WLAN Interface Wake-Sleep Control for Traffic-Aware Power Saving
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Solution Overview
Problem
IEEE 802.11-based WLAN NIDs face challenges in balancing power savings and performance, particularly for downlink applications where round trip time information is unknown, leading to degraded quality of service due to inefficient power management.
Innovation Solution
A smart power management scheme that adaptively wakes and sleeps the NID based on traffic arrival patterns, using beacon listen intervals divided into time slots, where the NID remains awake if data exceeds a threshold and sleeps otherwise, with adjustments made after each interval based on packet reception ratios.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the NID operates in constant active mode to maintain good application performance, then packet throughput and latency are improved, but power consumption increases significantly
Solution Approach 1:
The NID dynamically transitions between active and sleep states based on real-time traffic conditions. The system monitors packet arrival patterns and adjusts its operational state accordingly, being active when traffic is detected and sleeping when the medium is idle, thus optimizing both performance and power consumption dynamically
Solution Approach 2:
The system uses feedback from the wireless medium status and packet arrival patterns to control NID state transitions. By monitoring whether the medium is busy or idle and adjusting the NID state based on this feedback, the system achieves adaptive power management that maintains performance while reducing power consumption
2Use of energy by moving object
If the NID operates in power saving mode to reduce power consumption, then energy usage is reduced, but application performance degrades due to data delays
Solution Approach 1:
The system performs preliminary checks of the wireless medium status before the NID transitions to sleep mode. By verifying that the medium is idle and no packets are pending transmission, the system ensures that sleeping will not cause data delays, thus maintaining performance while enabling power savings
Solution Approach 2:
The system continuously monitors traffic patterns and medium status to provide feedback for state transition decisions. This feedback mechanism ensures that the NID only enters sleep mode when it is safe to do so without impacting performance, resolving the contradiction between power savings and performance
3Use of energy by moving object
If the NID awakens periodically in power saving mode, then power consumption is reduced, but quality of service degrades due to lack of correlation between wake times and data delivery times
Solution Approach 1:
The system dynamically adjusts the NID wake schedule from fixed periodic intervals to variable intervals based on actual traffic conditions. By making the wake schedule dynamic and responsive to medium status, the system maintains QoS reliability while achieving power savings through selective sleeping
Data Source
AI summary
Computer-implemented methods for power management of network interface devices are disclosed. Such methods may include dividing a time period into a plurality of time slots, determining an amount of data received by the network interface device during a first of the time slots, and determining whether the amount of data received exceeds a predefined threshold. If the amount of data received exceeds the predefined threshold, then the network interface device is caused to be awake during a subsequent time slot. The network interface device is caused to go to sleep during the subsequent time slot unless the amount of data received exceeds the predefined threshold. A number of the time slots may be defined as wakeup time slots during which the network interface device is awake. The number of time slots during the time period in which one or more packets were received by the network interface device may be compared to the number of wakeup time slots during the time period. Based on the comparison, the number of wakeup time slots may be adjusted for a subsequent time period.