Multi-AP Collaborative Sounding for Interference Nullification
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Solution Overview
Problem
In Multi-AP (MAP) wireless networks, interference between multiple wireless access points (APs) and stations (STAs) hampers efficient data transmission, necessitating an effective method to determine channel state information for efficient beamforming and mitigate interference.
Innovation Solution
A collaborative channel sounding measurement phase is introduced, utilizing null data packets (NDPs) and a sounding protocol that includes a measurement phase and feedback report phase to determine channel state information between STAs and APs, enabling efficient beamforming and interference nullification between channels.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If multiple wireless APs transmit concurrently in a MAP wireless network, then network efficiency and performance are improved, but interference between APs and STAs increases
Solution Approach 1:
The patent converts the harmful interference between multiple APs and STAs into useful channel state information through the sounding protocol. By having STAs measure and report interference characteristics, the system transforms adverse interference into data that enables beamforming optimization, allowing APs to adjust their transmission to nullify interference while maintaining concurrent operation
Solution Approach 2:
The patent implements a feedback mechanism where STAs measure the interference from multiple APs and report this information back to the coordinating AP. This feedback loop enables the system to continuously optimize beamforming weights based on actual channel conditions, allowing concurrent transmissions to proceed with minimal interference through iterative refinement of transmission parameters
2Object-generated harmful factors
If beamforming is applied to mitigate interference, then interference between channels is reduced, but channel state information must be continuously updated
Solution Approach 1:
The patent performs preliminary channel sounding before concurrent transmissions begin. The sounding protocol collects channel state information in advance, allowing beamforming weights to be pre-calculated and applied. This preliminary action ensures that interference mitigation is already in place before data transmission starts, eliminating the need for continuous updates during active transmission
3Object-generated harmful factors
If collaborative beamforming is performed based on up-to-date channel state information, then interference is prevented or reduced, but the complexity of the sounding protocol increases
Solution Approach 1:
The patent merges the channel sounding functionality into the existing Multi-AP coordination framework. Rather than implementing a separate complex sounding mechanism, the protocol integrates channel measurement and reporting into the existing beamforming setup procedures, sharing computational resources and signaling channels with the coordinated transmission management already in place
Data Source
AI summary
Embodiments of the present invention provide an apparatus and method for a MAP wireless network that includes a collaborative channel sounding measurement phase to determine channel state information between devices (e.g., the channel state between an STA and a collaborative AP) for efficient configuration of the MAP wireless network and to improve the performance of the MAP wireless networks. The wireless AP and wireless STAs associated with the collaborative APs can simultaneously transmit by applying collaborative beamforming where the interferences between channels nullify each other (e.g., nulling), and the beamforming is performed based on a sounding phase performed by the collaborative APs.