Coordinated Beamforming in WLAN OBSS for Interference Reduction
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Solution Overview
Problem
Wireless Local Area Networks (WLANs) in overlapping basic service sets face interference issues due to simultaneous transmission limitations, which restrict area throughput and hinder efficient implementation of coordinated beamforming.
Innovation Solution
A method and system enabling coordinated beamforming in WLANs by allowing access points to exchange channel state information and maintain a CB table, facilitating simultaneous transmissions through periodic announcement messages and CSI requests, thereby reducing interference.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If CSMA/CA is used for medium access control in WLAN, then devices can share unlicensed spectrum resources, but simultaneous transmissions are limited and area throughput is restricted
Solution Approach 1:
The patent introduces beamforming as an intermediary mechanism that enables simultaneous transmissions by directing signals spatially. Access points use beamforming to create directed beams toward intended recipients, which acts as a mediator to manage interference between concurrent transmissions in overlapping basic service sets.
Solution Approach 2:
The patent changes the transmission parameter from omnidirectional broadcasting to directional beamforming. By adjusting the spatial distribution of transmitted energy through beamforming, the system enables multiple access points to transmit simultaneously while controlling interference levels, thereby improving area throughput.
2Productivity
If beamforming is implemented in WLAN OBSS scenarios, then simultaneous transmissions are enabled, but system complexity increases due to coordination requirements
Solution Approach 1:
The patent implements preliminary action by having access points exchange coordination information and establish beamforming parameters before simultaneous transmissions begin. The system performs channel state information gathering and beamforming configuration in advance, which simplifies the actual transmission coordination and reduces operational complexity.
Solution Approach 2:
The patent employs feedback mechanisms where access points monitor transmission quality and interference levels, then adjust beamforming parameters accordingly. This feedback loop enables automatic adaptation to changing conditions, reducing the need for complex manual coordination and simplifying system operation.
3Productivity
If multiple access points transmit simultaneously in OBSS, then area throughput increases, but interference management becomes more difficult
Solution Approach 1:
The patent applies local quality by directing beamforming energy specifically toward intended recipient stations rather than broadcasting omnidirectionally. Each access point tailors its transmission characteristics locally to its target STA, creating focused beams that minimize interference to other stations in overlapping basic service sets while maintaining high throughput.
Data Source
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AI summary
Embodiments are provided for enabling a beamforming mechanism in WLAN OBSSs. In an embodiment, a first AP of the OBSSs decides to participate in coordinated beamforming for the OBSSs. The OBSSs comprise a plurality of APs and a plurality of STAs associated with the APs. The AP thus transmits, periodically, a coordinated beamforming (CB) announcement message indicating an ID of the first AP and an ID of each STA associated with the first AP. When a second AP of the OBSSs receives the message from the first AP, the second AP maintains the ID of the first AP and the ID of each STA associated with the first AP in an entry of a CB table. When the second AP stops receiving the message, the second AP removes, from the CB table, the entry of the IDs of the first AP and its associated STAs.