2-Step Random Access Msg A Transmission Method

Solution Overview

Problem

In 5G and New Radio (NR) systems, the 2-step random access procedure faces challenges in efficiently transmitting the first message (Msg A) due to the flexible slot format indicating manner, which can lead to resource conflicts and restricted transmission of PRACH and PUSCH.

Innovation Solution

A random access method where a terminal device determines, based on a predetermined rule, whether to transmit an uplink channel in the 2-step random access procedure. If not transmitting PRACH, both PRACH and PUSCH are not transmitted. If not transmitting PUSCH, only the decision on PRACH transmission is made.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If the flexible slot format indicating manner is used in 2-step random access procedure, then the adaptability of slot format is improved, but resource conflicts occur between PRACH and PUSCH transmission

Engineering Contradiction:

Improveslot format adaptabilityVSAvoidresource conflicts

Core Design Contradiction:

Adaptability or versatilityVSObject-affected harmful factors

Solution Approach 1:

The patent applies local quality by determining different transmission decisions for different channels (PRACH vs PUSCH) based on their specific characteristics and requirements. The terminal device independently evaluates whether to transmit PRACH and PUSCH separately, allowing each channel to have its own transmission quality and properties rather than treating them uniformly.

Inventive Principle:

Principle #3Local quality

Solution Approach 2:

The patent implements dynamics by making the transmission decision adaptive and changeable based on real-time slot format conditions. The terminal device dynamically determines whether to transmit PRACH, PUSCH, both, or neither based on the detected slot format and predetermined rules, rather than using a fixed transmission strategy.

Inventive Principle:

Principle #15Dynamics

2Adaptability or versatility

If the flexible slot format indicating manner is used in 2-step random access procedure, then the slot format flexibility is improved, but the transmission reliability of Msg A is reduced

Engineering Contradiction:

Improveslot format flexibilityVSAvoidMsg A transmission reliability

Core Design Contradiction:

Adaptability or versatilityVSReliability

Solution Approach 1:

The patent applies parameter changes by modifying the transmission parameters (whether to transmit PRACH and/or PUSCH) based on the slot format parameters. The terminal device changes its transmission behavior according to the detected slot format conditions, adjusting the transmission parameters to maintain reliability while adapting to flexible slot formats.

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The patent implements dynamics by making the transmission decision adaptive and changeable based on real-time slot format conditions. The terminal device dynamically determines whether to transmit PRACH, PUSCH, both, or neither based on the detected slot format and predetermined rules, rather than using a fixed transmission strategy.

Inventive Principle:

Principle #15Dynamics

3Loss of information

If the terminal device transmits both PRACH and PUSCH in Msg A, then the information transmission completeness is improved, but the resource consumption increases

Engineering Contradiction:

Improveinformation transmission completenessVSAvoidtransmission energy consumption

Core Design Contradiction:

Loss of informationVSUse of energy by moving object

Solution Approach 1:

The patent applies partial action by allowing the terminal device to transmit only the necessary portion of Msg A (either PRACH alone, PUSCH alone, or both) based on the slot format conditions and information requirements. This avoids the excessive action of always transmitting both channels, reducing energy consumption while maintaining information completeness when needed.

Inventive Principle:

Principle #16Partial or excessive action

Solution Approach 2:

The patent applies parameter changes by modifying the transmission parameters (whether to transmit PRACH and/or PUSCH) based on the slot format parameters. The terminal device changes its transmission behavior according to the detected slot format conditions, adjusting the transmission parameters to maintain reliability while adapting to flexible slot formats.

Inventive Principle:

Principle #35Parameter changes

Data Source

PatentUS12232185B2Random access method and terminal device

Publication Date: 2025.02.18 GUANGDONG OPPO MOBILE TELECOMMUNICATIONS CORP LTD

AI summary

Provided are a method for determining random access and a terminal device, which enable effective transmission of Msg A in a 2-step random access procedure. The method includes: determining, by a terminal device based on a predetermined rule, whether to send an uplink channel on a transmission occasion corresponding to the uplink channel in a first message of a 2-step random access procedure, where the uplink channel includes a physical random access channel PRACH and a physical uplink shared channel PUSCH; not sending the PRACH and not sending the PUSCH by the terminal device in a case that the terminal device determines not to send the PRACH; and not sending the PUSCH by the terminal device and sending or not sending the PRACH by the terminal device in a case that the terminal device determines not to send the PUSCH.