WLAN Frame Transmission via TWT Countdown Suspension

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Solution Overview

Problem

Next-generation WLAN systems face challenges in improving spectrum efficiency and area throughput, especially in dense environments with many access points and stations, and in outdoor settings where existing WLANs underperform due to interference and high user loads.

Innovation Solution

A method for transmitting frames in a WLAN system involves a wireless terminal receiving beacon frames with parameter set information and timer information, performing a countdown operation based on a backoff counter, suspending it until a Target Wake Time (TWT) service period expires, and resuming the countdown for the remaining time in a subsequent TWT service period, optimizing channel access in multi-user uplink transmission.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Speed

If a wireless terminal continuously performs countdown operation for channel access, then channel access responsiveness is improved, but power consumption increases and performance degrades in outdoor environments

Engineering Contradiction:

Improvechannel access responsivenessVSAvoidpower consumption

Core Design Contradiction:

SpeedVSUse of energy by moving object

Solution Approach 1:

The patent implements periodic Target Wake Time (TWT) service periods where the wireless terminal wakes up at scheduled intervals to perform countdown operations for channel access. Instead of continuous operation, the terminal suspends countdown during non-TWT periods and resumes only during active TWT service periods, creating a periodic action pattern that reduces power consumption while maintaining channel access responsiveness when needed.

Inventive Principle:

Principle #19Periodic action

Solution Approach 2:

The patent performs preliminary setup by establishing multiple TWT service periods in advance with scheduled wake times. The wireless terminal pre-configures its countdown operation to align with these predetermined service periods, allowing it to suspend and resume countdown operations at planned intervals rather than continuously operating, thereby reducing energy consumption while ensuring timely channel access when required.

Inventive Principle:

Principle #10Preliminary action

2Use of energy by moving object

If countdown operation is suspended during TWT service period, then power consumption is reduced, but channel access delay increases

Engineering Contradiction:

Improvepower consumptionVSAvoidchannel access delay

Core Design Contradiction:

Use of energy by moving objectVSLoss of time

Solution Approach 1:

The patent dynamically adjusts the countdown operation based on the TWT service period status. The wireless terminal suspends countdown during non-TWT periods to save power and resumes it during active TWT service periods to ensure timely channel access. This dynamic adjustment allows the system to optimize the trade-off between power consumption and channel access delay by adapting the countdown behavior to current operational conditions.

Inventive Principle:

Principle #15Dynamics

Solution Approach 2:

The patent uses TWT service period information as feedback to control the countdown operation. The wireless terminal monitors whether it is currently in an active TWT service period and uses this feedback to decide whether to suspend or resume the countdown operation. This feedback mechanism ensures that countdown is active only when needed, preventing unnecessary delays while minimizing power consumption during inactive periods.

Inventive Principle:

Principle #23Feedback

3Ease of operation

If countdown is resumed in subsequent TWT service period, then channel access fairness is improved, but remaining time calculation complexity increases

Engineering Contradiction:

Improvechannel access fairnessVSAvoidtimer management complexity

Core Design Contradiction:

Ease of operationVSDevice complexity

Solution Approach 1:

The patent implements a self-service mechanism where the wireless terminal automatically calculates and adjusts its remaining countdown time when resuming in a subsequent TWT service period. The terminal subtracts the elapsed time from the original countdown value and continues decrementing from this adjusted value. This self-service approach ensures fair channel access by maintaining consistent countdown logic across multiple TWT service periods while minimizing the need for complex external timer management.

Inventive Principle:

Principle #25Self-service

Data Source

PatentUS10206230B2Method for transmitting frame in wireless local area network and wireless terminal using the same

Publication Date: 2019.02.12 LG ELECTRONICS INC

AI summary

A method for transmitting a frame, performed by a first wireless terminal, in a WLAN system according to one embodiment includes: receiving, from a second wireless terminal, a beacon frame including first parameter set information for first channel access of a plurality of user terminals participating in multi-user uplink transmission, timer information indicating an allowed time allowed for the first parameter set information, first TWT information for a first TWT service period, and second TWT information for a second TWT service period; performing a countdown operation based on a backoff counter set according to the first parameter set information when a trigger frame for individually allocating a plurality of radio resources is received in the first TWT service period; suspending the countdown operation when the countdown operation is not completed until the first TWT service period expires; and resuming the countdown operation when the second TWT service period starts.