SUL Load Balancing in 5G CU-DU Architecture
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Solution Overview
Problem
In the context of 5G NR, the supplementary uplink (SUL) load balancing between gNB-CU and gNB-DU in a CU-DU architecture is challenging due to the inability of the gNB-CU to accurately identify and manage SUL congestion across cells, leading to performance degradation at the cell edge.
Innovation Solution
The method involves the gNB-DU monitoring and reporting SUL load status to the gNB-CU, which then adjusts parameters such as q-RxLevMinSUL to balance the load, potentially initiating handovers to neighboring cells with lower SUL load, thereby distributing the load effectively.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If gNB-CU does not monitor SUL load status directly, then device complexity is reduced, but measurement precision of SUL congestion status deteriorates
Solution Approach 1:
The gNB-DU acts as an intermediary that monitors SUL load status and reports to gNB-CU. The gNB-DU collects raw load information from multiple cells and processes it before reporting to gNB-CU, enabling the gNB-CU to make informed decisions without directly handling complex monitoring operations.
Solution Approach 2:
The monitoring and measurement functions are extracted from gNB-CU and delegated to gNB-DU. The gNB-DU extracts SUL load status information from multiple cells, processes it locally, and reports only the necessary aggregated information to gNB-CU, reducing the complexity burden on gNB-CU.
2Device complexity
If SUL load balancing is not implemented, then device complexity is reduced, but service quality deteriorates due to cell edge performance degradation
Solution Approach 1:
The system implements dynamic SUL load balancing where parameters such as q-RxLevMinSUL are adjusted based on real-time load conditions. The gNB-CU can dynamically change these parameters to redistribute SUL traffic from congested cells to less loaded cells, maintaining cell edge performance adaptively.
Solution Approach 2:
The invention changes SUL-related parameters (e.g., q-RxLevMinSUL) to achieve load balancing. By adjusting these parameters based on reported load status, the system can shift traffic patterns and improve cell edge performance without requiring complex architectural changes.
3Manufacturing precision
If manual SUL parameter adjustment is used, then manufacturing precision is improved, but productivity decreases due to slow response to congestion changes
Solution Approach 1:
The system establishes a feedback loop where gNB-DU continuously monitors SUL load status and reports to gNB-CU. Based on this feedback, gNB-CU adjusts SUL parameters dynamically. This closed-loop control enables both precise parameter adjustment and rapid response to congestion changes.
Solution Approach 2:
The gNB-CU can proactively adjust SUL parameters based on predicted or early-warning load status information. By taking preliminary actions before severe congestion occurs, the system maintains precise control while responding quickly to potential issues.
Data Source
AI summary
A method and apparatus for support of load balancing for supplementary uplink (SUL) in central unit (CU)-distributed unit (DU) architecture in a new radio access technology (NR) is provided. A gNB central unit (gNB-CU) receives, from at least one gNB distributed unit (gNB-DU), information related to a load status of supplementary uplink (SUL) for the at least one gNB-DU, and determines to adjust at least one parameter related to the SUL for a gNB-DU, among the at least one gNB-DU, based on the information related to the load status of the SUL for the gNB-DU. Upon receiving information related to the at least one parameter related to the SUL from the gNB-CU, the gNB-DU may adjust the at least one parameter related to the SUL based on the information related to the at least one parameter related to the SUL.