Simulation scalability issues in wireless sensor networks

The formidable growth of WSN research has opened challenging issues about their performance evaluation. Despite the steady increase in mathematical analysis and experimental deployments, most of the community has chosen simulation for their study. Although it seems straightforward, this approach becomes quite a delicate matter. Complexity is caused by several issues. First, the large number of nodes heavily impacts simulation performance and scalability. Second, credible results demand an accurate characterization of the sensor radio channel. New aspects inherent in WSN must be included in simulators (e.g., a physical environment and an energy model), leading to different degrees of accuracy vs. performance. Moreover, many necessary models are in the continuous time domain (e.g., heat transmission, battery discharge), and thus complex to integrate into discrete event network simulators. These issues result in exponential growth of overall network state information. Through this survey we review these problems both quantitatively and qualitatively while depicting a common suitable simulation model. We also briefly describe the most significant simulation frameworks available.