Area-limited self-organized network management method, communications apparatus, and system

A communications apparatus comprising:

• a receiver to receive area limiting signals for limiting an area;
• a surrounding node detector configured to, when the communications apparatus which is entering the limited area receives the area limiting signals, detect whether there is a master node in the limited area;
• and
• a role switch configured to, if it is determined that there is the master node in the limited areas, let the communications apparatus perform identity authentication with regard to the master node based on the area limiting signals so as to become a sub node, and if it is determined that there is not the master node in the limited area, let the communications apparatus be the master node, wherein, the master node is in charge of entering of a new sub node and synchronization of shared secret keys between network nodes of a network,
• wherein when there are plural master nodes in the network, any one of the plural master nodes sends its priority indicating a priority level of being a master node to other master nodes, and if a master node finds that there is another master node whose priority is higher than that of the master node, then the master node automatically becomes a sub node.

An area-limited wireless communications system comprising:

• area limiting signal transmitting apparatuses configured to transmit area limiting signals for limiting an area;
• and
• plural wireless communications apparatuses dynamically located in the limited area,
• wherein:
• one of the plural wireless communications apparatuses serves as a master node, and the others serve as sub nodes, wherein, the master node is in charge of entering of a new sub node and synchronization of shared secret keys between network nodes of a network, and when the master node disappears, one of the sub nodes automatically becomes a new master node,
• in a case where there is only one wireless communications apparatus in the area-limited wireless communications system, the wireless communications apparatus becomes the master node;
• after that, when a new wireless communications apparatus enters, the new wireless communications apparatus becomes a sub node,
• each sub node has a priority assigned by the master node, and the priority indicates a priority level of a corresponding one of the sub nodes becoming a new master node;
• one of the communications apparatuses serving as a sub node periodically detects a state of the master node, wherein, if said one of the sub nodes does not detect the master node in a predetermined time period, and the priority of said one of the sub nodes is higher than those of other sub nodes, then said one of the sub nodes automatically becomes a new master node, and informs the other sub nodes that the master node has changed,
• the master node periodically detects states of the respective sub nodes, wherein, if the master node does not detect a sub node in a predetermined time period, then the master node regards the non-detected sub node as having disappeared, changes a shared secret key, and informs other sub nodes of the changed shared secret keys and information indicating that the non-detected sub node has disappeared, and
• when there are plural master nodes in the network, any one of the plural master nodes sends its priority indicating a priority level of being a master node to other master nodes, and if a master node finds that there is another master node whose priority is higher than that of the master node, then the master node automatically becomes a sub node.