STA Power Save Mode Using Overheard BSS Information
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Solution Overview
Problem
In wireless local area networks (WLANs), stations (STAs) operating in power save mode face challenges in maintaining reduced power consumption while efficiently managing pending frames, as they need to periodically transition from a doze state to an awake state to receive information about pending frames, which affects their lifespan and operational efficiency.
Innovation Solution
The method involves an STA receiving overhear BSS information from an access point (AP), determining if this information includes data on other BSSs that can transmit frames that can be overheard by the AP, and transitioning to a doze state based on this information, allowing for power savings and extended operational time by predicting when frames from other BSSs are received.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If the STA operates in the doze state to reduce power consumption, then power consumption is reduced and lifespan is increased, but frame transmission or reception becomes impossible and the STA cannot receive pending frames from the AP
Solution Approach 1:
The AP transmits information about pending frames to the STA before the STA actually needs to receive them, using beacon frames with TIM/DTIM elements. This allows the STA to plan its awake/doze transitions in advance, reducing unnecessary wake-ups while ensuring frame reception capability.
Solution Approach 2:
The system uses a feedback mechanism where the AP monitors which STAs have pending frames and communicates this information back to those STAs through beacon frames. The STAs then adjust their power save mode operations based on this feedback, creating a closed-loop system that balances power saving with frame reception reliability.
2Reliability
If the STA periodically transitions to the awake state to receive beacon frames and check for pending frames, then the STA can receive pending frames from the AP, but power consumption increases and operational efficiency decreases
Solution Approach 1:
The system uses periodic beacon frame transmission at defined intervals (beacon interval) with optional DTIM periods for multicast/broadcast frames. This structured periodic approach allows STAs to synchronize their awake periods with beacon transmissions, reducing unnecessary wake-ups while ensuring timely delivery of pending frames.
3Reliability
If the STA stays in the awake state to ensure continuous frame transmission and reception capability, then frame communication reliability is maintained, but power consumption increases and lifespan is reduced
Solution Approach 1:
The STA dynamically adjusts its operational state between awake and doze modes based on real-time conditions, particularly the presence of pending frames indicated by TIM/DTIM elements in beacon frames. This dynamic state transition allows the system to maintain full functionality when needed while maximizing power savings during periods without pending frames, thereby extending battery lifespan.
Data Source
AI summary
Disclosed are a power save mode-based operating method and apparatus in a wireless LAN. The power save mode-based operating method in a wireless LAN comprises the steps of: receiving, by an STA, overheard BSS information from an AP; receiving, by the STA, a PPDU, wherein the PPDU includes information on a BSS having transmitted the PPDU; determining, by the STA, whether the overheard BSS information includes the information on the BSS; and switching an awake state to a doze state when the STA determines whether the overheard BSS information includes the information on the BSS, wherein the overheard BSS information can include the information on at least one overheard BSS for transmitting a frame enabled to be overheard by the AP.