Bearer Continuity via Parameter Mapping in 3GPP Inter-RAT Changes
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Solution Overview
Problem
Inter-RAT bearer changes in 3GPP networks face issues due to mismatches in mandatory parameters between different radio access technologies, leading to problems in setting up new PDP contexts and potential termination of bearer changes.
Innovation Solution
The implementation of a bearer preservation procedure that detects missing mandatory parameters during inter-RAT changes, using predefined or dynamically obtained parameter settings, and signaling procedures to maintain bearer continuity, including preconfigured values, network provisioning, and hybrid solutions to ensure seamless transitions between 4G, 3G, and 2G systems.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If inter-RAT bearer change is performed with optional parameters omitted in EPS bearer, then device complexity and signaling overhead are reduced, but reliability deteriorates because mandatory parameters are missing for PDP context setup
Solution Approach 1:
The network performs preliminary actions by storing and provisioning the missing mandatory parameters (LLC SAPI, radio priority, QoS parameters) in the HSS/AAA server before the bearer change occurs. When inter-RAT bearer change is detected, these parameters are automatically retrieved and provided to ensure successful PDP context setup without requiring complex real-time negotiation
Solution Approach 2:
The HSS/AAA server acts as an intermediary that bridges the EPS bearer context and the PDP context. It stores the mapping between EPS bearer identifiers and the corresponding mandatory parameters, and automatically provides these parameters during inter-RAT bearer change to ensure compatibility between different radio access technologies
2Reliability
If all mandatory parameters are included in EPS bearer, then reliability of PDP context setup is improved, but device complexity and signaling overhead increase
Solution Approach 1:
Different parts of the network are assigned different responsibilities: the UE and eNodeB handle optional parameters locally, while the HSS/AAA server is responsible for storing and managing the mandatory parameters. This local quality division allows the bearer setup to be simplified at the radio access side while ensuring reliability through centralized parameter management
Solution Approach 2:
The network infrastructure (HSS/AAA server) automatically provides the mandatory parameters during inter-RAT bearer change without requiring manual configuration or complex negotiation procedures. The system serves itself by having the server automatically retrieve and provide the necessary parameters based on the bearer change detection
3Ease of operation
If inter-RAT bearer change procedure is simplified with fewer parameters, then ease of operation is improved, but manufacturing precision of bearer parameters deteriorates
Solution Approach 1:
The mandatory parameters are preliminarily configured and stored in the HSS/AAA server during network provisioning, ensuring parameter configuration accuracy is maintained in advance. This preliminary action allows the actual bearer change procedure to be simplified without compromising parameter precision
Data Source
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AI summary
Methods and apparatus are provided for enhanced bearer continuity for the 3GPP network. In one novel aspect, the UE detects missing parameters for the inter-RAT bearer change in an idle state. The UE performs bearer preservation procedures to maintain the bearer continuity. In one embodiment, predefined /preconfigured parameter settings are used. In one embodiment, a mapping rule is used to map the missing parameter to a predefined value based on one or more known parameters. In another embodiment, the missing parameters are obtained from the network. In another embodiment, signaling procedures used to obtain the missing parameters. The signaling procedures include a service request, a UE-initiated bearer modification procedure. In one embodiment, the cell reselection is suspended such that the signaling procedure is performed to obtain the missing parameters before the cell reselection. In another embodiment, a RAU procedure is used upon detecting the missing of parameters.