Radio communication system, base station device, mobile terminal device, and radio link switching method

• US 20050164706A1
• Filed: 06/05/2002
• Published: 07/28/2005
• Est. Priority Date: 06/05/2002
• Status: Active Grant

• Current Assignee: Mitsubishi Denki Kabushiki Kaisha (Mitsubishi Electric Corporation)
• Original Assignee: Mitsubishi Denki Kabushiki Kaisha (Mitsubishi Electric Corporation)
• Inventors: Wakabayashi, Hideji
• Granted Patent: US 7,082,304 B2
• Time in Patent Office: Days
• US Class Current: 455/441
• CPC Class Codes: H04W 36/08 Reselecting an access point
• CPC Class Codes: H04W 36/18 for allowing seamless reselection, e.g. soft reselection
• CPC Class Codes: H04W 36/324 by mobility data, e.g. speed data
• CPC Class Codes: H04W 76/20 Manipulation of established connections

Abstract

A terminal 100 detects a moving speed of the terminal 100 and discriminates if it is necessary to switch a radio link between a radio link 102 without soft handover and a radio link 103 with soft handover, when it is necessary to switch the radio link, a request to switch states with/without soft handover 106 is sent to a base station 101, the base station 101 switches the states with/without soft handover based on the request to switch states with/without soft handover 106, in addition, an instruction to switch states with/without soft handover 107 is sent to the terminal 100, and the terminal 100 switches the states with/without soft handover based on the instruction to switch states with/without soft handover 107.

Claims

1. A radio communication system in which a plurality of radio links are provided and which includes a base station device and a mobile terminal device conducting data communication using one of the plurality of radio links,

wherein the base station device and the mobile terminal device carry out switching a radio link used for the data communication based on a moving speed of the mobile terminal device.

2. The radio communication system of claim 1,

wherein the mobile terminal device

detects a moving speed of the mobile terminal device itself,

discriminates if it is necessary to switch from the radio link which is currently used to another radio link based on the moving speed detected of the mobile terminal device itself,

sends a switching request to switch the radio link which is currently used to another radio link when it is necessary to switch to another radio link,

wherein the base station device

when the switching request is received from the mobile terminal device, switches the radio link used for the data communication from the radio link which is currently used to another radio link, and sends a switching instruction to switch the radio link used for the data communication to the mobile terminal device, and

wherein the mobile terminal device

when the switching instruction is received from the base station device, switches the radio link used for the data communication from the radio link which is currently used to another radio link.

3. The radio communication system of claim 2,

wherein a radio link adaptive to soft handover which is adaptive to soft handover and a radio link nonadaptive to soft handover which is nonadaptive to soft handover are provided between the base station device and the mobile terminal device as the plurality of radio links,

wherein the mobile terminal device

checks if the moving speed detected of the mobile terminal device itself is equal to or greater than a predetermined threshold value or not, and discriminates whether the radio link which is currently used is the radio link adaptive to soft handover or the radio link nonadaptive to soft handover;

when the moving speed detected of the mobile terminal device itself is equal to or greater than the predetermined threshold value and the radio link which is currently used is the radio link nonadaptive to soft handover, sends a switching request to radio link adaptive to soft handover to request to switch to the radio link adaptive to soft handover from the radio link nonadaptive to soft handover to the base station device; and

when the moving speed detected of the mobile terminal device itself is less than the predetermined threshold value and the radio link which is currently used is the radio link adaptive to soft handover, sends a switching request to radio link nonadaptive to soft handover to request to switch to the radio link nonadaptive to soft handover from the radio link adaptive to soft handover to the base station device,

wherein the base station device

when the switching request to radio link adaptive to soft handover is received from the mobile terminal device, switches the radio link used for the data communication from the radio link nonadaptive to soft handover to the radio link adaptive to soft handover, and sends a switching instruction to radio link adaptive to soft handover to instruct to switch the radio link used for the data communication from the radio link nonadaptive to soft handover to the radio link adaptive to soft handover to the mobile terminal device; and

