Constructing Maximum-Lifetime Data Gathering Trees in Sensor Networks with Data Aggregation

This paper studies the problem of constructing maximum-lifetime data gathering trees in sensor networks in which the power levels of sensors are heterogeneous and adjustable. In-network data aggregation is also employed to aggregate sensor data while they are being forwarded toward the base station. For sensor networks in which sensors have fixed and the same transmission power level, Wu et al. has derived an upper bound on the lifetime of the optimal data gathering tree and developed an approximation algorithm for constructing data gathering trees. The model considered in this paper is more general than that considered by Wu et al. in that the transmission power levels of sensors are heterogeneous and adjustable. For this more general model, this paper derives an upper bound on the lifetime of the optimal data gathering tree. Given an initial tree, an algorithm is developed to construct a data gathering tree by iteratively rearranging the current tree and improving the lifetime of the current tree. The worst-case computational complexity of the algorithm is shown to be polynomial.