Patent attributes
A fault-tolerant timeout protocol for distributed sensor arrays and networks in which each sensor has a plurality of backup nodes, each of which is operable to send priority information which includes the product of the time needed for the backup node to transmit sensor information to a base station and the number of tasks offered to the backup node. In another embodiment, the base station stores the two values and calculates their product. In both cases, the lowest resulting value is used by the base station to select the backup node, which then sends backup sensor information. Another aspect of the present invention is a fault-tolerant sensor integration algorithm. The algorithm creates an abstract sensor defined as an interval having values above and below the reading of an associated physical sensor, and finds a range of values common to more than half of the abstract sensors. The algorithm obtains an output value based on the common range of values, and identifies the correct sensors, possibly faulty sensors, and faulty sensors by identifying the abstract sensors that include, respectively, (a) all of the common range, (b) part of the common range, and (c) none of the common range. A further aspect of the invention is a multi-hop information forwarding method for a wireless network. According to this method, a data source node transmits a signal to neighboring nodes among a plurality of distributed nodes, and each neighboring node which receives the signal from the source node transmits a reply signal which includes a weighted sum of factors including an energy factor and a distance factor for the neighboring node, the energy factor being indicative of the neighboring node's energy level and the distance factor being indicative of its distance from the source node. A forwarding node is selected on the basis of the weighted sums, and the source node transmits a data packet to the selected forwarding node, where the data packet is received and retransmitted either to a data sink node, e.g., a base station, or to another forwarding node.
