Content-based multipath routing for sensor networks

In wireless sensor networks, in-network processing of aggregation queries has been an important technique to reduce energy consumption in wireless communication, which is a main source of energy consumption in sensor devices. In-network processing is typically guided by an aggregation tree, where each node forwards partially computed aggregates to its parent. In this paper we consider a routing method for grouped aggregation queries, where sensor readings are divided into disjoint groups according to their values and aggregates are computed for each group. For this type of queries, multipath routing, where each node forwards different aggregates to different nodes, can lead to more efficient in-network processing. However, no multipath routing protocol for efficient in-network processing of grouped aggregation queries has been proposed thus far. In this paper we propose a new routing protocol, called Content-based Multipath Routing (CMR), for efficient in-network processing of grouped aggregation queries. CMR employs multipath routing, and each node forwards partially computed aggregates along different paths based on the contents of the aggregates. The experimental results show that CMR outperforms the existing aggregation tree-based routing protocols.