Wireless Station Power Saving via Frame Aggregation and Wakeup Control
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Solution Overview
Problem
Conventional power-saving modes in wireless communication systems, such as IEEE 802.11, are inefficient due to unpredictable wake-up times and high power consumption, especially when stations transition to sleep mode without receiving data, leading to prolonged wake-up times and increased transmission overhead.
Innovation Solution
The implementation of a power-saving apparatus and method that allows stations (STA) to wake up periodically or non-periodically, utilizing frame aggregation and control information frames to manage data transmission and reception, and transition to sleep mode based on recommended wake-up times from Access Points (AP), thereby optimizing power usage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If stations wake up periodically to check for data, then power consumption is reduced, but wakeup time becomes unpredictable and transmission overhead increases
Solution Approach 1:
The AP performs preliminary actions by buffering data for STAs before they wake up, and by proactively notifying STAs of buffered data availability. This allows STAs to wake up at predictable intervals knowing data may be available, reducing unnecessary wakeups while maintaining reliable data delivery.
Solution Approach 2:
The system implements feedback mechanisms where STAs report their wakeup status and data reception status to the AP, and the AP responds with buffered data availability information. This feedback loop enables dynamic adjustment of wakeup schedules, improving both power efficiency and wakeup time predictability.
2Speed
If stations remain in active mode to receive data quickly, then data transmission speed is improved, but power consumption increases
Solution Approach 1:
The system dynamically adjusts STA operational states between active and sleep modes based on real-time data availability. STAs transition to active mode only when data is actually available at the AP, and remain in sleep mode when no data is buffered, optimizing the balance between transmission speed and power consumption.
Solution Approach 2:
STAs employ periodic wakeup cycles to check for buffered data at the AP, rather than remaining continuously active. This periodic action allows STAs to maintain sleep mode for extended periods (saving power) while still enabling timely data reception when data arrives, achieving both power efficiency and acceptable transmission speed.
3Use of energy by moving object
If stations send null frames to indicate wakeup, then power-saving operation is maintained, but transmission overhead increases
Solution Approach 1:
The patent extracts and eliminates the null frame mechanism from the power-saving protocol. Instead of requiring STAs to send null frames to indicate wakeup or data receipt, the system uses direct data frame transmissions and AP-initiated buffered data notifications, removing unnecessary control frames and reducing transmission overhead.
Solution Approach 2:
The AP performs self-service by automatically tracking which STAs have buffered data and proactively notifying them, eliminating the need for STAs to send probe null frames to check for data. This self-service approach reduces STA transmission overhead while maintaining reliable data delivery.
Data Source
AI summary
A power saving apparatus and a method in a wireless communication system are provided. An Access Point (AP) buffers transmission frames for sleep-mode stations in a sleep-mode buffer. Upon wakeup from a sleep mode, a station sends a first control information frame indicating wakeup to the access point. The access point sends a second control information frame including a requested transmission length in response to the first control information frame to the station. The station generates a third control information frame, aggregates the third control information frame and user data frames to a first protocol data unit, and sends it to the AP. Then the AP generates a fourth control information frame, aggregates the fourth control information frame and buffered frames to a second protocol data unit, and sends it to the station.