RRC Inactive Uplink Grants for Low-Latency UE Transmission

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Solution Overview

Problem

Existing wireless communication systems, such as 5G NR, require improvements for efficient uplink transmissions in the RRC_INACTIVE state without transitioning to the RRC_CONNECTED state, particularly in managing configured UL grants and UE capabilities for UL data transmission.

Innovation Solution

The system allows UE to perform UL transmissions in RRC_INACTIVE state by configuring and managing configured UL grants (CG) through suspend configurations, UE capability signaling, and network indications, enabling efficient resource allocation and data handling without state transitions.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If UE transitions to RRC_CONNECTED state for UL data transmission, then reliable data transmission is ensured, but state transition overhead and latency increase

Engineering Contradiction:

Improvedata transmission reliabilityVSAvoidstate transition latency

Core Design Contradiction:

ReliabilityVSLoss of time

Solution Approach 1:

The network pre-configures UL grants and associated parameters (TC-List, pathlossReferenceList, etc.) to the UE in RRC_INACTIVE state before data transmission is needed. This preliminary configuration enables the UE to immediately transmit data without transitioning to RRC_CONNECTED, thus reducing state transition latency while maintaining transmission reliability through pre-established resource allocations.

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The patent introduces an intermediate transmission state where UE can send data in RRC_INACTIVE using pre-configured grants. This intermediary mechanism bridges the gap between the resource constraints of RRC_INACTIVE and the transmission reliability of RRC_CONNECTED, allowing data transmission without full state transition while maintaining controlled reliability through network-pre-configured parameters.

Inventive Principle:

Principle #24Intermediary (Mediator)

2Loss of time

If UE uses pre-configured UL grants in RRC_INACTIVE state, then transmission latency is reduced, but resource allocation flexibility decreases

Engineering Contradiction:

Improvetransmission latencyVSAvoidresource allocation flexibility

Core Design Contradiction:

Loss of timeVSAdaptability or versatility

Solution Approach 1:

The patent enables dynamic switching between pre-configured grants and other transmission mechanisms. The UE can select from multiple TC-Lists and pathlossReferenceLists based on current channel conditions and data characteristics. This dynamic adaptability allows the system to maintain low latency through pre-configured grants while preserving flexibility by allowing UE to choose appropriate resources based on real-time conditions.

Inventive Principle:

Principle #15Dynamics

Solution Approach 2:

The network configures multiple parameter sets including different TC-Lists (timing advance values), pathlossReferenceLists (reference signals for pathloss calculation), and grant configurations. The UE can change these parameters based on channel conditions and data requirements, transforming static pre-configured grants into adaptable transmission resources that maintain both low latency and flexibility.

Inventive Principle:

Principle #35Parameter changes

3Adaptability or versatility

If network configures multiple TC-Lists and pathlossReferenceLists, then transmission adaptability improves, but configuration complexity increases

Engineering Contradiction:

Improvetransmission adaptabilityVSAvoidconfiguration complexity

Core Design Contradiction:

Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The patent segments the configuration into multiple independent lists: TC-Lists for different timing advance values, pathlossReferenceLists for different reference signals, and associated parameter sets. Each list contains multiple entries that can be independently selected based on channel conditions. This segmentation allows the UE to selectively use only the necessary subsets of configurations, reducing the effective complexity while maintaining comprehensive adaptability across different transmission scenarios.

Inventive Principle:

Principle #1Segmentation

Data Source

PatentEP4122250B1Wireless communication method and user equipment for performing transmission in RRC_inactive state

Publication Date: 2026.01.07 SHARP KK

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AI summary

A wireless communication method and a User Equipment (UE) for performing transmissions in a Radio Resource Control (RRC) _INACTIVE state are provided. The wireless communication method includes: receiving, in an RRC_CONNECTED state, an RRC release message including first information and second information, the first information associated with a Logical Channel (LCH) configuration, the second information including a plurality of Configured Grant (CG) configurations; transitioning from the RRC_CONNECTED state to the RRC_INACTIVE state; determining that data from an LCH corresponding to the LCH configuration become available for UL transmission; determining whether to transmit the data in the RRC_INACTIVE state according to whether any of the plurality of CG configurations is associated with the LCH configuration; and in a case that at least one of the plurality of CG configurations is associated with the LCH configuration, transmitting the data through a set of Physical Uplink Shared Channels (PUSCHs).