Base station apparatus, mobile station apparatus, and method of assigning subscarriers

• US 20090016291A1
• Filed: 09/11/2008
• Published: 01/15/2009
• Est. Priority Date: 03/17/2006
• Status: Active Grant

• Current Assignee: Fujitsu Limited
• Original Assignee: Fujitsu Limited
• Inventors: Oota, Yoshiyuki, Iwamatsu, Takanori
• Granted Patent: US 8,249,001 B2
• Time in Patent Office: Days
• US Class Current: 370/329
• CPC Class Codes: H04L 5/0023 Time-frequency-space
• CPC Class Codes: H04L 5/0037 Inter-user or inter-terminal allocation
• CPC Class Codes: H04L 5/0091 Signaling for the administration of the divided path

Abstract

A base station assigns a subcarrier for downlink communications under Orthogonal Frequency Division Multiple Access. Before downlink communications with a mobile station, based on carrier sensing by the mobile station, the base station detects information concerning an available subcarrier from downlink signals using a modulating unit. The information concerning the available subcarrier is stored in a downlink-information sharing unit and is shared among the base station and the adjacent base stations. A downlink subcarrier setting unit sets the available subcarrier for downlink communications.

Claims

1. A base station apparatus assigning a subcarrier in downlink communication under Orthogonal Frequency Division Multiple Access and comprising:

an obtaining unit that obtains, before downlink communication with a mobile station apparatus, information resulting from carrier sensing by the mobile station apparatus and concerning an available subcarrier;

an information sharing unit that informs an adjacent base station apparatus of the information concerning the available subcarrier, the information concerning the available subcarrier being shared between the base station apparatus and the adjacent base station apparatus; and

a subcarrier setting unit that sets the available subcarrier for the downlink communication before the downlink communication with the mobile station apparatus.

2. The base station apparatus according to claim 1, wherein the information sharing unit informs a base station apparatus in one or more adjacent cells of the information concerning the available subcarrier, the information concerning the available subcarrier being shared among the base station apparatus and a base station apparatus in one or more adjacent cells.

3. The base station apparatus according to claim 1, wherein the subcarrier setting unit sets the available subcarrier for the downlink communication based on any one of or any combination of data volume, number of users of the mobile station apparatus, quality of service, and propagation environment.

4. The base station apparatus according to claim 1, wherein the obtaining unit extracts the information concerning the available subcarrier from a signal of uplink communication with the mobile station apparatus.

5. The base station apparatus according to claim 1, further comprising:

a setting unit that sets a threshold used for detection of the available subcarrier by the mobile station apparatus through carrier sensing; and

an inserting unit that inserts information concerning the threshold into the signal of the downlink communication in order to set the information concerning the threshold to the mobile station apparatus.

6. A base station apparatus assigning a subcarrier in uplink communication under Orthogonal Frequency Division Multiple Access and comprising:

a detecting unit that performs carrier sensing before uplink communication with a mobile station apparatus and detects an available subcarrier;

an information sharing unit that informs an adjacent base station apparatus of information concerning the available subcarrier, the information concerning the available subcarrier being shared between the base station apparatus and the adjacent base station apparatus; and

a subcarrier setting unit that sets the available subcarrier for the uplink communication before the uplink communication with the mobile station apparatus.

7. The base station apparatus according to claim 6, wherein the information sharing unit informs a base station apparatus in one or more adjacent cells of the information concerning the available subcarrier, the information concerning the available subcarrier being shared among the base station apparatus and a base station apparatus in one or more adjacent cells.

8. The base station apparatus according to claim 6, wherein the detecting unit performs the carrier sensing for one or more adjacent cells.

9. The base station apparatus according to claim 6, wherein the subcarrier setting unit sets the available subcarrier for the uplink communication based on any one of or any combination of an uplink bandwidth request, number of users of the mobile station apparatus, quality of service, and propagation environment.

10. A mobile station apparatus communicating with a base station apparatus that assigns a subcarrier in uplink communication under Orthogonal Frequency Division Multiple Access, the mobile station apparatus comprising:

a detecting unit that performs carrier sensing before downlink communication with the base station apparatus and detects an available subcarrier; and

an informing unit that inserts information concerning the available subcarrier into an uplink signal to the base station apparatus to inform the base station apparatus of the information.

11. The mobile station apparatus according to claim 10, further comprising:

an extracting unit that extracts information inserted into a downlink signal from the base station apparatus and concerning a threshold,

wherein the detecting unit detects the available subcarrier based on the information concerning the threshold.

12. A method of assigning a subcarrier under Orthogonal Frequency Division Multiple Access and comprising:

detecting an available subcarrier through carrier sensing by a signal-receiving apparatus that is a base station apparatus or a mobile station apparatus, before communication between the base station apparatus and the mobile station apparatus;

sharing information concerning the available subcarrier among the base station apparatus and an adjacent base station apparatus; and

assigning the subcarrier to communication between the base station apparatus and the mobile station apparatus before the communication begins.

13. The method according to claim 12, wherein the available subcarrier is assigned based on any one of or any combination of data volume, number of users of the mobile station apparatus, quality of service, and propagation environment.