Nulling Wireless Nodes for Distributed MIMO Interference
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Solution Overview
Problem
In wireless communication systems, especially those employing multiple-input multiple-output (MIMO) technology, there is a need for effective techniques to manage interference between devices sharing the same communication resource, particularly in scenarios where beamforming is used, as transmissions can interfere with each other even when directed differently.
Innovation Solution
The implementation of a system that determines which wireless nodes need to perform a nulling operation based on signal measurement information, generating a list to identify nodes that should null others to mitigate interference, and transmitting this list for coordinated beamforming and scheduling purposes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If multiple wireless nodes transmit on a shared communication resource using beamforming, then communication capacity and resource utilization are improved, but interference between transmissions increases
Solution Approach 1:
The patent applies preliminary anti-action by performing nulling operations before transmissions occur. The system identifies potential interferers in advance and configures beamforming weights to create nulls in the directions of these interferers, preventing interference from occurring in the first place rather than attempting to mitigate it after the fact.
Solution Approach 2:
The patent implements local quality by making the beamforming characteristics direction-dependent. Different spatial directions have different transmission qualities - directions toward intended receivers have high gain while directions toward potential interferers have nulls (zero gain). This allows the system to optimize performance locally in different spatial zones simultaneously.
2Object-generated harmful factors
If nulling operations are performed to reduce interference, then interference levels are reduced, but system complexity increases
Solution Approach 1:
The patent applies segmentation by dividing the nulling operation into distinct functional modules: signal measurement information acquisition, node identification based on interference criteria, nulling weight calculation, and beamforming application. This modular approach makes the complex nulling operation more manageable and implementable in practical systems.
Solution Approach 2:
The patent uses signal measurement information as an intermediary between the physical channel conditions and the nulling operation. Rather than directly computing complex nulling weights from raw channel state information, the system first processes this information through measurement and analysis stages, creating an intermediate representation that simplifies the subsequent nulling weight calculation.
3Productivity
If beamforming directions are optimized to improve communication efficiency, then throughput is improved, but interference management becomes more difficult
Solution Approach 1:
The patent merges the beamforming optimization and interference management functions into a unified process. Rather than separately optimizing beamforming directions for throughput and then adding interference mitigation, the system jointly optimizes both objectives simultaneously through coordinated nulling operations, achieving both goals through a single integrated approach.
Solution Approach 2:
The patent implements feedback by using signal measurement information from the wireless channel to continuously adjust nulling weights. The system monitors channel conditions and interference levels, then adapts the beamforming nulls accordingly, creating a closed-loop control system that maintains optimal performance despite changing conditions.
Data Source
AI summary
Various aspects of the disclosure relate to distributed multiple-input multiple-output (MIMO) communication such as coordinated beamforming or Joint MIMO. In some aspects, distributed MIMO is used to support communication in a cluster of wireless nodes (e.g., access points). A distributed MIMO scheduling scheme as taught herein is used to determine each wireless node (e.g., station) in the cluster that needs to be nulled by another wireless node (e.g., an access point). For example, one of the wireless nodes may obtain signal measurement information from the other wireless nodes and thereby generate a list of wireless nodes (e.g., access points) that need to null one or more wireless nodes (e.g., stations).