Random Access Selection for Small Data in RRC Inactive State

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Solution Overview

Problem

In the NR system, data transmission from an RRC_INACTIVE state to an RRC_CONNECTED state is delayed due to the conversion process via a random access procedure.

Innovation Solution

A data transmission method that allows small data to be sent via a two-step or four-step random access procedure based on data volume, enabling timely transmission without waiting for state conversion, by determining the appropriate random access procedure for the terminal in the RRC_INACTIVE state.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If the terminal converts from RRC_INACTIVE state to RRC_CONNECTED state via random access procedure before data transmission, then the terminal can establish proper connection for data transmission, but the data transmission experiences large delay

Engineering Contradiction:

Improveconnection establishmentVSAvoiddata transmission delay

Core Design Contradiction:

ReliabilityVSLoss of time

Solution Approach 1:

The terminal performs random access procedure and transitions to RRC_CONNECTED state in advance before actual data transmission is needed. This preliminary state conversion ensures that the connection is already established when small data needs to be transmitted, eliminating the delay that would otherwise occur during the state conversion process.

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The patent dynamically adjusts the RRC state of the terminal based on data transmission requirements. The terminal can switch between RRC_INACTIVE and RRC_CONNECTED states flexibly, maintaining an active connection when small data transmission is anticipated, thereby balancing connection reliability with transmission speed.

Inventive Principle:

Principle #15Dynamics

2Loss of time

If the terminal maintains RRC_CONNECTED state for immediate data transmission, then data transmission delay is reduced, but system resources are consumed continuously

Engineering Contradiction:

Improvedata transmission delayVSAvoidsystem resource consumption

Core Design Contradiction:

Loss of timeVSUse of energy by moving object

Solution Approach 1:

Instead of maintaining full RRC_CONNECTED state continuously, the terminal adopts a partial connection approach by using RRC_INACTIVE state with dormant configuration. This allows the terminal to perform light random access procedures and transmit small amounts of data without fully activating the connection, thereby reducing system resource consumption while still enabling timely data transmission when needed.

Inventive Principle:

Principle #16Partial or excessive action

Solution Approach 2:

The patent changes the operational parameters of the terminal by introducing dormant downlink and uplink configurations. These parameter changes allow the terminal to operate in a low-power intermediate state (RRC_INACTIVE) rather than continuously maintaining full connection parameters, thus reducing energy consumption while preserving the ability to transmit data quickly when required.

Inventive Principle:

Principle #35Parameter changes

Data Source

PatentUS12507311B2Data transmission method and apparatus, terminal, network device and medium

Publication Date: 2025.12.23 BEIJING XIAOMI MOBILE SOFTWARE CO LTD

AI summary

Data transmission methods, a terminal, a network device and a non-transitory computer-readable storage medium thereof are provided. In a data transmission method, the terminal in a radio resource control (RRC) inactive state sends small data via a random access procedure, where the random access procedure is one of a two-step random access procedure or a four-step random access procedure, and the random access procedure is determined based on data volume of the small data.