when the switching request to radio link nonadaptive to soft handover is received from the mobile terminal device, switches the radio link used for the data communication from the radio link adaptive to soft handover to the radio link nonadaptive to soft handover, and sends a switching instruction to radio link nonadaptive to soft handover to instruct to switch the radio link used for the data communication from the radio link adaptive to soft handover to the radio link nonadaptive to soft handover to the mobile terminal device,

wherein the mobile terminal device

when the switching request to radio link adaptive to soft handover is received from the base station device, switches the radio link used for the data communication from the radio link nonadaptive to soft handover to the radio link adaptive to soft handover; and

when the switching request to radio link nonadaptive to soft handover is received from the base station device, switches the radio link used for the data communication from the radio link adaptive to soft handover to the radio link nonadaptive to soft handover.

4. The radio communication system of claim 1,

wherein the mobile terminal device

detects the moving speed of the mobile terminal device itself, and sends moving speed information showing the moving speed detected of the mobile terminal device to the base station device,

wherein the base station device

receives the moving speed information from the mobile terminal device;

discriminates if it is necessary to switch from the radio link which is currently used to another radio link based on the moving speed of the mobile terminal device shown in the moving speed information received; and

when it is necessary to switch to another radio link, switches the radio link used for the data communication from the radio link which is currently used to another radio link, and sends a switching instruction to instruct to switch the radio link used for the data communication to the mobile terminal device,

wherein the mobile terminal device

when the switching instruction is received from the base station, switches the radio link used for the data communication from the radio link which is currently used to another radio link.

5. The radio communication system of claim 4,

wherein a radio link adaptive to soft handover which is adaptive to soft handover and a radio link nonadaptive to soft handover which is nonadaptive to soft handover are provided between the base station device and the mobile terminal device as the plurality of radio links,

wherein the base station device

when the moving speed information is received from the mobile terminal device, checks if the moving speed of the mobile terminal device shown in the moving speed information is equal to or greater than a predetermined threshold value or not, and discriminates whether the radio link which is currently used is the radio link adaptive to soft handover or the radio link nonadaptive to soft handover;

when the moving speed of the mobile terminal device is equal to or greater than the predetermined threshold value and the radio link which is currently used is the radio link nonadaptive to soft handover, switches the radio link used for the data communication from the radio link nonadaptive to soft handover to the radio link adaptive to soft handover, and sends a switching instruction to radio link adaptive to soft handover to instruct to switch the radio link used for the data communication from the radio link nonadaptive to soft handover to the radio link adaptive to soft handover to the mobile terminal device; and

when the moving speed of the mobile terminal device is less than the predetermined threshold value and the radio link which is currently used is the radio link adaptive to soft handover, switches the radio link used for the data communication from the radio link adaptive to soft handover to the radio link nonadaptive to soft handover, and sends a switching instruction to radio link nonadaptive to soft handover to instruct to switch the radio link used for the data communication from the radio link adaptive to soft handover to the radio link nonadaptive to soft handover to the mobile terminal device,

wherein the mobile terminal device

when the switching instruction to radio link adaptive to soft handover is received from the base station device, switches the radio link used for the data communication from the radio link nonadaptive to soft handover to the radio link adaptive to soft handover; and

when the switching instruction to radio link nonadaptive to soft handover is received from the base station device, switches the radio link used for the data communication from the radio link adaptive to soft handover to the radio link nonadaptive to soft handover.

6. A radio communication system in which a plurality of radio links are provided and which includes a base station device and a mobile terminal device conducting data communication using one of the plurality of radio links,

wherein the base station device and the mobile terminal device carry out switching a radio link used for the data communication based on communication quality of a radio link which is currently used.

