A node clustering based approach was proposed to solve effectively the large scale WSN simulation with mul- tiple applications by partitioning nodes into different clusters. Nodes in a single cluster running the same application were simulated with the same single entity. Interactions between nodes were simulated by entity communication

and a syn- chronous mechanism was also proposed to ensure the simulation events execute orderly. A node clustering based simula- tor ETMA was designed and implemented on top of TOSSIM. Empirical studies on ETMA show that the node clustering approach can support multi-application WSN simulation with high scalability.