WLAN Power Management via Predictive Beacon Scanning
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Solution Overview
Problem
Traditional WLAN devices consume excessive power due to brute-force channel scanning techniques, which can deplete battery life quickly, especially when performing frequent RSSI scans for location services.
Innovation Solution
Implementing a fast scanning technique that calculates and predicts upcoming beacon times to reduce the duration of RSSI scans from 50-100 ms to a few milliseconds, and only scanning a subset of frequently used channels, while maintaining compliance with existing IEEE 802.11x standards.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If traditional brute-force channel scanning techniques are used to perform RSSI scans, then comprehensive channel coverage and reliable location services are achieved, but power consumption increases excessively
Solution Approach 1:
The patent segments the channel scanning process by dividing channels into two categories: frequently used channels and less frequently used channels. The device performs rapid scanning on frequently used channels to maintain location services, while reducing or skipping scans on less frequently used channels. This segmentation allows the system to achieve reliable location services through focused scanning of relevant channels while significantly reducing overall power consumption compared to traditional brute-force scanning of all channels.
2Measurement precision
If frequent RSSI scans are performed to maintain location services, then location accuracy is improved, but battery life is depleted quickly
Solution Approach 1:
The patent implements periodic scanning actions with varying frequencies based on channel importance. Instead of uniform frequent scanning of all channels, the system performs periodic scans on frequently used channels at higher intervals to maintain location accuracy, while performing scans on less frequently used channels at lower intervals or only when necessary. This periodic action with differentiated frequencies maintains measurement precision for location services while extending battery life by avoiding continuous high-frequency scanning of all channels.
3Measurement precision
If RSSI scan duration is extended to ensure accurate signal strength measurement, then measurement precision is improved, but power consumption increases
Solution Approach 1:
The patent applies partial action by performing rapid, shortened scans on frequently used channels rather than executing full-duration scans on all channels. The scan duration and depth are adjusted based on channel priority - frequently used channels receive quicker scans that capture essential signal strength information, while less frequently used channels receive minimal or deferred scanning. This partial action approach maintains sufficient measurement precision for location services on critical channels while reducing overall power consumption by avoiding exhaustive scanning of all channels.
Data Source
AI summary
Methods and apparatus to manage power consumption in wireless devices are disclosed. A disclosed example apparatus comprises performing a first received signal strength indicator (RSSI) scan to determine a beacon interval and a first beacon time for a wireless channel, calculating a second beacon time for the wireless channel based on the beacon interval and the first beacon time, and performing a second RSSI scan for the wireless channel during a time interval that includes the calculated second beacon time. In some examples, the wireless channel is a wireless channel that was previously identified as active, is a wireless channel that previously had the highest received power level, and/or is selected from a list of popular or frequently used channels. Additionally or alternatively, when a wireless channel with sufficient signal level is identified, scanning for additional channels is not performed.