WSAN simultaneous failures recovery method

摘要

The WSAN simultaneous failures recovery method ranks each node based on the number of hops to a pre-designated root node in the network. The method identifies some nodes as cluster heads based on the number of their children in the recovery tree. The method assigns a recovery weight and a nearby cluster node to each node. Nearby cluster nodes serve as gateways to other nodes that belong to that cluster. The recovery weight is used to decide which node is better to move in order to achieve lower recovery cost. The recovery method uses the same on-going set of actors to restore connectivity. Simulation results have demonstrated that the recovery method can achieve low recovery cost per failed node in small and large networks. The results have also shown that clustering leads to lower recovery cost if the sub-network needs to re-establish links with the rest of the network.

主权项

1. In a wireless sensor-actor network (WSAN) having a topology defined by a plurality of connected sensor nodes and actor nodes, a computer- implemented WSAN simultaneous failures recovery method, comprising the steps of:
searching the plurality of connected sensor nodes and actor nodes in a breadth first search (BFS) manner, starting at a root node; assigning a rank to the plurality of connected sensor nodes and actor nodes during the BFS of the plurality of connected sensor nodes and actor nodes, wherein the rank of each of the plurality of connected sensor nodes and actor nodes is determined by a number of shortest hops to the root node of the wireless sensor-actor network; creating a recovery tree based on the rank assigned to the plurality of connected sensor nodes and actor nodes, the recovery tree having parent nodes; defining roles of the plurality of connected sensor nodes and actor nodes based on levels of the plurality of connected sensor nodes and actor nodes in the recovery tree; assigning a clustering weight and a recovery weight to each of the plurality of connected sensor nodes and actor nodes, the recovery weight being based on a number of hops to a particular one of the plurality of connected sensor nodes and actor node's closest leaf node in the recovery tree, the recovery weight being used to determine how the plurality of connected sensor nodes and actor nodes are to move to restore connectivity, the clustering weight being based on the number of children nodes down in the recovery tree until a cluster is encountered, the clustering weight being used to determine which of the plurality of connected sensor nodes and actor nodes will form a new cluster head; each of the plurality of connected sensor nodes and actor nodes checking its clustering weight against a predefined cluster size and when its clustering weight exceeds the predefined cluster size establishing itself as a cluster head and sending cluster identification to the cluster head's neighbor nodes; monitoring the network for the occurrence of a node failure; upon determination of a failed node, each of the plurality of connected sensor nodes and actor nodes in a set of children nodes of the failed node in the recovery tree recursively transmitting its assigned recovery weight and an ID of its parent to other ones of the plurality of connected sensor nodes and actor nodes in the set of children nodes of the failed node and saving received assigned recovery weights and IDs from the other ones of the plurality of connected sensor nodes and actor nodes in the set of children nodes of the failed node, each of the plurality of connected sensor nodes and actor nodes in the set of children nodes of the failed node ceasing transmission of its assigned recovery weight and saving of received assigned recovery weights when a received assigned recovery weight is lower than its own assigned recovery weight, thereby leaving the other children nodes of the failed node with lower weight to recover; moving each of the plurality of connected sensor nodes and actor nodes to positions having ranks that are at most half of the rank of the failed nodes away from the failed node, one of the plurality of connected sensor nodes and actor nodes becoming a recovering node taking the place of the failed node in the recovery tree.