This work focuses on practical research in the field of Bluetooth 5.0 and the maximum number of Bluetooth sensors nodes in a wireless body area network (WBAN) for human activity recognition (HAR). As network topology M:1 multi-pairing is used. For the best of our knowledge no direct related work in this field can be found. We investigated how many Bluetooth connections can be simultaneously connected with different smartphones (iOS) with real sensor data and in which time intervals the data can still be processed and stored. Our results show that a maximum of 14 Bluetooth devices can be connected under practical conditions. A stable transmission with 48~bytes per package are found with most reliability in an minimal interval of 40~ms per node.

Bluetooth; Internet of Things; performance-evaluation; wireless body area network (WBAN); sensor networks; NINA