7. The radio communication system of claim 6,

wherein the mobile terminal device

measures communication quality of the radio link which is currently used, and sends communication quality information showing the communication quality measured to the base station device,

wherein the base station device

receives the communication quality information from the mobile terminal device;

estimates a moving speed of the mobile terminal device based on the communication quality shown in the communication quality information received;

discriminates if it is necessary to switch from the radio link which is currently used to another radio link based on the moving speed estimated of the mobile terminal device; and

when it is necessary to switch to another radio link, switches the radio link used for the data communication from the radio link which is currently used to another radio link, and sends a switching instruction to instruct to switch the radio link used for the data communication to the mobile terminal device,

wherein the mobile terminal device

when the switching instruction is received from the base station device, switches the radio link used for the data communication from the radio link which is currently used to another radio link.

8. The radio communication system of claim 7,

wherein a radio link adaptive to soft handover and a radio link nonadaptive to soft handover are provided between the base station device and the mobile terminal device as the plurality of radio links,

wherein the base station device

when the moving speed of the mobile terminal device is estimated based on the communication quality shown in the communication quality information,

checks if the moving speed estimated of the mobile terminal device is equal to or greater than a predetermined threshold value or not, and discriminates whether the radio link which is currently used is the radio link adaptive to soft handover or the radio link nonadaptive to soft handover,

when the moving speed estimated is equal to or greater than the predetermined threshold value and the radio link which is currently used is the radio link nonadaptive to soft handover, switches the radio link used for the data communication from the radio link nonadaptive to soft handover to the radio link adaptive to soft handover, and sends a switching instruction to radio link adaptive to soft handover to instruct to switch the radio link used for the data communication from the radio link nonadaptive to soft handover to the radio link adaptive to soft handover to the mobile terminal device, and

when the moving speed estimated is less than the predetermined threshold value and the radio link which is currently used is the radio link adaptive to soft handover, switches the radio link used for the data communication from the radio link adaptive to soft handover to the radio link nonadaptive to soft handover, and sends a switching instruction to radio link nonadaptive to soft handover to instruct to switch the radio link used for the data communication from the radio link adaptive to soft handover to the radio link nonadaptive to soft handover to the mobile terminal device,

wherein the mobile terminal device

when the switching instruction to radio link adaptive to soft handover is received from the base station device, switches the radio link used for the data communication from the radio link nonadaptive to soft handover to the radio link adaptive to soft handover;

and

when the switching instruction to radio link nonadaptive to soft handover is received from the base station device, switches the radio link used for the data communication from the radio link adaptive to soft handover to the radio link nonadaptive to soft handover.

9. The radio communication system of claim 6,

wherein the base station device

measures the communication quality of the radio link which is currently used;

estimates a moving speed of the mobile terminal device based on measurement result;

discriminates if it is necessary to switch from the radio link which is currently used to another radio link based on the moving speed estimated of the mobile terminal device; and

when it is necessary to switch to another radio link, switches the radio link used for the data communication from the radio link which is currently used to another radio link, and sends a switching instruction to instruct to switch the radio link used for the data communication to the mobile terminal device,

wherein the mobile terminal device

when the switching instruction is received from the base station device, switches the radio link used for the data communication from the radio link which is currently used to another radio link.

10. The radio communication system of claim 9,

wherein a radio link adaptive to soft handover which is adaptive to soft handover and a radio link nonadaptive to soft handover which is nonadaptive to soft handover are provided between the base station device and the mobile terminal device as the plurality of radio links,

wherein the base station device

when the moving speed of the mobile terminal device is estimated,

checks if the moving speed estimated of the mobile terminal device is equal to or greater than a predetermined threshold value or not, and discriminates whether the radio link which is currently used is the radio link adaptive to soft handover or the radio link nonadaptive to soft handover,

when the moving speed estimated is equal to or greater than the predetermined threshold value and the radio link which is currently used is the radio link nonadaptive to soft handover, switches the radio link used for the data communication from the radio link nonadaptive to soft handover to the radio link adaptive to soft handover, and sends a switching instruction to radio link adaptive to soft handover to instruct to switch the radio link used for the data communication from the radio link nonadaptive to soft handover to the radio link adaptive to soft handover to the mobile terminal device, and

