Abstract
In sensor network applications where data collection is acceptable or sufficient, hop-by-hop acknowledgement is not required for data delivery. The power level of each node on a data gathering tree can be adjusted to be just high enough to reach its parent node. 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. This paper derives an upper bound on the lifetime of the optimal data gathering tree. For a given initial tree, an algorithm is developed to construct a data gathering tree by iteratively rearranging the current tree and improving the lifetime. Simulations are performed to study the performance of the algorithm.