Terminal capable of substituting for control station

Abstract

A terminal of the present invention comprises a control frame detection portion of detecting a control frame issued from a control station, a control frame memory portion of storing control information contained in the control frame, a substitute frame issuance determination portion of determining to issue a substitute frame when the control frame is not detected until a predetermined first time period is elapsed, and a substitute frame issuance portion of creating a frame which is the same as or equivalent to the control frame, as the substitute frame, based on the control information stored in the control frame memory portion when the substitute frame issuance determination portion determine to issue the substitute frame, and issuing the created substitute frame.

Description

TECHNICAL FIELD [0001] The present invention relates to a terminal whose opportunity to access a communication medium is controlled by a control station, and more particularly, to a terminal capable of substituting for a control station. BACKGROUND ART [0002] A communication system which utilizes media having a problem with communication quality is provided with a control station for controlling media access of other station(s) in order to utilize media as efficiently as possible. The other station is regarded as a controlled station, i.e., the control station and the controlled station have a master-slave relationship. In this manner, a central control type communication system protocol which can improve the efficiency of the entire communication system has been developed. [0003] When such a protocol is applied to a wireless LAN, a power line communication system and the like, the efficiency of media access in the communication system is significantly influenced by communication qu...

AI Technical Summary

Benefits of technology

[0010] Therefore, a first object of the present invention is to provide a terminal having a guaranteeing mechanism such that, when an operating control station is disconnected from a communication system for some reason, media access of the communication system can be prevented from falling into an inefficient situation for a long time, without sudden replacement with a new control station. Further, a second object of the present invention is to provide a terminal having a mechanism such that, when a control station which has been disconnected from a communication system is recovered, a media access control is returned to the original control station. Furthermore, a third object of the present invention is to a terminal which can maintain the communication quality of a whole communication system using a simple mechanism against temporary disconnection of a control station.

[0031] Hereinafter, effects of the present invention will be described. According to the present invention, when a control station which plays an important role in maintaining communication quality is disconnected from a communication system for some reason, a substitute frame which is the same as or equivalent to a control frame previously transmitted, is transmitted. Therefore, communication quality which is the same as that at the time of the disconnection is maintained, and in addition, it is possible to avoid a situation that media access to the communication system falls into an inefficient state for a long time.

[0033] Also, when the original control station does not resume communication after the predetermined time period is elapsed, a new control station starts operating, thereby making it possible to avoid a situation that a control station is absent for a long time period.

[0035] Thus, a terminal having a simple mechanism and capable of maintaining communication quality of an entire communication system is provided, thereby making it possible to minimize a decrease in communication quality in a communication system.

Problems solved by technology

However, in the technology of Patent Publication 1, it is not possible to reconstruct a control station, so that the communication quality of a communication system cannot be maintained.

Therefore, unless a control station is determined, taking into consideration the location on a network of connection of a terminal, the performance of a terminal, or the like, there is a possibility that the communication quality is significantly impaired upon replacement.

In this case, it may be difficult to reconstruct a control station using latest information, a control request which has been once accepted may be lost so that latest information cannot be inherited, or a network system itself may not function.

Therefore, when a control station is disconnected from a communication system, in general it is not always satisfactory to replace the control station with a new one.

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