Terminal Device RSD Filtering for PDU Session Adaptability
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Solution Overview
Problem
In wireless communication, when a terminal device receives a rejection message from a network device due to unsupported session parameters, it faces challenges in efficiently selecting alternative parameters to establish a PDU session, leading to increased signaling interaction and evaluation time.
Innovation Solution
The method involves a terminal device and a network device exchanging cause parameters to determine which route selection descriptors (RSDs) to ignore or skip, based on conditions such as unsupported service and session continuity modes, or differences in data network names and single-network slice selection assistant information, allowing the terminal device to adjust its parameter selection for successful PDU session establishment.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If the terminal device uses multiple RSDs to establish PDU sessions, then the adaptability of session establishment is improved, but the time required for parameter evaluation and selection increases
Solution Approach 1:
The terminal device pre-evaluates and sorts multiple RSDs before PDU session establishment, ranking them by priority and compatibility. This preliminary action allows the device to quickly select the most suitable RSD when session establishment is needed, avoiding time-consuming evaluation during the actual session setup process.
Solution Approach 2:
The terminal device divides the evaluation of RSDs into separate, independent steps: first evaluating SSC mode compatibility, then DNN availability, then S-NSSAI support. This segmentation allows the device to systematically filter RSDs through multiple criteria without overwhelming complexity, improving both adaptability and evaluation efficiency.
2Reliability
If the terminal device attempts to use unsupported session parameters, then the completeness of parameter testing is improved, but the signaling overhead increases
Solution Approach 1:
The terminal device performs preliminary compatibility verification of session parameters against network device capabilities before attempting PDU session establishment. By checking SSC mode support, DNN availability, and S-NSSAI compatibility in advance, the device avoids transmitting unsupported parameters, thereby reducing unnecessary signaling overhead while maintaining reliable parameter compatibility verification.
3Measurement precision
If the terminal device re-evaluates all RSDs after receiving rejection message, then the accuracy of parameter selection is improved, but the establishment time increases
Solution Approach 1:
After receiving a rejection message, the terminal device segments the RSD re-evaluation process by identifying only the specific parameter that caused rejection (e.g., SSC mode, DNN, or S-NSSAI) and adjusting only the affected RSDs accordingly. This selective re-evaluation maintains parameter selection accuracy while significantly reducing the time required compared to re-evaluating all RSDs from scratch.
Solution Approach 2:
The terminal device skips RSDs that are already known to be incompatible based on previous evaluation results and rejection messages. By utilizing the pre-established priority ordering and compatibility information, the device rapidly moves through the RSD list, skipping obviously unsuitable options and focusing evaluation only on potentially viable alternatives, thus reducing establishment time without sacrificing selection accuracy.
Data Source
AI summary
Methods for wireless communication, a terminal device, and a network device are provided. The method includes: receiving, by the terminal device, a first message transmitted by a network device, where the first message includes a cause parameter; and ignoring or skip using, by the terminal device, a route selection descriptor (RSD) unsatisfying a cause-parameter condition according to the cause parameter.