Dynamic Contention Mechanism for Random Resource Units in 802.11ax
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Solution Overview
Problem
The existing communication methods in wireless networks, particularly in 802.11ax networks, face inefficiencies in using random and scheduled resource units (RUs) due to collisions and underutilization, where nodes may collide on the same RU or leave RUs unused, leading to suboptimal bandwidth usage.
Innovation Solution
A method is introduced where the access point determines use statistics of random RUs and adjusts a TBD parameter to drive nodes in defining their contention window size, allowing for dynamic adaptation of contention schemes based on efficiency metrics, such as collision and unuse factors, to optimize RU usage and reduce collisions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If nodes use random resource units for transmission, then bandwidth utilization can be improved, but collisions between nodes on the same RU increase
Solution Approach 1:
The patent implements dynamic adjustment of the contention window size based on channel conditions and traffic load. The access point monitors the channel and adjusts the contention window parameter to optimize RU allocation, making the system adaptive rather than static. This resolves the contradiction by allowing high bandwidth utilization when conditions are good while reducing collisions when the channel is congested.
Solution Approach 2:
The patent changes key parameters including contention window size, RU allocation patterns, and transmission power levels to optimize performance. By dynamically adjusting these parameters based on channel conditions, the system can maximize bandwidth utilization while keeping collision probability within acceptable limits. The access point modifies these parameters in response to observed channel usage and collision patterns.
2Ease of operation
If nodes use fixed contention window size, then access mechanism is simple, but RU usage efficiency decreases due to collisions and underutilization
Solution Approach 1:
The access point implements a feedback mechanism where it monitors RU usage patterns, collision rates, and channel occupancy. Based on this feedback, the access point adjusts the contention window size and RU allocation for subsequent transmission opportunities. This feedback loop enables the system to improve RU usage efficiency while maintaining operational simplicity at the node level.
Solution Approach 2:
Each node autonomously determines its backoff counter based on the contention window size provided by the access point, without requiring complex centralized coordination. The access point simply provides the contention window parameter, and nodes self-manage their access timing. This self-service approach maintains simplicity while improving efficiency through dynamic parameter adjustment.
3Quantity of substance
If more random resource units are allocated, then available bandwidth increases, but the likelihood of collisions and unused RUs increases
Solution Approach 1:
The system dynamically adjusts the number of random RUs allocated based on the number of active nodes and channel conditions. When traffic load is high, more RUs are allocated to increase bandwidth capacity. When the number of nodes is low, fewer RUs are allocated to reduce the probability of collisions and underutilization. This dynamic allocation resolves the contradiction between providing abundant bandwidth and maintaining reliable usage.
Data Source
AI summary
In an 802.11ax network with an access point, a trigger frame offers random resource units to nodes for data uplink communication to the access point. To dynamically adapt the contention mechanism used by the nodes to access the random resource units, the AP updates a correcting TBD parameter at each new TXOP and includes the updated adjusting parameter in the trigger frame for the next TXOP. The nodes use the TBD parameter to generate a local random RU backoff value from a contention window range, for contending for access to the random resource units. The TBD parameter may directly impact the contention window size CWO or boundaries values of a selection range from which CWO is selected.