accept the handover or not based on the radio quality information; and

processing for transmitting the result of the determination to the radio base station as the handover source.

47. A recording medium having recorded thereon a program for causing a computer to execute an operation control method for a radio base station as a handover source of a mobile station, the program comprising:

processing for receiving radio quality information between the mobile station and a candidate radio base station for a handover target of the mobile station which is measured by the mobile station; and

processing for transmitting the received radio quality information, which will be used for determining whether the candidate radio base station can accept the handover, to the candidate radio base station before deciding a handover of the mobile station from the radio base station as the handover source to the candidate radio base station.

48. A mobile communication system comprising a mobile station, a radio base station as a handover source of the mobile station, a radio base station as a handover target of the mobile station, a first radio base station controller for controlling the radio base station as the handover source, and a second radio base station controller for controlling the radio base station as the handover target, wherein

the mobile station comprises a transmission unit for transmitting radio quality information between the mobile station and the radio base station as the handover target to the first radio base station controller via the radio base station as the handover source;

the first radio base station controller comprises a transmission unit for transmitting the radio quality information to the second radio base station controller before transmitting context information necessary for communication with the mobile station to the radio base station as the handover target;

the second radio base station controller comprises a reception unit for receiving the radio quality information from the first radio base station controller, and a determination unit for determining whether it is possible to accept a handover of the mobile station based on the radio quality information.

49. A mobile communication system comprising a mobile station, a radio base station as a handover source of the mobile station, a candidate radio base station for a handover target of the mobile station, a first radio base station controller for controlling the radio base station as the handover source, and a second radio base station controller for controlling the candidate radio base station, wherein

the mobile station comprises a transmission unit for transmitting radio quality information between the mobile station and the candidate radio base station to the first radio base station controller via the radio base station as the handover source;

the first radio base station controller comprises a transmission unit for transmitting the radio quality information to the second radio base station controller before deciding a handover of the mobile station from the radio base station as the handover source to the candidate radio base station; and

the second radio base station controller comprises a reception unit for receiving the radio quality information from the first radio base station controller, and a determination unit for determining whether it is possible to accept the handover based on the radio quality information.