Over-the-Air Beamforming Calibration for Distributed MIMO Systems
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Solution Overview
Problem
Existing beamforming calibration methods for multi-antenna transceiver systems face challenges such as high complexity in hardware/software for internal calibration networks, cumbersome signaling overhead in over-the-air methods, and incompatibility with distributed systems, especially those using analog or hybrid beamforming sub-systems.
Innovation Solution
A method for over-the-air beamforming calibration that selects pairs of transmission and reception beams from available sets across different beamforming sub-systems in a distributed MIMO system, performs sounding signal measurements, and determines calibration factors to reduce signaling overhead and improve scalability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If internal calibration network is used, then calibration accuracy is improved, but device complexity increases
Solution Approach 1:
The patent extracts the calibration process from the internal calibration network approach and implements it through over-the-air signaling between distributed beamforming sub-systems. This allows calibration without requiring complex internal calibration networks, reducing hardware and software complexity while maintaining calibration accuracy through external measurements.
Solution Approach 2:
The patent introduces over-the-air signaling as an intermediary mechanism between beamforming sub-systems for calibration purposes. Instead of direct internal calibration, the system uses external signaling resources to enable calibration measurements, thereby avoiding the complexity of internal calibration networks while achieving the desired calibration accuracy.
2Measurement precision
If existing over-the-air signaling methods are used, then calibration is achieved, but signaling overhead increases
Solution Approach 1:
The patent segments the calibration process into discrete measurement resources and beam pair combinations. By organizing calibration into structured segments with specific beam pairs and measurement resources, the system reduces redundant signaling and minimizes overhead while maintaining comprehensive calibration coverage.
Solution Approach 2:
The patent applies partial action by selecting only the necessary beam pairs and measurement resources required for calibration, rather than exhaustively using all possible combinations. This selective approach reduces signaling overhead while providing sufficient calibration accuracy for the distributed MIMO system.
3Measurement precision
If co-located multi-antenna systems calibration methods are applied, then calibration is achieved, but adaptability to distributed systems decreases
Solution Approach 1:
The patent designs a universal calibration framework that can be applied to both co-located and distributed multi-antenna systems. The over-the-air signaling approach with beam pair selection provides multi-functionality, enabling the same calibration method to work across different system configurations including distributed MIMO systems with analog and hybrid beamforming sub-systems.
Solution Approach 2:
The patent introduces dynamic adaptability by allowing the calibration method to adjust to different system configurations. The system can dynamically select appropriate beam pairs and measurement resources based on the specific distributed MIMO architecture, making the calibration process adaptable to various topologies and beamforming implementations.
Data Source
AI summary
A method of controlling over-the-air beamforming calibration for a multi-antenna transceiver system having a plurality of beamforming sub-systems connected to respective transceiver chains, wherein each beamforming sub-system is included in an access point of a distributed multiple-input multiple-output (MIMO) system, and wherein each beamforming sub-system is associated with a set of available beams. The method includes selecting pairs of one transmission beam and one reception beam, wherein a pair of the one transmission beam and the one reception beam are selected from the set of available beams of different ones of the beamforming sub-systems, and instructing the beamforming sub-systems to use each selected pair of one transmission beam and one reception beam for sounding signal measurements in a respective measurement resource.