Energy-efficient network protocol and node device for sensor networks
First Claim
1. A method for forming a wireless network comprised of a plurality of nodes including a main node, wherein the plurality of nodes transmit and receive information between each other and ultimately to the main node in a tree-like configuration, the method comprising:
- periodically transmitting a local node information message from a first node, the local node information message comprising synchronization information pertaining to a clock of the first node and network tree information with respect to the first node, wherein the network tree information comprises an identifier of the first node, an address of the main node, number of node hops from the first node to the main node, information indicating remaining battery life of the first node, number of downstream nodes with respect to the first node, and maximum number of node hops from any node in the network to the main node;
at the first node, computing the period at which the first node periodically transmits the local node information message as A1*LneHopInterval+A2*BatteryLifeInterval+A3*LneCountInterval+A4*NumMbrInterval+random(LneXmtInterval), where A1 is a factor derived from the number of node hops from the first node to the main node divided by the maximum number of node hops from any node in the network to the main node, A2 is a factor derived from a remaining battery level of the first node divided by a maximum battery level possible at the first node, A3 is a factor representing a local node information message count staffed from 0 and incremented by one each time the first node transmits a local node information message and A4 is a factor representing the number of downstream nodes with respect to the first node, and where LneHopInterval, BatteryLifeInterval, LneCountInterval and NumMbrInterval are time interval values that are weighted by the factors A1, A2, A3 and A4, respectively, and random(LneXmtInterval) is a random function of a time transmit time interval quantity;
receiving at a second node that is not currently joined to the network the local node;
information message transmitted by the first node that is joined to the network;
said second node synchronizing to the clock of the first node based on the synchronization information contained in the local node information message and thereby becoming time-synchronized to the network; and
said second node determining whether to join the network at the first node based on the network tree information contained in the local node information message received from the first node.
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Abstract
An “on-demand” approach for a routing protocol for a wireless network that achieves balanced energy consumption among all participating nodes in the network. Synchronization messages transmitted by nodes associated with an upstream node include local node information (LNI) that a node can use to repair or bypass a lost upstream node in a real or virtual (temporary) manner depending upon the local node'"'"'s battery level. Only if a repair process fails will a global re-organization (Re-Org) be initiated. The LNI also allows for nodes having lower power availability (battery level) not to transmit the LNI so that unaffiliated node(s) can select an upstream node having more power availability thereby extending network life.
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Citations
21 Claims
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1. A method for forming a wireless network comprised of a plurality of nodes including a main node, wherein the plurality of nodes transmit and receive information between each other and ultimately to the main node in a tree-like configuration, the method comprising:
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periodically transmitting a local node information message from a first node, the local node information message comprising synchronization information pertaining to a clock of the first node and network tree information with respect to the first node, wherein the network tree information comprises an identifier of the first node, an address of the main node, number of node hops from the first node to the main node, information indicating remaining battery life of the first node, number of downstream nodes with respect to the first node, and maximum number of node hops from any node in the network to the main node; at the first node, computing the period at which the first node periodically transmits the local node information message as A1*LneHopInterval+A2*BatteryLifeInterval+A3*LneCountInterval+A4*NumMbrInterval+random(LneXmtInterval), where A1 is a factor derived from the number of node hops from the first node to the main node divided by the maximum number of node hops from any node in the network to the main node, A2 is a factor derived from a remaining battery level of the first node divided by a maximum battery level possible at the first node, A3 is a factor representing a local node information message count staffed from 0 and incremented by one each time the first node transmits a local node information message and A4 is a factor representing the number of downstream nodes with respect to the first node, and where LneHopInterval, BatteryLifeInterval, LneCountInterval and NumMbrInterval are time interval values that are weighted by the factors A1, A2, A3 and A4, respectively, and random(LneXmtInterval) is a random function of a time transmit time interval quantity; receiving at a second node that is not currently joined to the network the local node;
information message transmitted by the first node that is joined to the network;said second node synchronizing to the clock of the first node based on the synchronization information contained in the local node information message and thereby becoming time-synchronized to the network; and said second node determining whether to join the network at the first node based on the network tree information contained in the local node information message received from the first node. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16)
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17. A wireless network node device, comprising:
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a receiver configured to receive signals from other nodes in a network; a transmitter configured to transmit signals to other nodes in the network; a processor coupled to the receiver and to the transmitter, wherein the processor is configured to; generate a local node information message to be transmitted to other nodes, wherein the local node information message comprises synchronization information pertaining to a clock and network tree information, wherein the network tree information comprises a node identifier, an address of a main node, number of node hops to the main node, information indicating remaining battery life, number of downstream nodes, and maximum number of node hops from any node in the network to the main node; compute a period at which the local node information message is to be periodically transmitted based on a formula A1*LneHopInterval+A2-BatteryLifeInterval+A3*LneCountInterval+A4*NumMbrInterval+random(LneXmtInterval), where A1 is a factor derived from the number of node hops to the main node divided by the maximum number of node hops from any node in the network to the main node, A2 is a factor derived from a remaining battery level divided by a maximum battery level possible, A3 is a factor representing a local node information message count started from and incremented by one each time the local node information message is transmitted and A4 is a factor representing the number of downstream nodes, and where LneHopInterval, BatteryLifeInterval, LneCountInterval and NumMbrInterval are time interval values that are weighted by the factors A1, A2, A3 and A4, respectively, and random(LneXmtInterval) is a random function of a time transmit time interval quantity; and supply the local node information message to the transmitter for transmission. - View Dependent Claims (18, 19, 20, 21)
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Specification