OAM-Enhanced MIMO Precoding for Line-of-Sight Spectral Efficiency
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Solution Overview
Problem
In 5G networks, conventional MIMO technology is limited in channel environments with a large line of sight, as it degrades to SISO, restricting spectral efficiency and signal transmission capabilities.
Innovation Solution
A method to determine a precoding matrix that integrates OAM modes into the MIMO communication process, using CSI to identify line of sight conditions and adjust antenna port groups and OAM mode groups, enhancing spectral efficiency and performance by using OAM in MIMO.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If conventional MIMO technology is used in line of sight channel environments, then the system structure is simple and easy to implement, but the channel degrades to SISO and spectral efficiency is limited
Solution Approach 1:
The patent segments the channel environment into different types (line of sight vs. non-line of sight) and applies different precoding strategies for each. In line of sight environments, OAM modes are activated to enable multi-stream transmission, while conventional MIMO is used in other environments, thus improving spectral efficiency without unnecessarily complicating the system in all scenarios.
Solution Approach 2:
The patent dynamically selects between conventional MIMO and OAM-based precoding based on channel conditions. The receive end determines whether a line of sight exists and accordingly selects the appropriate precoding matrix type, enabling the system to adapt to changing environmental conditions and optimize spectral efficiency dynamically.
2Productivity
If OAM modes are integrated into MIMO communication, then spectral efficiency is improved and multi-stream transmission is enabled, but the precoding matrix complexity increases
Solution Approach 1:
The patent applies different precoding matrix structures to different spatial channels. The first precoding matrix (conventional MIMO) is applied to antenna ports not associated with OAM modes, while the second precoding matrix (OAM-based) is applied to antenna ports associated with OAM modes. This local differentiation enables multi-stream transmission where needed while keeping the overall system manageable.
Solution Approach 2:
The patent creates a universal precoding framework that can handle both conventional MIMO and OAM-based transmission through a unified second precoding matrix structure. This matrix simultaneously supports spatial multiplexing and OAM mode multiplexing, allowing the system to function in both line of sight and non-line of sight environments with a single versatile mechanism.
3Productivity
If OAM modes are used for signal transmission, then space division multiplexing capability is improved, but interference management becomes more complex
Solution Approach 1:
The patent introduces OAM modes as an additional dimension for signal differentiation beyond traditional spatial dimensions. By utilizing the orbital angular momentum dimension, the system can multiplex multiple data streams on the same spatial path without conventional spatial interference, thus improving space division multiplexing capability while managing interference through a new degree of freedom.
Data Source
AI summary
The present disclosure relates to precoding matrix determining methods, devices, and systems. In one example method, a receive end device obtains channel state information (CSI) of a first channel and information about P antenna port groups of a transmit end device. The receive end device determines V orbital angular momentum (OAM) mode groups based on the CSI of the first channel and first OAM modes, determines a first precoding matrix based on the P antenna port groups of the transmit end device and the V OAM mode groups, and sends, to the transmit end device, first indication information indicating the first precoding matrix. The transmit end device receives the first indication information, and determines the first precoding matrix based on the first indication information.