when the moving speed estimated is less than the predetermined threshold value and the radio link which is currently used is the radio link adaptive to soft handover, switches the radio link used for the data communication from the radio link adaptive to soft handover to the radio link nonadaptive to soft handover, and sends a switching instruction to radio link nonadaptive to soft handover to instruct to switch the radio link used for the data communication from the radio link adaptive to soft handover to the radio link nonadaptive to soft handover to the mobile terminal device,

wherein the mobile terminal device

when the switching instruction to radio link adaptive to soft handover is received from the base station device, switches the radio link used for the data communication from the radio link nonadaptive to soft handover to the radio link adaptive to soft handover;

and

when the switching instruction to radio link nonadaptive to soft handover is received from the base station device, switches the radio link used for the data communication from the radio link adaptive to soft handover to the radio link nonadaptive to soft handover.

11. A base station device which carries out data communication with a mobile terminal device using one of a plurality of radio links out of the plurality of radio links provided between the base station device and the mobile terminal device,

wherein the base station device switches a radio link used for the data communication with the mobile terminal device based on a moving speed of the mobile terminal device.

12. The base station device of claim 11,

wherein the mobile terminal device

detects a moving speed of the mobile terminal device itself, discriminates if it is necessary to switch from the radio link which is currently used to another radio link based on the moving speed detected of the mobile terminal device itself, and when it is necessary to switch to another radio link, is able to send a switching request to request to switch from the radio link which is currently used to another radio link to the base station device,

wherein the base station device comprises:

a communicating unit for receiving the switching request from the mobile terminal device;

a radio link switching unit for switching the radio link used for the data communication with the mobile terminal device from the radio link which is currently used to another radio link based on the switching request received by the communicating unit; and

a switching instruction generating unit for generating a switching instruction to instruct the mobile terminal device to switch the radio link used for the data communication when the radio link switching unit switches the radio link, and sending the switching instruction generated to the mobile terminal device through the communicating unit.

13. The base station device of claim 11,

wherein the mobile terminal device

detects the moving speed of the mobile terminal device itself, and is able to send moving speed information showing the moving speed detected of the mobile terminal device itself to the base station device,

wherein base station device comprises:

a communicating unit for receiving the moving speed information from the mobile terminal device;

a switching discriminating unit for discriminating if it is necessary to switch from the radio link which is currently used to another radio link based on the moving speed of the mobile terminal device shown in the moving speed information;

a radio link switching unit for switching the radio link used for the data communication with the mobile terminal device from the radio link which is currently used to another radio link when the switching discriminating unit discriminates it is necessary to switch from the radio link which is currently used to another radio link; and

a switching instruction generating unit for generating a switching instruction to instruct the mobile terminal device to switch the radio link used for the data communication, and sending the switching instruction generated to the mobile terminal device through the communicating unit.

14. A base station device which carries out data communication with a mobile terminal device using one of a plurality of radio links out of the plurality of radio links provided between the base station device and the mobile terminal device,

wherein the base station device switches a radio link used for the data communication with the mobile terminal device based on communication quality of a radio link which is currently used.

15. The base station device of claim 14,

wherein the mobile terminal device

measures the communication quality of the radio link which is currently used, and is able to send communication quality information showing the communication quality measured to the base station device,

wherein the base station device comprises:

a communicating unit for receiving the communication quality information from the mobile terminal device;

a moving speed estimating unit for estimating a moving speed of the mobile terminal device based on the communication quality shown in the communication quality information;

a switching discriminating unit for discriminating if it is necessary to switch from the radio link which is currently used to another radio link based on the moving speed estimated of the mobile terminal device estimated by the moving speed estimating unit;

a radio link switching unit for switching the radio link used for the data communication from the radio link which is currently used to another radio link when the switching discriminating unit discriminates it is necessary to switch from the radio link which is currently used to another radio link; and

a switching instruction generating unit for generating a switching instruction to instruct the mobile terminal device to switch the radio link used for the data communication when the radio link switching unit switches the radio link, and sending the switching instruction generated to the mobile terminal device through the communicating unit.

