UE RNA Update Timer Logic for RRCReject Handling

Resolve Bottlenecks,
Find Innovative SolutionsGenerate Solutions

Solution Overview

Problem

Current specifications for UE operation in RRC_INACTIVE state in 5G NR networks are unclear regarding UE actions upon receiving an RRCReject message during periodic RNA updates, leading to potential anomalous behavior, increased power consumption, and unnecessary signaling.

Innovation Solution

Implement a method where the UE restarts the periodic RNA update timer (T380) and starts a wait timer (T302) upon receiving an RRCReject, with specific conditions for transmitting further RRCResumeRequest messages based on timer values and event triggers, and the network manages UE context storage.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If the UE continuously transmits RRCResumeRequest messages during periodic RNA updates upon receiving RRCReject, then the RNA update function is maintained, but unnecessary signaling and power consumption increase

Engineering Contradiction:

ImproveRNA update functionVSAvoidpower consumption

Core Design Contradiction:

ReliabilityVSUse of energy by moving object

Solution Approach 1:

The patent dynamically adjusts UE behavior based on the relationship between timer T380 (periodic RNA update timer) and timer T302 (wait timer from RRCReject). When T380 <= T302, the UE stops transmitting RRCResumeRequest messages until T302 expires, reducing power consumption. When T380 > T302, the UE transmits messages according to the T380 periodicity, maintaining RNA update function. This dynamic adaptation resolves the contradiction between maintaining reliability and reducing energy consumption.

Inventive Principle:

Principle #15Dynamics

Solution Approach 2:

The patent changes the operational parameters of the UE based on timer values. By comparing T380 and T302, the system adjusts whether the UE should transmit RRCResumeRequest messages or remain silent, effectively changing the transmission parameter from continuous to conditional based on timer relationships, thus reducing unnecessary signaling and power consumption while maintaining required functionality.

Inventive Principle:

Principle #35Parameter changes

2Reliability

If the UE continuously transmits RRCResumeRequest messages during periodic RNA updates upon receiving RRCReject, then the RNA update function is maintained, but signaling overhead increases

Engineering Contradiction:

ImproveRNA update functionVSAvoidsignaling overhead

Core Design Contradiction:

ReliabilityVSQuantity of substance

Solution Approach 1:

The patent implements dynamic control of RRCResumeRequest message transmission based on the comparison between timer T380 and timer T302. When T380 <= T302, transmission is suspended, reducing signaling overhead. When T380 > T302, transmission resumes according to periodic requirements, maintaining RNA update reliability. This dynamic approach eliminates unnecessary signaling while preserving essential update functions.

Inventive Principle:

Principle #15Dynamics

Solution Approach 2:

The system changes the transmission parameter of RRCResumeRequest messages based on timer relationships. By adjusting whether messages are transmitted or suppressed according to the T380 versus T302 comparison, the patent reduces signaling overhead by preventing redundant transmissions while ensuring necessary RNA updates occur.

Inventive Principle:

Principle #35Parameter changes

3Adaptability or versatility

If the UE behavior is not clearly defined upon receiving RRCReject during periodic RNA updates, then network flexibility is maintained, but anomalous UE behavior occurs

Engineering Contradiction:

Improvenetwork flexibilityVSAvoidUE behavior consistency

Core Design Contradiction:

Adaptability or versatilityVSReliability

Solution Approach 1:

The patent establishes preliminary rules for UE behavior upon receiving RRCReject during periodic RNA updates. By pre-defining the action based on the comparison between T380 and T302 timers, the patent eliminates ambiguity and ensures consistent UE behavior across different scenarios, while the network retains flexibility to choose appropriate reject strategies.

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The patent implements a feedback mechanism where UE behavior is determined by comparing timer values T380 and T302. This feedback loop ensures that UEs consistently follow the same decision logic based on their timer states, eliminating anomalous behavior while allowing the network to maintain flexibility in its reject messaging strategy.

Inventive Principle:

Principle #23Feedback

Data Source

PatentEP4669020A2Methods for handling periodic radio access network notification area (RNA) update configuration upon reject

Publication Date: 2025.12.24 TELEFONAKTIEBOLAGET LM ERICSSON (PUBL)

Figure 1
Figure 2A~2C
Figure 3A

AI summary

According to an aspect, a user equipment, UE, in a suspended state in a Radio Access Network, RAN, in response to expiration of a first timer, transmits (1910) an RRCResumeRequest message. The UE receives (1920) a reject message in response to the RRCResumeRequest message. In response to the reject message, the UE starts (1930) a second timer and subsequently transmits (1940) a further RRCResumeRequest message. The further RRCResumeRequest message is received by the network during a period bounded approximately by the lesser of a duration of the second timer and a period of the periodic UE event and the greater of the duration of the second timer and the period of the periodic UE event.