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.