Bluetooth Smart Scan Cache for Fast Device Connection
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Bluetooth device connection establishment is hindered by a time-intensive device discovery phase, particularly due to the lengthy inquiry scan process, which can lead to unacceptable delays for users waiting for connections to be established in Bluetooth Personal Area Networks (PANs).
Innovation Solution
Implementing an inquiry scan cache and a page scan cache, where the page scan cache is refreshed periodically and upon connection attempts, and the inquiry scan cache is updated when a remote device connects, allowing for a 'smart scan' that prioritizes page scanning for preferred devices, reducing the overall scanning time by combining results from both caches.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of time
If a traditional inquiry scan is performed to discover Bluetooth devices, then complete device discovery is achieved, but the connection establishment time becomes excessively long (up to 30.72 seconds)
Solution Approach 1:
The patent maintains a cache of previously discovered Bluetooth devices and their information. When a connection is needed, the system first checks this cache to see if the target device is already recorded, allowing immediate connection without performing a full inquiry scan. This preliminary action of caching device information dramatically reduces connection establishment time while maintaining reliability for frequently used devices.
Solution Approach 2:
The patent divides the device discovery process into two segments: a fast path using cached information for known devices, and a complete inquiry scan only when necessary for unknown devices. This segmentation allows the system to optimize for common cases (fast connection) while preserving the ability to handle edge cases (discovering new devices) when needed.
2Loss of information
If a complete inquiry scan is performed periodically, then all available Bluetooth devices are discovered, but the scanning time and energy consumption increase significantly
Solution Approach 1:
Instead of performing continuous or frequent complete inquiry scans, the patent implements periodic scanning only when necessary. The system uses cached device information between scans and only initiates a new inquiry scan when the cache needs refreshing or when connection attempts fail. This periodic action maintains device list accuracy while dramatically improving scanning efficiency and reducing energy consumption.
Solution Approach 2:
The patent creates and maintains a cached copy of device discovery information in memory. This copy allows the system to quickly access device information without repeatedly performing the full inquiry scan process. The cached copy is updated periodically or on-demand, balancing information accuracy with scanning efficiency.
Data Source
AI summary
A system and method for discovering and connecting to a preferred remote Bluetooth device by a local Bluetooth device. An inquiry scan cache and a page scan cache are maintained. The inquiry scan cache is updated by way of a periodic inquiry scan. The page scan cache is refreshed by way of an attempt to connect to the preferred remote Bluetooth device. Periodically, and more frequently than the periodic inquiry scan, a list of available remote Bluetooth devices is formed from entries in the inquiry scan cache concatenated with each entry in the page scan cache for which a page scan is successful. In one embodiment, the page scan cache holds a finite number of entries, and an expiration policy is applied to each added entry. In another embodiment, the inquiry scan cache is also updated when a remote Bluetooth device attempts to connect to the local Bluetooth device.