BLE Extended Advertisements for Energy Efficient and Reliable Transfer of Large Sensor Data in Monitoring Applications

Advertising extensions introduced in Bluetooth Core Specification version 5.0 brought many feature enhancements like larger payload size, options for longer range, larger number of channels used, as compared to legacy advertisements introduced in version 4.0. Based on real-time energy consumption analysis, this paper deems Bluetooth Low Energy (BLE) extended advertisements as the more energy-efficient choice as compared to legacy advertisements for applications with motion data generated at high sampling rates, and also highlights the range of data size for which legacy advertisements are more energy-efficient. For sensor networks using high data sampling rates, taking receiving link layer’s behavior into account, the paper analysis the merits and demerits of utilizing all 1650 bytes of an extended advertising event which is the maximum allowed limit. Extensive real-time experimentation carried out for varying amount of network congestion reveals that data loss mostly remains between 2-4% even in highly congested channel for large amount of data sent in each extended advertising event. However, because receiving link layer rejects partially received extended advertising events, sometimes, hiked losses are observed. Sending smaller data in each event yields more stable losses across the sensor network, but these losses are larger in higher network congestion, and energy efficiency is poorer. The paper highlights the potential and limitations of extended advertisements in applications under consideration, and emphasizes the need of the receiving link layer’s capability to process partially received secondary channel packet chains.