Seamless handover of Bluetooth® LE connections for enhanced vehicle access user experience

Modern connectivity systems, such as automotive digital key platforms, rely on multiple wireless anchor nodes to cover an access environment for mobile tags like smartphones or key fobs. These nodes enable accurate ranging and localization of tags using UWB, Bluetooth RSSI, or channel sounding technologies by maintaining a continuous point to point Bluetooth LE connection with moving tags. In real-world scenarios, however, connection stability is often compromised when the tag moves away from its connected anchor node, resulting in link degradation, disconnection, and the need to re-establish connection with another node. This disconnect/reconnect cycle negatively impacts responsiveness and user experience.

This paper presents a novel system-level solution for seamless Bluetooth LE connection handover between anchor nodes. The proposed approach enables an active connection to migrate to a node with a superior link budget – without the smartphone tag being aware of the transition. From the tag’s perspective, the connection remains uninterrupted, addressing a critical gap in current Bluetooth specification, which does not support native connection handover.

We detail innovations at both the Bluetooth stack and multi-anchor system architecture levels, using automotive digital key car access systems as a representative use case. The paper also presents performance metrics based on connection handover implementation using Texas Instruments Bluetooth LE devices and software stack.

Learn more on how to apply these insights to your own products.