Periodic Restricted Access Window for Wi-Fi Power Savings
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Solution Overview
Problem
In IEEE 802.11ah wireless communication systems, long sleep stations face high power consumption due to the need to constantly wake up and listen for resource allocations, which shortens their battery life and reduces channel efficiency.
Innovation Solution
Implementing a periodic restricted access window (PRAW) where long sleep stations are assigned a designated time slot during association or reconfiguration, allowing them to exchange data without needing to listen for beacon frames, and broadcasting resource information only when necessary, thereby reducing unnecessary wake-ups and power consumption.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If long sleep stations constantly wake up to listen for resource allocations, then channel efficiency is maintained, but power consumption increases and battery life decreases
Solution Approach 1:
The patent implements periodic restricted access windows (PRAWs) where resource allocation occurs at specific periodic intervals rather than continuously. Stations wake up only during these predetermined periodic windows to receive resource allocations, then return to sleep mode. This periodic action maintains channel efficiency by ensuring regular resource distribution while dramatically reducing power consumption by limiting wake-up frequency.
Solution Approach 2:
The access point performs preliminary resource allocation and notification before the actual data transmission period. Resource allocation messages are sent in advance during the PRAW, allowing stations to prepare and enter sleep mode knowing when their next transmission opportunity will occur. This preliminary action eliminates the need for continuous monitoring while ensuring stations are ready for upcoming transmissions.
2Reliability
If resource allocation information is broadcast continuously, then all stations receive timely updates, but signaling overhead increases
Solution Approach 1:
The patent extracts resource allocation information from continuous broadcast streams and concentrates it into specific periodic intervals (PRAWs). Instead of embedding allocation messages in every beacon frame or control transmission, the system dedicates specific time windows solely for resource allocation notifications. This extraction reduces signaling overhead by eliminating redundant repeated transmissions while maintaining reliability through concentrated, periodic delivery.
Solution Approach 2:
Resource allocation broadcasting is transformed from a continuous process into a periodic action occurring only during designated PRAW intervals. The access point sends allocation information at regular periodic intervals rather than continuously, reducing the total volume of signaling traffic. Stations are configured to expect and monitor these periodic broadcasts, ensuring reliable information delivery without the overhead of continuous transmission.
3Loss of time
If long sleep stations wake up frequently to check for allocations, then resource allocation timeliness is improved, but battery life is reduced
Solution Approach 1:
The system establishes periodic restricted access windows at predetermined intervals that balance timeliness and power consumption. Rather than requiring stations to wake up continuously or at arbitrarily frequent intervals, the PRAWs provide regular periodic opportunities for resource allocation. This periodic structure ensures allocations occur in a timely manner relative to the periodic interval while extending battery life by keeping stations in sleep mode between intervals.
Solution Approach 2:
The patent implements dynamic PRAW configurations where the periodic interval and window duration can be adjusted based on traffic conditions and station requirements. The system can dynamically modify the frequency and length of wake-up periods to optimize the trade-off between allocation timeliness and power consumption. This dynamic adaptation allows the system to respond to changing conditions while maintaining the core benefit of reduced power consumption compared to continuous monitoring.
Data Source
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AI summary
A method for operating an access point includes broadcasting reservation information for a periodic group resource, assigning a resource in the periodic resource to a first station and transmitting information about the resource in the periodic group resource allocated to the first station to the first station, wherein the transmitting occurs during one of an association procedure with the first station and a reconfiguration of a resource assignment for the first station. The method also includes exchanging data with the first station during the resource in the periodic group resource allocated to the first station.