Oasis : A Mobile Cyber-Physical System for Accessible Location Exploration

Users roaming cellular signal coverage with their mobile devices essentially form a mobile cyber-physical system (CPS). By modeling cyber human mentality and physical signal coverage, as well as their interplay, user mobility can be leveraged to improve users' mobile experience with limited wireless bandwidth. Through a real-world case study, we observed that numerous 'null zones' and 'hot zones' exist in cellular signal coverage areas, where mobile devices cannot obtain sufficiently high data rates for delay-sensitive applications. Over one third of the locations in a crowded area could have weak signal coverage and low bandwidth shares, resulting in poor mobile connectivity experience. This paper considers the practicality of a mobile CPS called Oasis, which guides users to leave those zones and move to nearby locations with better mobile experience. To realize the system, we model and maximize a user's willingness to travel to another location, where the willingness involves the compound impact of the travel distance and the improved perceptual quality. We also develop a prototype system that creates a feedback control loop to allow self-adaptation to users' needs. To evaluate the efficacy, we conducted a series of experiments based on the real data collected in downtown Taipei, Taiwan. The results demonstrate that our mobile CPS can further reduce the average distance per unit of quality improvement achieved with OpenSignalMaps by about 80%, and motivate further research.