CU-DU QoS Mapping in 5G SDAP Layer
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Solution Overview
Problem
In 5G communication systems, there is a need to effectively schedule bearers based on Quality of Service (QoS) parameters to ensure consistent and efficient data flow management between the Central Unit (CU) and Distributed Unit (DU), as existing methods lack a clear mechanism for mapping QoS data flows to bearers, leading to inefficiencies in resource allocation and data transmission.
Innovation Solution
The proposed solution involves the CU determining QoS parameters and mapping information between QoS data flows and bearers at the Service Data Adaptation Protocol (SDAP) layer, and then sending this information to the DU, allowing for flexible scheduling of bearers based on QoS parameters, load, and mapping information, which can be used for both initial setup and modification of bearers.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the CU determines QoS parameters and mapping information at the SDAP layer, then QoS consistency between CU and DU is improved, but the device complexity increases due to additional mapping determination and parameter calculation functions
Solution Approach 1:
The base station is segmented into CU and DU with clear functional boundaries. The CU handles high-level QoS parameter determination and mapping decisions at the SDAP layer, while the DU executes the actual scheduling based on received parameters. This segmentation allows the CU to maintain QoS consistency without overwhelming complexity, as the DU handles the computationally intensive scheduling operations.
Solution Approach 2:
The CU performs preliminary determination of QoS parameters and mapping information between QoS data flows and bearers before transmitting them to the DU. By pre-calculating and pre-configuring the mapping relationships and QoS parameters, the CU ensures consistency is established in advance, reducing the need for complex real-time negotiations and maintaining reliability while managing complexity through advance preparation.
2Productivity
If the DU schedules bearers based on QoS parameters and mapping information, then resource allocation efficiency is improved, but the loss of information increases due to the separation of QoS determination and scheduling functions
Solution Approach 1:
The system implements feedback mechanisms where the DU reports scheduling status and resource allocation results back to the CU. The CU uses this feedback to verify that QoS parameters are being applied correctly and to adjust mapping information as needed. This feedback loop prevents information loss by continuously validating that the QoS intentions from the CU are being properly executed at the DU.
Solution Approach 2:
The CU provides comprehensive mapping information between QoS data flows and bearers in advance to the DU, ensuring that all necessary QoS context is transmitted before scheduling begins. This preliminary transmission of complete mapping relationships prevents information loss during the separation of QoS determination and scheduling functions, as the DU receives all needed information upfront to make informed scheduling decisions.
3Device complexity
If multiple QoS data flows are mapped to a single bearer, then the device complexity is reduced, but the manufacturing precision deteriorates due to potential QoS parameter conflicts
Solution Approach 1:
The CU applies local quality by determining specific QoS parameters for each individual bearer based on the characteristics of the QoS data flows being mapped to it. When multiple data flows are mapped to a single bearer, the CU carefully selects and configures QoS parameters that are appropriate for that specific bearer's role and the aggregated traffic characteristics, ensuring that each bearer is optimized for its specific function rather than applying uniform parameters everywhere.
Solution Approach 2:
The system dynamically adjusts QoS parameters based on the specific mapping configuration. When multiple QoS data flows are mapped to a single bearer, the CU modifies the QoS parameters of that bearer to reflect the aggregated requirements of the mapped flows. This parameter adaptation ensures that even though multiple flows share a bearer, the QoS consistency is maintained by changing the bearer's parameters to match the combined traffic characteristics.
Data Source
AI summary
This application provides a communication method and a communication system. A central unit (CU) obtains a quality of service (QoS) parameter of a QoS data flow and performs mapping the QoS data flow to a bearer based on the QoS parameter of the QoS data flow. The CU determines a QoS parameter of the bearer based on the QoS parameter of the QoS data flow and sends a context setup request message to a distributed unit (DU), wherein the context setup request message comprises the QoS parameter of the bearer, the QoS parameter of the QoS data flow and the mapping relationship between the QoS data flow and the bearer.