In this paper we present a protocol for sensor applicationsthat require periodic collection of raw data reportsfrom the entire network in a timely manner. We formulatethe problem as an NP-hard graph coloring problem. Wethen present TIGRA - a distributed heuristic for graph coloring that takes into account application semantics and special characteristics of sensor networks. TIGRA ensures that no interference occurs and spatial channel reuse is maximized by assigning a specific time slot for each node totransmit. Although the end-to-end delay incurred by sensordata collection largely depends on specific topology,platform, and application, TIGRA provides a transmissionschedule that guarantees near-optimal delay on sensor datacollection.