Access Point Beamforming for Uncoordinated WLAN Spatial Reuse
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Solution Overview
Problem
Existing WLAN systems struggle with low latency and real-time applications in scenarios involving multiple overlapped Basic Service Sets (BSSs) due to interference issues, as existing spatial reuse techniques require coordination and interference nulling that can reduce the AP's degrees of freedom and create overhead.
Innovation Solution
Introduce a training data unit to enable opportunistic beamforming without coordination, allowing access points to share channel state information and resource allocations with minimal cooperation, using beamforming techniques to determine spatial reuse opportunities.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If traditional spatial reuse techniques are used with coordination and interference nulling, then interference control is improved, but device complexity and overhead increase
Solution Approach 1:
Each access point independently performs beamforming based spatial reuse using its own channel state information and measurements, without requiring coordination with other access points. The system enables self-service operation where each AP autonomously determines spatial reuse opportunities and executes beamforming nulling locally, eliminating the need for complex inter-AP coordination protocols.
Solution Approach 2:
The patent extracts the essential functionality of spatial reuse and beamforming nulling from the coordinated multi-AP control mechanism and implements it at the individual AP level. Each AP independently performs the necessary beamforming calculations and interference nulling operations using locally available channel state information, separating the spatial reuse function from centralized coordination.
2Device complexity
If beamforming based spatial reuse is implemented without coordination, then device complexity is reduced, but measurement precision and interference control worsen
Solution Approach 1:
The patent performs preliminary channel sounding and measurement operations during dedicated time intervals before actual data transmission. Access points conduct preliminary beamforming calculations and interference measurements in advance, allowing them to pre-determine optimal beamforming weights and nulling directions for subsequent spatial reuse transmissions without requiring real-time coordination.
Solution Approach 2:
The system incorporates feedback mechanisms where stations report channel state information and interference measurements to their associated access points. This feedback loop enables each AP to continuously update its channel knowledge and adjust beamforming parameters, maintaining measurement precision through local feedback rather than coordinated multi-AP measurement protocols.
3Productivity
If interference nulling is performed, then spatial reuse efficiency is improved, but the access point's degrees of freedom are reduced
Solution Approach 1:
The patent applies beamforming nulling techniques locally at each access point independently, targeting interference directions specific to each AP's own stations. Each AP performs nulling only in directions where it transmits, leaving other spatial degrees of freedom available for future transmissions or other APs. This localized approach maintains adaptability while achieving interference control.
Data Source
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AI summary
A first access point comprises circuitry configured to perform a sounding procedure with one or more first stations associated with the first access point and configured to communicate with the first access point over a respective channel to determine resource unit allocation and beamforming configuration for use in subsequent communication with respective first stations, and to transmit a training data unit containing signaling information related to the determined resource unit allocation and related to the determined beamforming configuration, wherein the training data unit is transmitted with a beamforming configuration derived from the determined resource unit allocation and the determined beamforming configuration.