Beamforming Weight Segmentation for Fronthaul Capacity Reduction
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
In distributed base station systems, the current functional split between the Base Band Unit (BBU) and Remote Radio Unit (RRU) leads to high fronthaul link capacity requirements and increased complexity for the RRU, especially when using massive MIMO, which is not compliant with O-RAN architecture and increases costs.
Innovation Solution
Decomposing beamforming weights into two parts, where the BBU determines and compresses the second part, and both parts are used for beamforming, with the first part for interference mitigation and the second part for expanding user-layer signals to antenna signals, reducing the complexity and fronthaul capacity requirements.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the current PHY-RF split between BBU and RRU is used with massive MIMO, then the wireless communication capacity is improved, but the fronthaul link capacity requirements increase dramatically and RRU complexity increases
Solution Approach 1:
The patent segments the beamforming weights into two distinct parts: first part beamforming weights and second part beamforming weights. This segmentation allows each part to handle specific functions (interference mitigation and spatial multiplexing respectively), reducing the overall complexity burden on the RRU while maintaining massive MIMO capacity.
Solution Approach 2:
The patent extracts the second part beamforming weights determination from the RRU and performs it in the BBU instead. This extraction reduces the computational complexity and processing burden on the RRU, while the BBU leverages its stronger processing capabilities to handle this function.
2Productivity
If the current PHY-RF split between BBU and RRU is used with massive MIMO, then the wireless communication capacity is improved, but the fronthaul link capacity requirements increase dramatically
Solution Approach 1:
The patent segments the beamforming weights into two parts transmitted separately over the fronthaul link. The first part beamforming weights are transmitted with higher precision while the second part can use lower precision, optimizing the fronthaul capacity utilization and reducing the total quantity of data that needs to be transmitted.
Solution Approach 2:
The patent changes the precision parameter for transmitting different parts of beamforming weights over the fronthaul link. By applying different precision levels to different parts (first part vs second part), the system optimizes fronthaul capacity requirements while maintaining overall system performance.
3Measurement precision
If beamforming weights are transmitted with high precision over fronthaul link, then the signal accuracy is improved, but the fronthaul capacity requirements increase
Solution Approach 1:
The patent segments beamforming weights into first part and second part, allowing different precision treatments for each segment. This enables the system to maintain signal accuracy where critical (first part) while reducing fronthaul capacity consumption (second part with lower precision).
Solution Approach 2:
The patent applies different precision parameters to different parts of the beamforming weights. The first part beamforming weights are transmitted with higher precision to maintain signal accuracy, while the second part uses lower precision, thereby optimizing the trade-off between signal accuracy and fronthaul capacity.
Data Source
AI summary
Disclosed is a method performed by a BBU system of a wireless communication network, comprising a distributed base station system (100), which comprises a BBU (110) and an RRU (120) connected over a fronthaul link (140). The method comprises determining first and second parts of beamforming weights based on a determined downlink channel estimate, and compressing the second part of the beamforming weights. The first part of the beamforming weights is determined for performing interference cancellation between user-layer signals, and the second part is determined for expanding the user-layer signals to antenna signals. The BBU then sends the first part and the compressed second part of the beamforming weights to the RRU, as well as the user-layer signals, over the fronthaul link (140). The RRU (120) then beamforms the user-layer signals according to the first and the second parts of the beamforming weights before sending the signals to a number of UEs (131, 132, 133).