WLAN Power Management via Beacon Time Slicing
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Solution Overview
Problem
Current power saving mechanisms in IEEE 802.11 wireless local area networks are inefficient, leading to excessive power consumption due to unpredictable awake periods, inadequate differentiation between multicast and broadcast frames, and unnecessary energy usage in multicasting environments.
Innovation Solution
The introduction of a time slicing scheme within the TIM structure, where the access point divides the beacon interval into fixed-length time slices and transmits information about the transmission timing for each station, allowing stations to wake up only when their frames are scheduled for transmission, thereby optimizing power management and reducing unnecessary active periods.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If stations wake up periodically to check for buffered frames, then power consumption is reduced, but networking performance degrades due to unpredictable awake periods
Solution Approach 1:
The beacon interval is segmented into multiple time slices, with each time slice dedicated to serving specific stations. This segmentation allows stations to know exactly when to wake up for frame retrieval, eliminating unpredictable awake periods while maintaining power savings.
Solution Approach 2:
The access point performs preliminary scheduling of frame transmissions by dividing the beacon interval into time slices and assigning specific time slots to stations with buffered frames. This preliminary action enables stations to wake up at predetermined times rather than remaining awake unpredictably.
2Use of energy by moving object
If the access point buffers frames for power saving mode stations, then power consumption is reduced, but device complexity increases
Solution Approach 1:
The access point buffers frames in a structured manner organized by time slices and station identifiers. This segmented buffering approach simplifies the complexity by providing a systematic method for managing buffered frames, making the buffering process more manageable and less complex.
3Productivity
If stations stay awake to receive buffered frames, then networking performance is maintained, but power consumption increases
Solution Approach 1:
Stations wake up periodically at specific time slices predetermined by the access point's scheduling. This periodic action at controlled intervals maintains networking performance by ensuring timely frame reception while minimizing power consumption by keeping stations in sleep mode during non-scheduled periods.
Solution Approach 2:
The access point performs preliminary scheduling to determine exactly when each station needs to wake up for frame retrieval. This preliminary scheduling enables stations to wake up only when necessary, maintaining networking performance while avoiding unnecessary power consumption from extended awake periods.
4Ease of manufacture
If the access point uses traditional TIM structure, then implementation is simple, but power saving efficiency is insufficient
Solution Approach 1:
The traditional TIM structure is enhanced by segmenting the beacon interval into time slices and incorporating slicing information in the TIM element. This segmentation provides detailed timing information to stations, enabling more efficient power saving while building upon the existing simple TIM structure.
Solution Approach 2:
The TIM structure is made dynamic by incorporating time slice information that changes with each beacon interval. This dynamic enhancement allows the system to adapt to varying traffic patterns and station requirements, improving power saving efficiency while maintaining compatibility with the existing TIM framework.
Data Source
AI summary
A method and apparatus for improving power performance of a wireless adapter which adopts a time slicing scheme by dividing a beacon interval into multiple slices, and assigning these slices to the stations through the beacon frame. The stations wakeup at the appointed slices to receive their buffered frames from an access point, and may enter into sleep state once the transactions conclude. A further embodiment including formatting data into a control frame for use in a wireless local area network, the frame including an indication, for each station associated with the wireless local area network, whether frames are buffered awaiting transmission to each respective station, a number of time intervals between control frames, and at which time interval the transmission of the buffered frames will begin for each station having buffered frames awaiting transmission.