Adaptive OFDMA Backoff for Dense RA-RU Contention
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Solution Overview
Problem
In densely distributed scenarios, the probability for a station (STA) to successfully contend for an uplink orthogonal frequency division multiple access (OFDMA)-based random access resource unit (RA-RU) and transmit an UL physical layer protocol data unit (PPDU) to an access point (AP) is low.
Innovation Solution
The STA determines a target backoff value based on an orthogonal frequency division multiple access (OFDMA) backoff counter, a target coefficient, and a first resource unit number, and contends for a random access-RU using an OBO mechanism, with the target coefficient adaptively adjusted according to the number of participating STAs to alleviate collisions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If STAs contend for RA-RU based on traditional OBO mechanism, then the random access process is simple, but the probability of successful access is low in densely distributed scenarios
Solution Approach 1:
The patent changes the parameter of backoff value determination by introducing a target coefficient that multiplies the OBO counter value. Instead of using the OBO counter directly, the system calculates target backoff value = OBO counter × target coefficient, where the coefficient adapts based on the number of participating STAs. This parameter transformation allows dynamic adjustment of contention behavior to improve successful access probability while maintaining the basic OBO mechanism structure.
Solution Approach 2:
The patent introduces dynamic adaptation by making the backoff calculation dependent on the number of participating STAs. The target coefficient is adjusted dynamically based on network conditions (number of contending STAs), transforming the static backoff mechanism into a dynamic one that adapts to densely distributed scenarios, thereby improving successful access probability without requiring complete redesign of the access protocol.
2Object-affected harmful factors
If STAs use fixed backoff values, then the contention process is simple and fast, but collisions increase in densely distributed scenarios
Solution Approach 1:
The patent applies preliminary action by pre-defining target coefficients based on the number of participating STAs before the actual contention process. The system determines appropriate coefficient values in advance (e.g., different coefficients for different ranges of STA counts), so that during the contention process, STAs only need to multiply their OBO counter by the pre-determined coefficient rather than performing complex real-time calculations, thus reducing collision while minimizing time loss.
3Object-affected harmful factors
If the backoff step size is large, then STAs can avoid collisions more effectively, but the access speed decreases
Solution Approach 1:
The patent makes the backoff step size dynamic by using the target coefficient to scale the OBO counter value. When the number of participating STAs is large, the target coefficient increases the effective step size, spreading STAs more widely across the backoff range to reduce collisions. When fewer STAs are present, the coefficient is smaller, maintaining faster access speed. This dynamic scaling resolves the trade-off between collision avoidance and access speed.
Data Source
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AI summary
A method for wireless communication, a station (STA), and an access point (AP) are provided. The method includes the following. An STA determines a target backoff value based on a count value of an orthogonal frequency division multiple access (OFDMA) backoff (OBO) counter, a target coefficient, and a first resource unit (RU) number, where the first RU number is the number of RUs allocated to the STA by an AP. The STA contends for a random access-RU (RA-RU) based on an OBO mechanism according to the target backoff value.