16. The base station device of claim 14,

wherein the base station device comprises:

a communication quality measuring unit for measuring the communication quality of the radio link which is currently used;

a moving speed estimating unit for estimating a moving speed of the mobile terminal device based on measurement result by the communication quality measuring unit;

a switching discriminating unit for discriminating if it is necessary to switch from the radio link which is currently used to another radio link based on the moving speed estimated of the mobile terminal device estimated by the moving speed estimating unit;

a radio link switching unit for switching the radio link used for the data communication from the radio link which is currently used to another radio link when the switching discriminating unit discriminates it is necessary to switch from the radio link which is currently used to another radio link; and

a switching instruction generating unit for generating a switching instruction to instruct the mobile terminal device to switch the radio link used for the data communication when the radio link switching unit switches the radio link, and sending the switching instruction generated to the mobile terminal device through the communicating unit.

17. A mobile terminal device which carries out data communication with a base station device using one of a plurality of radio links out of the plurality of radio links provided between the base station device and the mobile terminal device,

wherein the mobile terminal device switches a radio link used for the data communication with the base station device based on a moving speed of the mobile terminal device itself

18. The mobile terminal device of claim 17,

wherein the mobile terminal device comprises:

a moving speed detecting unit for detecting a moving speed of the mobile terminal device itself,

a switching request discriminating unit for discriminating if it is necessary to switch from a radio link which is currently used to another radio link based on the moving speed detected of the mobile terminal device itself by the moving speed detecting unit, and when it is necessary to switch to another radio link, generating a switching request to request to switch from the radio link which is currently used to another radio link;

a communicating unit for sending the switching request generated by the switching request discriminating unit to the base station device, and receiving a switching instruction to instruct to switch the radio link used for the data communication from the base station device; and

a radio link switching unit for switching the radio link used for the data communication from the radio link which is currently used to another radio link based on the switching instruction received by the communicating unit.

19. The mobile terminal device of claim 17 comprising:

a moving speed detecting unit for detecting a moving speed of the mobile terminal device itself,

a communicating unit for sending moving speed information showing the moving speed detected of the mobile terminal device itself by the moving speed detecting unit to the base station device, and in a specified case, receiving a switching instruction to instruct to switch the radio link used for the data communication from the base station device; and

a radio link switching unit for switching the radio link used for the data communication from the radio link which is currently used to another radio link based on the switching instruction received by the communicating unit.

20. A mobile terminal device which carries out data communication with a base station device using one of a plurality of radio links out of the plurality of radio links provided between the base station device and the mobile terminal device,

wherein the mobile terminal device switches a radio link used for the data communication with the base station device based on communication quality of a radio link which is currently used.

21. The mobile terminal device of claim 20 comprising:

a communication quality measuring unit for measuring communication quality of the radio link which is currently used;

a communicating unit for sending communication quality information showing the communication quality measured by the communication quality measuring unit to the base station unit, and in a specified case, receiving a switching instruction to instruct to switch the radio link used for the data communication from the base station device; and

a radio link switching unit for switching the radio link used for the data communication from the radio link which is currently used to another radio link based on the switching instruction received by the communicating unit.

22. A radio link switching method for switching a radio link used for data communication between a base station device and a mobile terminal device, the method comprising

switching the radio link used for the data communication between the base station device and the mobile terminal device based on a moving speed of the mobile terminal device.

23. A radio link switching method for switching a radio link used for data communication between a base station device and a mobile terminal device, the method comprising

switching the radio link used for the data communication between the base station device and the mobile terminal device based on communication quality of a radio link which is currently used between the base station device and the mobile terminal device.