BASE STATION, MOBILE STATION, COMMUNICATION SYSTEM, AND COMMUNICATION METHOD

• US 20110053585A1
• Filed: 08/12/2010
• Published: 03/03/2011
• Est. Priority Date: 09/01/2009
• Status: Active Grant

• Current Assignee: Fujitsu Limited
• Original Assignee: Fujitsu Limited
• Inventors: OTONARI, Junji
• Granted Patent: US 8,942,699 B2
• Time in Patent Office: Days
• US Class Current: 455/422.1
• CPC Class Codes: H04L 1/0026 Transmission of channel quality indication
• CPC Class Codes: H04L 1/0073 Special arrangements for feedback channel
• CPC Class Codes: H04W 72/27 between access points
• CPC Class Codes: H04W 72/542 using measured or perceived quality

Abstract

A base station communicates with a mobile station that receives downlink data from the base station and that transmits uplink data to a second base station. The base station includes a data transmitter configured to transmit the downlink data to the mobile station; and a control information receiver configured to receive from the mobile station through a path passing through the second base station, feedback information concerning the downlink data transmitted by the data transmitter.

Claims

1. A base station communicating with a mobile station that receives downlink data from the base station and that transmits uplink data to a second base station, the base station comprising:

a data transmitter configured to transmit the downlink data to the mobile station; and

a control information receiver configured to receive from the mobile station through a path passing through the second base station, feedback information concerning the downlink data transmitted by the data transmitter.

2. The base station according to claim 1, further comprising a forwarder configured to forward to the mobile station, feedback information transmitted from the second base station and concerning the uplink data.

3. The base station according to claim 1, further comprising a path selector configured to select, as a feedback path, any one among a path not passing through the second base station and the path passing through the second base station, wherein

the control information receiver receives the feedback information through the feedback path selected by the path selector.

4. The base station according to claim 3 further comprising:

a measuring unit configured to measure propagation quality of an uplink from the mobile station to the base station; and

a receiver configured to receive from the second base station, quality information indicative of propagation quality of an uplink from the mobile station to the second base station, wherein

the path selector, based on the propagation quality measured by the measuring unit and the quality information received by the receiver, selects the feedback path.

5. The base station according to claim 3, wherein

the path selector determines exploitability of the path passing through the second base station, and when determining that the path passing through the second base station is unexploitable, selects the path not passing through the second base station, as the feedback path.

6. The base station according to claim 5, wherein

the path selector determines that the path passing through the second base station is unexploitable, when inter-station connection with the second base station is impossible.

7. The base station according to claim 5, wherein

the path selector determines that the path passing through the second base station is unexploitable, when transmission delay in transmission of the feedback information through the path passing through the second base station exceeds a given threshold.

8. The base station according to claim 5, wherein

the path selector determines that the path passing through the second base station is unexploitable, when no allocable communication resource is available on the path passing through the second base station.

9. The base station according to claim 4, wherein

the path selector selects the feedback path according to a type of the feedback information.

10. The base station according to claim 4, wherein

the path selector selects the path not passing through the second base station, when permissible delay for the feedback information is equal to or smaller than a given threshold.

11. The base station according to claim 4, wherein

the path selector selects the path not passing through the second base station, when a feedback cycle of the feedback information is equal to or smaller than a given threshold.

12. The base station according to claim 4, wherein

the path selector selects the path not passing through the second base station, when data size of the feedback information is equal to or smaller than a given threshold.

13. The base station according to claim 4, wherein

the path selector selects the feedback path according to an encoding method for the feedback information.

14. The base station according to claim 1, communicating with a second mobile station that transmits uplink data to the base station and that receives downlink data from the second base station, the base station further comprising:

a data receiver configured to receive the uplink data from the second mobile station; and

a control information transmitter configured to transmit to the second mobile station through a path passing through the second base station, feedback information concerning the uplink data received by the data receiver.

15. A mobile station that receives downlink data from a first base station and transmits uplink data to a second base station different from the first base station, the mobile station comprising:

a data receiver configured to receive the downlink data from the first base station;

a data transmitter configured to transmit the uplink data to the second base station;

a control information transmitter configured to transmit to the first base station through a path passing through the second base station, feedback information concerning the downlink data received by the data receiver; and

a control information receiver configured to receive from the second base station through a path passing through the first base station, feedback information concerning the uplink data transmitted by the data transmitter.

16. The mobile station according to claim 15, further comprising a path information receiver configured to receive from any one of the first base station and the second base station, selection information indicative of a result of selection of a feedback path from among feedback paths including the path passing through the first base station and the path passing through the second base station, wherein

the data transmitter transmits the feedback information through the path indicated by path information received by the path information receiver, and

the data receiver receives the feedback information through the path indicated by the path information received by the path information receiver.

17. A communication method of a base station communicating with a mobile station that receives downlink data from the base station and that transmits uplink data to a second base station, the communication method comprising:

transmitting the downlink data to the mobile station; and

receiving from the mobile station through a path passing through the second base station, feedback information concerning the downlink data transmitted at the transmitting.

18. The communication method according to claim 17, wherein the base station communicates with a second mobile station that transmits uplink data to the base station and that receives downlink data from the second base station, the communication method further comprising:

receiving the uplink data from the second mobile station; and

transmitting to the second mobile station through a path passing through the second base station, feedback information concerning the uplink data received at the receiving.

19. A communication method of a mobile station that receives downlink data from a first base station and transmits uplink data to a second base station different from the first base station, the communication method comprising:

receiving the downlink data from the first base station;

transmitting the uplink data to the second base station;

transmitting to the first base station through a path passing through the second base station, feedback information concerning the downlink data received at the receiving the downlink data; and

receiving from the second base station through a path passing through the first base station, feedback information concerning the uplink data transmitted at the transmitting the uplink data.