Bluetooth Performance Evaluation based on Notify for Real-time Body-Area Sensor Networks

This work focuses on the analysis of Bluetooth Sensor Networks and the maximum number of Bluetooth sensors nodes for real-time human activity recognition (HAR). M:1 multi-pairing is used as network topology. The tests use notify for the Bluetooth data transmission. We investigated the quality of service (QoS) for the maximum number of Bluetooth connections with real-time sensor data based on inertial measurement units (IMU). We show how many Bluetooth sensor nodes can be simultaneously connected using different commercial off-the-shelf hardware and OS. On top of that we point out how the package loss behaves depending on the set time interval and used hardware. Our results show that a maximum number of 13 Bluetooth sensor nodes can be connected using an external Bluetooth dongle with the Linux OS. Connecting more than 10 Bluetooth sensor nodes at a frequency of 0.025 s tested in the Thinkpad P53 in combination with the DeLock Bluetooth dongle being most useful. This combination allowed a maximum number of simultaneous connections by having only a package loss of about 1.2%.