Beamforming Weight Signaling for DU-RU Fronthaul Throughput
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Solution Overview
Problem
The increasing demand for wireless communication capacity and the need to reduce installation costs of base stations in high-frequency communication systems necessitate a separation of base stations into distributed units (DUs) and radio units (RUs), requiring efficient communication protocols for the fronthaul interface to manage beamforming weights effectively.
Innovation Solution
The proposed solution involves transmitting format information for beamforming weights and control-plane messages between DUs and RUs, allowing the RUs to identify in-phase and quadrature values within defined ranges, thereby optimizing beamforming operations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If base stations are separated into distributed units and radio units to reduce installation costs, then device complexity is reduced, but communication throughput deteriorates due to fronthaul interface limitations
Solution Approach 1:
The patent applies parameter changes by dynamically adjusting beamforming weight parameters (in-phase and quadrature values) transmitted over the fronthaul interface. By optimizing these parameters, the system maintains high communication throughput despite the functional separation into DU and RU, resolving the throughput deterioration caused by the split architecture.
2Measurement precision
If beamforming weight precision is increased to improve communication performance, then measurement precision is improved, but loss of information increases due to higher bandwidth requirements
Solution Approach 1:
The patent implements partial action by transmitting only the necessary precision of beamforming weights (in-phase and quadrature values within specific ranges) rather than full-precision complex numbers. This approach maintains sufficient beamforming performance while reducing fronthaul bandwidth consumption, effectively balancing precision requirements with information loss constraints.
Solution Approach 2:
The system changes the parameter representation by using constrained in-phase and quadrature value ranges instead of full complex number precision. This parameter transformation reduces the information bits required for beamforming weight transmission while maintaining effective beamforming capability, thus reducing loss of information.
3Ease of manufacture
If function split between DU and RU is implemented to reduce installation costs, then ease of manufacture is improved, but device complexity increases due to interface protocol requirements
Solution Approach 1:
The patent applies segmentation by dividing the base station into independent DU and RU units with clearly defined functional boundaries. The DU handles higher-layer processing while the RU handles radio frequency functions, allowing independent manufacturing and deployment. This segmentation improves ease of manufacture while the standardized interface protocol manages the complexity of inter-unit communication.
Data Source
AI summary
A method performed by a distributed unit (DU) comprises: transmitting, to a radio unit (RU), format information for indicating a maximum value of an in-phase value of a beamforming weight and a quadrature value of the beamforming weight; identifying the in-phase value and the quadrature value on the basis of a range determined by the maximum value; and transmitting, to the RU, a control-plane (C-plane) message comprising at least one parameter indicative of the in-phase value and the quadrature value.