Internationale Zeitschrift für Schwarmintelligenz und Evolutionsberechnung

Abstrakt

Scheduling Proximity Data Exchange for Contact Tracing

Hari TS Narayanan, Spatika Narayanan

Contact tracing is one of the popular applications of proximity data. A contact tracing system collects, stores, and computes proximity distance and duration to identify the contacts for contagious diseases like SARS and Ebola. Most of the currently deployed contact tracing solutions is built with Bluetooth Low Energy (BLE). The BLE in smartphones is used for exchanging proximity data. This exchange of proximity data could be either intrusive or non-intrusive. In intrusive exchange, the data exchange takes place after establishing a BLE connection to another smartphone. In non-intrusive exchange, periodic broadcast messages from a smartphone are scanned for proximity data. Both methods operate under technology specific and environmental constraints. Irrespective of the method, there can be collisions while accessing the media. Collision impedes data exchange and reduces the reliability of scanning. In this paper we present a heuristic for the broadcast and scanning schedules of BLE in non- intrusive exchanges. The objective of this heuristic is to optimize scanning reliability and to conserve power. The heuristic could be used for any application that requires proximity distance and duration. A reliability model is built to quantify reliability using a generalization of the Birthday Problem (BP). The schedule self regulates to changing loads under all load conditions with optimal agility. This scheduling method can be evolved for newer versions of Bluetooth.