Wi-Fi Beacon Timing Synchronization for Power Reduction
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Solution Overview
Problem
WiFi applications on cellular devices are power-intensive due to low synchronization levels in Wi-Fi systems, leading to inefficient power consumption, especially during passive mode, as they require frequent monitoring for activity from other devices.
Innovation Solution
The method involves achieving timing synchronization with an external timing signal, such as GPS, through a mobile communications device that does not have a direct receiver for the signal by using a first Wi-Fi beacon to propagate timing information, allowing devices with and without a GPS receiver to synchronize, thereby extending network synchronization and reducing monitoring time and power consumption.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If devices monitor for activity from other devices frequently to maintain network synchronization, then synchronization level is improved, but power consumption increases
Solution Approach 1:
The patent implements periodic monitoring instead of continuous monitoring by establishing sleep intervals during which the device does not monitor for activity. Devices wake at scheduled intervals to check for activity and then return to sleep, reducing power consumption while maintaining synchronization through periodic updates from master devices that do have GPS receivers.
Solution Approach 2:
The patent introduces master devices with GPS receivers as intermediaries that obtain timing information directly from GPS and propagate it to slave devices without GPS receivers. This intermediary approach allows slave devices to achieve synchronization indirectly through periodic updates from masters, enabling longer sleep intervals without losing synchronization.
2Use of energy by moving object
If devices increase sleep time to reduce power consumption, then power consumption is reduced, but synchronization level deteriorates
Solution Approach 1:
The system establishes periodic sleep intervals for slave devices that are synchronized to GPS timing. Devices sleep for extended periods and wake only at scheduled intervals to receive synchronization updates from master devices, then return to sleep. This periodic operation maintains synchronization while enabling significant power savings through extended sleep time.
Solution Approach 2:
The patent implements a feedback mechanism where master devices monitor for activity from slave devices and provide synchronization updates in response. When slave devices wake and indicate presence, masters provide timing information to maintain synchronization, then devices can return to sleep. This feedback loop ensures synchronization is maintained even with extended sleep intervals.
3Measurement precision
If devices without GPS receivers attempt to synchronize directly with GPS, then synchronization accuracy is improved, but device complexity increases
Solution Approach 1:
The patent assigns the GPS reception function to master devices that have GPS receivers, while slave devices without GPS receivers obtain timing information indirectly from these masters. This intermediary approach allows slave devices to achieve GPS-level synchronization accuracy without requiring GPS hardware, maintaining precision while avoiding the complexity of GPS receivers in all devices.
Solution Approach 2:
The patent creates a universal synchronization system where master devices perform the dual function of both slave devices (participating in the network) and GPS receivers (obtaining timing information). This multi-functionality allows the system to achieve high synchronization accuracy for all devices without requiring every device to have GPS capability, reducing overall system complexity while maintaining precision.
Data Source
AI summary
Various methods and apparatus are directed to achieving timing synchronization and propagating timing information pertaining to an external, e.g., non Wi-Fi, timing signal source. In some embodiments, a mobile communications device receives and processes a timing signal, e.g., a first Wi-Fi beacon, which is propagating timing information about an external timing signal from a device which directly received the external timing signal. Thus, a mobile wireless communications device achieves timing synchronization with respect to an external timing signal which it is unable to receive directly. In various embodiments, the mobile communications device may, and sometimes does, further propagate the timing information about the external timing signal, e.g., via a second Wi-Fi beacon signal which it generates and transmits. Synchronization with respect to an external signal source facilitates longer sleep states and decreased power consumption.