Density maps: Determining where to sample in participatory sensing systems

Participatory sensing (PS) systems are a new emerging sensing paradigm based on the participation of cellular users. While they present interesting characteristics, such as spatiotemporal granularity and low cost, they also create new problems and challenges. One key challenge in PS systems is that of the determination of the locations and number of users where to obtain samples from so that we can accurately represent the variable of interest with a low number of participants. This paper proposes the use of density maps, based on the current estimations of the variable, to address this challenge. The density maps are then utilized by the incentive mechanism in order to encourage the participation of those users indicated in the map. Our results show how the density maps greatly improve the quality of the estimations while maintaining a stable and low total number of users in the system.