Bluetooth Controller Null PDU RSSI Proximity Detection
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Solution Overview
Problem
Bluetooth Low Energy (BLE) devices face high power consumption and rapid battery depletion due to frequent data exchange for maintaining connections, particularly when performing proximity measurements using Received Signal Strength Indicator (RSSI) messages, which increases power consumption and reduces battery life.
Innovation Solution
Implementing the use of null PDUs to determine proximity, where RSSI values are buffered and processed by the BLE controller, allowing the host device to remain in an energy-saving mode, reducing the need for frequent ATT transactions and minimizing power consumption.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If frequent data exchange is performed to maintain connection between BLE devices, then connection reliability is improved, but power consumption increases and battery life decreases
Solution Approach 1:
The patent implements periodic connection events where null PDUs are exchanged at predetermined intervals to maintain connection reliability. Instead of continuous data exchange, the system uses periodic null PDU transmissions with RSSI measurements, allowing devices to enter low-power states between events while maintaining connection integrity.
Solution Approach 2:
The patent extracts the connection maintenance function from the host device and delegates it to the BLE controller. The controller independently handles null PDU exchanges and RSSI measurements, freeing the host to enter power-saving modes while connection reliability is maintained by the controller's autonomous operation.
2Measurement precision
If RSSI messages are exchanged frequently for proximity measurements, then measurement precision is improved, but power consumption increases and battery life decreases
Solution Approach 1:
The system performs RSSI measurements periodically during null PDU exchanges rather than continuously. By measuring RSSI at regular connection intervals and using historical data for proximity determination, the system achieves adequate measurement precision while minimizing power consumption through reduced measurement frequency.
Solution Approach 2:
The BLE controller pre-processes RSSI values from null PDU exchanges and buffers proximity information before host wake-up. This preliminary action allows the host to remain in low-power mode while the controller prepares measurement data, reducing the need for frequent host activations and overall power consumption.
3Reliability
If the host device processes ATT transactions frequently, then connection maintenance is improved, but power consumption increases
Solution Approach 1:
The patent extracts connection maintenance operations (null PDU exchanges and RSSI measurements) from the host device and assigns them to the BLE controller. The host only wakes up for authentication ATT transactions and proximity determination, while the controller autonomously maintains connections, significantly reducing host power consumption.
Solution Approach 2:
The BLE controller performs self-service by independently handling null PDU exchanges, RSSI measurements, and connection maintenance without requiring frequent host intervention. The controller serves itself for connection management tasks, allowing the host to remain in power-saving modes while connection reliability is maintained.
Data Source
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AI summary
The disclosure generally relates to a method, apparatus and a system for utilizing received signal strength indicator (RSSI) values obtained from null data packets exchanges between a pair of Bluetooth (BT) devices to determine whether to maintain BT connection. In one embodiment, the disclosure relates to a method for maintaining a BT connection between a host and a periphery device by receiving at a controller associated with a host device a plurality of null packets sent from the periphery device; determining a received signal strength (RSSI) value for each of the plurality of received nulled packets; and determining whether to maintain connection with the periphery device as a function of the determined RSSI values.