Convergecast is a fundamental operation in wireless sensor networks. Existing convergecast solutions have focused on reducing latency and energy consumption. However, a good design should be compliant to standards, in addition to considering these factors. Based on this observation, this paper defines a minimum delay beacon scheduling problem for quick convergecast in ZigBee/IEEE 802.15.4 tree-based wireless sensor networks and proves that this problem is NP-complete. Our formulation is also compliant with the low-power design of IEEE 802.15.4. We then propose optimal solutions for special cases and heuristic algorithms for general cases. Simulation results show that the proposed algorithms can indeed achieve quick convergecast. Categories and Subject Descriptors C.2.1 [[Computer-Communication Networks]: Network Architecture and Design—Distributed networks, Wireless communication; G.2.2 [Discrete Mathematics]: Graph Theory General Terms Algorithms, Design, Theory. Keywords converge...