RRC Reestablishment PDCP Type Configuration for Dual-Core Networks
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Solution Overview
Problem
The 3GPP radio access network lacks clear specifications for Packet Data Convergence Protocol (PDCP) type selection and switching during RRC reestablishment in eLTE, particularly for SRB1 and SRB2 bearers, and determines how a network side identifies an ECGI when a cell supports both 4G and 5G core networks during RRC reestablishment.
Innovation Solution
A method for determining the PDCP type supported by a target network during RRC reestablishment, where the terminal configures SRB1 and SRB2 bearers using either type-1 or type-2 PDCP based on network capabilities, and reconfigures bearers accordingly to ensure successful RRC reestablishment, including switching between LTE and NR PDCP as needed.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Extent of automation
If the terminal uses default PDCP type switching during RRC reestablishment, then the reestablishment process can proceed automatically, but the PDCP type selection and bearer configuration becomes unclear and unreliable
Solution Approach 1:
The terminal determines and stores the target network type (4G or 5G) before RRC reestablishment occurs. When reestablishment is triggered, the terminal already has the predetermined PDCP type information ready, eliminating the uncertainty of automatic switching while maintaining the automated reestablishment process. This preliminary determination ensures reliable PDCP type selection without manual intervention.
2Adaptability or versatility
If the network supports both 4G and 5G core networks simultaneously, then the network flexibility and adaptability increases, but the method for determining ECGI during reestablishment becomes undefined
Solution Approach 1:
The target network type (determined through preliminary action) serves as an intermediary that resolves the ambiguity of ECGI determination. When the terminal needs to report ECGI during reestablishment, it uses the predetermined target network type to select the appropriate ECGI from the cell's dual core network support, making the ECGI determination process clear and reliable rather than undefined.
3Reliability
If the terminal configures SRB1 and SRB2 bearers during reestablishment, then the communication functionality is restored, but the PDCP type configuration becomes unspecified and error-prone
Solution Approach 1:
The terminal determines the target network type and corresponding PDCP type before the bearer configuration step during RRC reestablishment. This preliminary determination simplifies the bearer configuration process by providing clear guidance on which PDCP type to use for SRB1 and SRB2, eliminating the specification gaps and reducing configuration errors while ensuring communication functionality is reliably restored.
Data Source
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AI summary
This disclosure provides a bearer configuration method for RRC connection reestablishment, a terminal, and a network device. The method in this disclosure includes: when receiving an RRC reestablishment complete message sent by a terminal, determining a Packet Data Convergence Protocol PDCP type supported by a target network to be accessed by the terminal, where the PDCP type includes type-1 PDCP supporting a first network or type-2 PDCP supporting a second network; and reconfiguring bearers in a subsequent RRC process based on the determined PDCP type.