Network system, radio communication device, radio communication method, and computer program for the same
First Claim
1. A network system for forming a network topology with a plurality of nodes each having a radio communication function and a traveling function and operating in a self-directive and dispersive state, wherein each node has first and second states in which the node travels with said traveling function and searches for information for connectivity with neighboring nodes and a third state in which travel with said traveling function is stopped, and a node in the first state shifts to said third state when a first condition is satisfied and a node in the second state shifts to the third state when a second condition different from said first condition is satisfied, and each node finally shifts to said third state dynamically switching between said first state and said second state to form a network topology.
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Abstract
A network system, radio communication device, radio communication method, and computer program for same are provided. The present invention enables formation of a network topology with sensor nodes each having a traveling function and operating in the self-directive and dispersive state without using positional information. Each sensor nodes periodically transmits a HELLO message to neighboring nodes to exchange information therewith. In an area where the node density is high, the nodes are set in the Expand state and in the Bridge state. A node in the Expand state shifts to the Stay state when the node can be connected to only one neighboring node to becomes a component of the topology. A node in the Bridge state shifts to the Stay state together with neighboring nodes each having hidden terminals not less than a prespecified number to become a component of the topology.
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Citations
26 Claims
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1. A network system for forming a network topology with a plurality of nodes each having a radio communication function and a traveling function and operating in a self-directive and dispersive state,
wherein each node has first and second states in which the node travels with said traveling function and searches for information for connectivity with neighboring nodes and a third state in which travel with said traveling function is stopped, and a node in the first state shifts to said third state when a first condition is satisfied and a node in the second state shifts to the third state when a second condition different from said first condition is satisfied, and each node finally shifts to said third state dynamically switching between said first state and said second state to form a network topology.
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13. A radio communication device operating as a sensor node in a sensor network and comprising:
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a sensor for acquiring desired information at a current position;
a radio communication function unit for executing communication with neighboring sensor nodes;
a traveling function unit for moving a position of said device; and
a control unit for processing information acquired by said sensor and controlling operations of each of said function units, wherein said control unit dynamically switches an operating state of said sensor node, based on information on connectivity to neighboring nodes acquired by said radio communication function unit, between first and second states in each of which said radio communication device travels and searches for information on connectivity to neighboring nodes, shifts the operating state of said sensor node to a third state in which traveling with said traveling function unit is stopped when a first condition is satisfied in said first state, and further shifts to said third state when a second condition different from said first condition is satisfied in said second state. - View Dependent Claims (14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24)
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25. A radio communication method enabling a radio communication device having a sensor, a radio communication function and a traveling function to operate as a sensor node in a sensor network, said method comprising the steps of:
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dynamically switching, based on information on connectivity to neighboring nodes acquired by said radio communication function, between the first and second states in each of which each node travels with said traveling function and searches for information on connectivity with neighboring node;
shifting from the first state to the third state in which traveling with said traveling function is stopped when a first condition is satisfied; and
shifting from the second state to the third state in which when the second state different from the first condition is satisfied.
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26. A computer program described with a computer-readable format and enabling a radio communication device having a sensor, a radio communication function and a traveling function to operate as a sensor node in a sensor network, said computer program enabling execution of the radio communication method comprising the steps of:
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dynamically switching, based on information on connectivity to neighboring nodes acquired by said radio communication function, between the first and second states in each of which each node travels with said traveling function and searches for information on connectivity with neighboring node;
shifting from the first state to the third state in which traveling with said traveling function is stopped when a first condition is satisfied; and
shifting from the second state to the third state in which when the second state different from the first condition is satisfied.
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Specification