RU Precoding Matrix Storage for Multi-Cell MIMO Fronthaul
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Solution Overview
Problem
The increasing demand for wireless communication bandwidth and the need to reduce installation costs of base stations in high-frequency communication systems necessitate an efficient distribution of digital and radio units, while maintaining effective signal processing capabilities.
Innovation Solution
A method and electronic device for a radio unit (RU) that identifies and stores precoding matrices and address information for multiple input multiple output (MIMO) layers across multiple cells, optimizing the distribution of processing functions between a digital unit (DU) and RU through a fronthaul interface, allowing for efficient signal processing and reduced installation costs.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If multiple MIMO layers are distributed across multiple cells in the RU, then signal transmission performance is improved and DU burden is reduced, but device complexity and memory requirements increase
Solution Approach 1:
The patent segments the MIMO processing functions by separating precoding matrix identification and storage between the RU and DU. The RU stores only the necessary precoding matrices for active cells in its memory, while the DU maintains the complete set of precoding matrices. This segmentation allows the RU to handle multiple cells efficiently without requiring excessive memory resources, thus improving signal transmission performance while controlling device complexity.
Solution Approach 2:
The patent introduces a new dimension of organization by implementing a hierarchical memory structure across two devices (RU and DU). Instead of concentrating all precoding matrices in one location, the system distributes them across different dimensional layers - the RU has a smaller local memory for immediate access, while the DU provides a larger remote memory repository. This dimensional distribution enables efficient multi-cell handling without overwhelming the RU's local resources.
2Reliability
If precoding matrices for multiple cells are stored in RU memory, then MIMO signal processing capability is enhanced, but installation costs and memory requirements increase
Solution Approach 1:
The patent extracts the bulk precoding matrix storage function from the RU and relocates it to the DU. The RU's memory is used only for storing the specific precoding matrices needed for currently active cells, while the DU stores the complete library of precoding matrices. This extraction reduces the RU's memory requirements and associated installation costs, while the MIMO signal processing capability is maintained through the DU's ability to provide precoding matrices on demand via the fronthaul interface.
Solution Approach 2:
The fronthaul interface acts as an intermediary between the RU and DU, enabling the RU to access precoding matrices stored in the DU when needed. This intermediary mechanism allows the system to maintain high MIMO processing capability without requiring the RU to have large local memory, thus reducing installation costs while preserving signal processing reliability.
3Productivity
If the RU handles processing for multiple cells, then throughput in the fronthaul is increased, but the complexity of managing MIMO layers increases
Solution Approach 1:
The patent applies preliminary action by having the DU pre-calculate and make available precoding matrices for multiple cells before they are needed at the RU. The RU receives and stores these precoding matrices in advance in its memory, so when multiple cells become active, the RU can immediately process them without complex real-time calculations. This preliminary preparation increases fronthaul throughput while reducing the operational complexity of MIMO layer management at the RU.
Data Source
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AI summary
A method performed by a radio unit (RU) may comprise the steps of: acquiring first cell information about a first cell and second cell information about a second cell; identifying at least one first multiple input multiple output (MIMO) layer for the first cell and at least one second MIMO layer for the second cell among MIMO layers associated with a memory; identifying first address information for the at least one first MIMO layer from a first precoding matrix for the first cell and a precoding matrix for the MIMO layers; identifying second address information for the at least second MIMO layer from a second precoding matrix for the second cell and the precoding matrix; and storing, on the memory, the precoding matrix identified on the basis of the first precoding matrix, the second precoding matrix, the first address information, and the second address information.