Terminal device and method for use in media access communication system

• US 20050033816A1
• Filed: 08/05/2004
• Published: 02/10/2005
• Est. Priority Date: 08/06/2003
• Status: Active Grant

• Current Assignee: Panasonic Corporation (Panasonic Holdings Corporation)
• Original Assignee: Panasonic Corporation (Panasonic Holdings Corporation)
• Inventors: Ohmi, Shinichiro, Yamaguchi, Tsuyoshi, Yoshizawa, Kensuke
• Granted Patent: US 7,447,746 B2
• Time in Patent Office: Days
• US Class Current: 709/208
• CPC Class Codes: H04W 84/20 Master-slave selection or change arrangements

Abstract

Terminal devices F and G store statistical information related to interference from an external communication system, and notify the stored statistical information to a master station E. The master station E determines the terminal device G as a candidate station for a master station capability handover destination based on collected statistical information. The master station E requests to hand over a master station capability to the terminal device G. If it is determined that the terminal device G accepts handover of the master station capability, the terminal device G starts to act as the master station.

Claims

1. A terminal device for use in a communication system in which a master station controls access of slave stations to a communication medium, the communication system being provided adjacent to an external communication system, the terminal device comprising:

master and slave stations management means for managing whether the terminal device should act as the master station or as a slave station;

communication status information storage means for, if the terminal device is managed by the master and slave stations management means so as to act as the slave station, storing, as communication status information, information related to a communication status in the external communication system;

communication status information notification means for, if the terminal device is managed by the master and slave stations management means so as to act as the slave station, notifying the communication status information stored in the communication status information storage means to the master station in the communication system;

communication status information collection means for, if the terminal device is managed by the master and slave stations management means so as to act as the master station, collecting the communication status information from the slave stations in the communication system;

master station capability handover destination station determination means for, if the terminal device is managed by the master and slave stations management means so as to act as the master station, referring to the communication status information collected by the communication status information collection means and determining, from among slave stations in the communication system having notified the communication status information, a slave station, which satisfies a predetermined handover requirement, as a candidate for a master station capability handover destination station to which a master station capability is entirely or partially handed over; and

master station capability handover request means for, if the terminal device is managed by the master and slave stations management means so as to act as the master station, requesting a handover of the master station capability to the candidate for the master station capability handover destination station determined by the master station capability handover destination station determination means,

wherein in a state where the terminal device is managed so as to act as the slave station, if the master station in the communication system requests the handover of the master station capability, the master and slave stations management means determines whether the terminal device satisfies a master station predetermined requirement, and if the predetermined master station requirement is satisfied, the master and slave stations management means changes a management detail such that the terminal device acts as the master station.

2. The terminal device according to claim 1, wherein the communication status information is interference information related to a signal received from the external communication system.

3. The terminal device according to claim 1, further comprising master station capability handover start notification means for, if the master and slave stations management means determines that the terminal device should act as the master station, and starts a change of the management detail, notifying the external communication system that handover of the master station capability has started.

4. The terminal device according to claim 1, wherein the master station capability handover start notification means notifies the handover of the master station capability by describing in a specific region of a broadcast beacon frame that handover of the master station capability has started.

5. The terminal device according to claim 3, wherein the master station capability handover start notification means notifies the external communication system that handover of the master station capability has started, to prohibit a handover process of the master station capability from being performed in the external communication system.

6. The terminal device according to claim 3, further comprising master station capability handover completion notification means for, if the master and slave stations management means determines that the terminal device should act as the master station, and completes the change of the management detail, notifying the external communication system that the handover of the master station capability has been completed.

7. The terminal device according to claim 6, wherein the master station capability handover completion notification means notifies completion of the handover of the master station capability by describing in a specific region of a broadcast beacon frame that the handover of the master station capability has been completed.

8. The terminal device according to claim 6,

wherein the master station capability handover start notification means notifies the external communication system that handover of the master station capability has started, to prohibit a handover process of the master station capability from being performed in the external communication system, and

wherein the master station capability handover start notification means notifies the external communication system that the handover of the master station capability has been completed, to cancel prohibition of the handover process of the master station capability in the external communication system.

9. The terminal device according to claim 2, wherein the interference information is information related to a number of signals received from the external communication system.

10. The terminal device according to claim 2, wherein the interference information is information related to a number of source terminal devices of signals received from the external communication system.

11. The terminal device according to claim 1,

wherein if a terminal device in the external communication system detects a frame transmitted from the terminal device in the communication system, the terminal device in the external communication system notifies information related to a reception signal intensity of the frame to the terminal device in the communication system having transmitted the frame, and

wherein the communication status information is information related to the reception signal intensity notified by the external communication system.

12. The terminal device according to claim 1, wherein the master station capability handover destination station determination means determines the master station capability handover destination station based on a number of retransmissions of a frame transmitted from the slave station.

13. The terminal device according to claim 1, wherein the master station capability handover destination station determination means determines the master station capability hand over destination station based on a signal amplification factor of a signal received by the slave station.

14. The terminal device according to claim 1, wherein the master station capability handover destination station determination means determines the master station capability handover destination station based on a type of a frame received by the slave station.

15. The terminal device according to claim 1, wherein the master station capability handover destination station determination means determines the master station capability handover destination station based on a number of frames received by the slave station.

16. The terminal device according to claim 1, wherein the master station capability handover request means requests the handover of the master station capability by transmitting a request frame for requesting the handover of the master station capability to the candidate for the master station capability handover destination station.

17. The terminal device according to claim 16, further comprising response frame transmission means for, if the master and slave stations management means determines that the predetermined master station requirement is satisfied, transmitting a response frame, which indicates that the handover of the master station capability has been accepted, to the master station.

18. The terminal device according to claim 17, wherein the response frame transmission means transmits the response frame which describes information related to time to hand over the master station capability.

19. A terminal device for use in a communication system in which a master station controls access of slave stations to a communication medium, the communication system being provided adjacent to an external communication system, each of the slave station having stored therein information related to a communication status in the external communication system as communication status information, the terminal device comprising:

communication status information collection means for collecting the communication status information from the slave stations in the communication system;

master station capability implementation station determination means for referring to the communication status information collected by the communication status information collection means and selecting, from among slave stations in the communication system having notified the communication status information, a slave station, which satisfies a predetermined handover requirement, as a candidate station for entirely or partially implementing a master station capability; and

master station capability implementation request means for requesting the candidate station determined by the master station capability implementation station determination means to implement the master station capability.

20. A method for entirely or partially handing over a master station capability to a slave station in a communication system in which a master station controls access of slave stations to a communication medium, the communication system being provided adjacent to an external communication system, each terminal device on the communication system being operable to act as the master or slave station, the method comprising the steps of:

causing a terminal device acting as the slave station to store, as communication status information, information related to a communication status in the external communication system;

causing the terminal device acting as the slave station to notify the communication status information stored therein to the master station in the communication system;

causing a terminal device acting as the master station to collect the communication status information from the slave stations in the communication system;

causing the terminal device acting as the master station to refer to the communication status information collected by the communication status information collection means and to determine, from among slave stations in the communication system having notified the communication status information, a slave station, which satisfies a predetermined handover requirement, as a candidate for a master station capability handover destination station to which a master station capability is entirely or partially handed over;

causing the terminal device acting as the master station to request a handover of the master station capability from the candidate;

determining whether the candidate satisfies a predetermined master station requirement; and

if the predetermined master station requirement is satisfied, causing the candidate to act as the master station.