This work presents a distributed time slot assignment algorithm which adopts TDMA as Medium Access Control, specially suited to support applications with strict delay, jitter and throughput requirements characterized by convergecast traffic patterns in sensor networks. (E.g. wireless video surveillance sensor networks). Our algorithm has three characteristics: (1) Every node is guaranteed a path to the base station for its data delivery. In the path, sufficient resource is reserved and weighted fairness can be achieved. (2) It uses cascading time slot assignment and jitter minimization algorithm in each node to minimize jitter and end to end delay (3) Nodes are only active during their scheduled slots and sleep otherwise. This offers energy saving by reducing idle listening and avoiding overhearing. The performance of the proposed algorithm is evaluated over simulations and analyzed theoretically in comparison with FlexiTP which is a recently proposed delay aware MAC protocol. The results show that our algorithm provides lower end-to-end delay, jitter and higher throughput.