RADIO COMMUNICATION SYSTEM, MOBILE RELAY STATION, MOBILE STATION, AND RADIO COMMUNICATION METHOD

• US 20110124330A1
• Filed: 11/19/2010
• Published: 05/26/2011
• Est. Priority Date: 11/20/2009
• Status: Active Grant

• Current Assignee: Fujitsu Limited
• Original Assignee: Fujitsu Limited
• Inventors: KOJIMA, Yuji
• Granted Patent: US 8,620,210 B2
• Time in Patent Office: Days
• US Class Current: 455/424
• CPC Class Codes: H04B 7/155 Ground-based stations H04B7/204 takes precedence
• CPC Class Codes: H04W 36/324 by mobility data, e.g. speed data
• CPC Class Codes: H04W 84/005 Moving wireless networks

Abstract

A radio communication system in which a mobile relay station includes a notification unit configured to notify the mobile station of mobility state information of the mobile relay station determined based on a number of base stations selected within a specified time, and the mobile station includes a base station selection processing unit to select the base station based on the mobility state information when the mobile station switches a device to be communicated with from the mobile relay station to the base station.

Claims

1. A radio communication system in which a mobile relay station relays radio communication between a base station and a mobile station, the radio communication system comprising:

a notification unit to notify the mobile station of mobility state information of the mobile relay station determined based on a number of base stations selected within a specified time; and

a base station selection processing unit to select a base station based on the mobility state information when the mobile station switches a device to be communicated with from the mobile relay station to the base station.

2. The radio communication system according to claim 1, wherein the mobile station further comprises:

a detection unit to detect an abnormality of the mobile relay station, and

a switching unit to switch the device to be communicated with from the mobile relay station to the base station when the abnormality is detected, and

wherein, the base station selection processing unit selects the base station based on the mobility state information when the device to be communicated with is switched to the base station.

3. The radio communication system according to claim 1, wherein the base station selection processing unit corrects, in accordance with the mobility state information, a parameter included in a specified evaluation formula for evaluating a communication quality of a cell, and selects the base station by using the specified evaluation formula including the corrected parameter.

4. The radio communication system according to claim 2, wherein the detection unit receives a parameter included in a specified evaluation formula for evaluating a communication quality of a cell, and detects an occurrence of an overload on the mobile relay station as the abnormality when an amount of change in the parameter exceeds a specified threshold value.

5. The radio communication system according to claim 2, wherein the mobile relay station further includes a reference radio wave transmission unit to transmit to the mobile station a reference radio wave which is a known radio wave used to determine a radio communication quality between the mobile relay station and the mobile station, and

wherein the detection unit measures a radio field strength of the reference radio wave transmitted from the mobile relay station, and detects an occurrence of a malfunction in the mobile relay station as the abnormality when the radio field strength falls below a specified threshold value.

6. A mobile relay station to relay radio communication between a base station and a mobile station, the mobile relay station comprising:

a notification unit to notify the mobile station, which selects the base station based on mobility state information when switching a device to be communicated with from the mobile relay station to the base station, of the mobility state information of the mobile relay station determined based on a number of base stations selected within a specified time.

7. A mobile station that performs radio communication with a base station, which is relayed by a mobile relay station, the mobile station comprising:

a base station selection processing unit to select the base station based on mobility state information notified from the mobile relay station when a device to be communicated with the mobile station is switched from the mobile relay station to the base station.

8. A radio communication method performed by a radio communication system in which a mobile relay station relays radio communication between a base station and a mobile station, the method comprising:

notifying the mobile station of mobility state information of the mobile relay station determined based on a number of base stations selected within a specified time, and

selecting the base station based on the mobility state information when switching a device to be communicated with from the mobile relay station to the base station.

9. A radio communication system to relay radio communication, the radio communication system comprising:

a mobile relay station including a notification unit to notify a mobile station of mobility state information of the mobile relay station determined based on a number of base stations selected within a specified time, and

a mobile station including a communication unit to control radio communication using the notified mobility state information.

10. The radio communication system according to claim 9, wherein the mobile station further comprises:

a detection unit to detect an abnormality of the mobile relay station;

a switching unit to switch the device to be communicated with from the mobile relay station to the base station when the abnormality is detected; and

a base station selection processing unit to select the base station based on the mobility state information when the device to be communicated with is switched to the base station.

11. The radio communication system according to claim 10, wherein the detection unit receives a parameter included in a specified evaluation formula for evaluating a communication quality of a cell, and detects an occurrence of an overload on the mobile relay station as the abnormality when an amount of change in the parameter exceeds a specified threshold value.

12. The radio communication system according to claim 10, wherein the mobile relay station further includes a reference radio wave transmission unit to transmit to the mobile station a reference radio wave which is a known radio wave used to determine a radio communication quality between the mobile relay station and the mobile station, and

wherein the detection unit measures a radio field strength of the reference radio wave transmitted from the mobile relay station, and detects an occurrence of a malfunction in the mobile relay station as the abnormality when the radio field strength falls below a specified threshold value.

13. The radio communication system according to claim 9, wherein the base station selection processing unit corrects, in accordance with the mobility state information, a parameter included in a specified evaluation formula for evaluating a communication quality of a cell, and selects the base station by using the specified evaluation formula including the corrected parameter.