TXOP Limit Compensation via Contention Window Adjustment
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Solution Overview
Problem
Wireless communication networks face inefficiencies due to the limitations of transmit opportunity (TXOP) limits, leading to suboptimal utilization of network resources and increased overhead, particularly in cases where low physical layer data rates result in long transmissions.
Innovation Solution
Adjusting contention window (CW) backoff time values to compensate for TXOPs that exceed the set limit, allowing for fair and efficient use of network resources by aggregating the difference between TXOP utilization and the TXOP limit, and updating CW values based on this adjustment to ensure fair access and reduced overhead.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If TXOP limit is enforced strictly, then fairness among devices is improved, but network efficiency deteriorates due to increased overhead and fragmented transmissions
Solution Approach 1:
The patent implements dynamic CW adjustment that adapts based on TXOP utilization patterns. The system transitions from static TXOP limiting to dynamic compensation mechanisms where devices that efficiently utilize TXOPs are rewarded with smaller CW values, while devices with poor utilization receive larger CW penalties. This dynamic approach resolves the contradiction by making fairness conditional on actual network behavior rather than enforcing uniform limits.
Solution Approach 2:
The patent changes the parameter being controlled from fixed TXOP duration to variable CW backoff values. Instead of enforcing a hard TXOP limit, the system monitors actual TXOP utilization and adjusts the CW parameter for subsequent access attempts. This parameter transformation allows the system to achieve fairness through probabilistic access control rather than deterministic time limits, improving overall network efficiency.
2Productivity
If TXOP limit is increased to reduce overhead, then network efficiency is improved, but fairness among devices deteriorates due to unequal airtime usage
Solution Approach 1:
The patent implements a feedback loop where each device's TXOP utilization is monitored and fed back into the CW adjustment mechanism. Devices that consume excessive airtime receive CW penalties that reduce their future access probability, while efficient users receive rewards. This feedback system automatically balances network efficiency with fairness without requiring centralized control or predefined TXOP limits.
Solution Approach 2:
The system dynamically adjusts CW values based on real-time observation of TXOP utilization patterns. Rather than setting fixed TXOP limits, the system allows transmissions to proceed and then adjusts access parameters based on actual resource consumption. This dynamic approach enables the network to achieve both efficiency (by allowing sufficiently long transmissions) and fairness (by penalizing excessive usage in subsequent access attempts).
3Ease of operation
If multiple short transmissions are used within TXOP limit, then fairness is improved, but overhead increases and efficiency deteriorates
Solution Approach 1:
The patent allows devices to occasionally exceed the nominal TXOP limit when it results in better overall network utilization. Rather than strictly enforcing multiple short transmissions, the system permits longer transmissions that can amortize overhead more effectively, provided that fairness is maintained through CW adjustment. This partial relaxation of the transmission limit resolves the contradiction by accepting some excess action (longer transmissions) in exchange for reduced overhead and improved efficiency.
4Device complexity
If TXOP limit is set to zero for certain transmissions, then simplicity is improved, but transmission efficiency deteriorates due to repeated backoff and access attempts
Solution Approach 1:
The patent extracts the TXOP limit concept from the access control mechanism and replaces it with CW-based compensation. Instead of managing complex TXOP timing and limits for different transmission types, the system simply monitors actual airtime usage and adjusts CW values accordingly. This extraction of the limit concept simplifies the mechanism while maintaining or improving transmission efficiency through the reward-penalty approach.
Data Source
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AI summary
Methods, systems, and devices are described for efficient use of transmit opportunities (TXOPs) through adjustment of contention window backoff time values to compensate for one or more TXOPs that may exceed a TXOP limit. A contention window value may be increased, for example, to provide other devices in the network with a fair opportunity for network access based at least in part on one or more TXOPs that exceed the TXOP limit. Allowing one or more transmissions to exceed a TXOP limit may provide enhanced efficiency as compared to having multiple transmissions.