UE Connection Fallback Handling for Accurate Service Requests
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Solution Overview
Problem
The existing 3GPP TS 24.501 specification fails to accurately describe the setting of service type and uplink data status information elements in SERVICE REQUEST messages when a user equipment (UE) receives a fallback indication from lower layers, leading to incomplete and incorrect UE behavior in initiating service request or registration procedures.
Innovation Solution
The proposed solution supplements the existing cases in 3GPP TS 24.501 by defining new scenarios (i, j, k, and l) for UE behavior upon receiving a fallback indication, specifying how to set the service type and uplink data status information elements in SERVICE REQUEST and REGISTRATION REQUEST messages based on the UE's mode, pending procedures, and data availability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the existing 3GPP TS 24.501 specification is used without supplements, then the specification remains simple and easy to implement, but the UE behavior description becomes incomplete and incorrect for fallback indication scenarios
Solution Approach 1:
The patent applies preliminary action by defining UE behavior rules in advance for fallback indication scenarios before actual operation occurs. The specification supplements pre-establish the correct behavior patterns for setting service type and uplink data status information elements, so that UEs can reliably determine their actions without ambiguity when receiving fallback indications, thus improving reliability without requiring complex real-time decision mechanisms
Solution Approach 2:
The patent segments the UE behavior specification into distinct cases (cases i, j, k, l) based on different operational scenarios. Each case defines specific rules for setting information elements, breaking down the complex fallback indication handling into manageable, scenario-specific segments. This segmentation allows the specification to remain structured and implementable while comprehensively covering various operational conditions
2Loss of information
If new scenarios are defined to cover all fallback indication cases, then the completeness of UE behavior specification improves, but the difficulty of detecting and measuring correct behavior increases
Solution Approach 1:
The patent applies local quality by providing specific, tailored rules for each operational scenario rather than a single generic rule. Each case (i, j, k, l) has locally optimized behavior definitions that match its specific conditions, such as different service type settings or uplink data status configurations. This allows comprehensive coverage of all scenarios while maintaining clear, scenario-specific verification criteria that reduce overall measurement difficulty
Solution Approach 2:
The patent defines explicit rules for each case that may be more detailed than the minimum required, ensuring complete coverage of all fallback indication scenarios. By providing exhaustive case definitions with specific information element settings, the specification achieves complete information coverage while making verification straightforward through clear, prescriptive rules for each scenario
Data Source
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AI summary
An apparatus comprising at least one processor and at least one memory storing instructions. The instructions, when executed by the at least one processor, cause the apparatus to: in response to receiving a fallback indication from a radio resource control layer, when the apparatus has no pending non-access stratum procedure and pending uplink user data: invoke a service request procedure; set an uplink data status information element (IE) in a service request message to indicate one or more packet data unit (PDU) sessions for which user-plane resources were active prior to receiving the fallback indication; and set a service type IE in the service request message to "emergency services" if the uplink data status IE indicates an emergency PDU session, or to "data" if the uplink data status IE indicates no emergency PDU session.