Patent ID: 7295521

Claim:
A directional flooding method between respective sensor nodes and a sink node in a wireless sensor network in which the respective sensor nodes are constructed to know their positions, comprising the steps of: allowing the sink node to inform the respective sensor nodes of its positional information; allowing the respective sensor nodes to calculate a minimum hop count between themselves and the sink node using the positional information provided to the respective sensor nodes in combination with a transmission range of said sensor nodes, and the positional information of said sink node; allowing a sensor nodes that wants to transmits a packet to the sink node to write its corresponding minimum hop count into said packet and then to broadcast the packet; and receiving the broadcast packet at the other sensor nodes and allowing the respective sensor nodes that received the packet to compare their minimum hop counts with the minimum hop count written into the packet, and if the minimum hop count of a receiving sensor node is smaller than the minimum hop count written into the packet, allowing the respective sensor node to write its minimum hop count into the packet and then broadcast the packet, and if the minimum hop count of the receiving sensor node is not smaller than the minimum hop count written into the packet, the receiving sensor node discards the packet; said receiving step being repeated until the packet reaches the sink node.