User Equipment Random Access Timing for TDD Downlink Conflicts

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Solution Overview

Problem

In wireless communications, particularly in TDD scenarios, the transmission occasion of a random access message conflicts with the time domain resource indicated by a network-side message, leading to potential interference with downlink signal transmission.

Innovation Solution

A method and apparatus for user equipment to handle such conflicts by transmitting, canceling, delaying, or ignoring the random access message, based on the specific conflict scenario, using techniques like discarding DCI, skipping downlink signals, and ensuring sufficient time gaps to avoid interference.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If the UE transmits the random access message on the configured transmission occasion, then the random access procedure can be completed, but interference is caused to downlink signal transmission of the network side due to conflict with TDD configuration information

Engineering Contradiction:
Improverandom access completionVSAvoidinterference to downlink signal
Core Design Contradiction:
ProductivityVSObject-affected harmful factors

Solution Approach 1:

The network side performs preliminary configuration by pre-defining a set of candidate time domain resources for random access messages and indicating which resources are available through network-side messages. The UE checks availability before transmission, preventing interference in advance by only transmitting on pre-approved resources that don't conflict with downlink configurations.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The system dynamically determines valid random access transmission occasions based on real-time TDD configuration information. The network side can update the set of available time domain resources through network-side messages, allowing the random access procedure to adapt to changing TDD configurations and avoid interference while maintaining flexibility.

Inventive Principle:
Principle #15Dynamics

2Object-affected harmful factors

If the UE cancels or delays transmission of the random access message to avoid conflict, then interference to downlink signal is avoided, but the random access procedure efficiency is reduced

Engineering Contradiction:
Improveinterference to downlink signalVSAvoidrandom access procedure delay
Core Design Contradiction:
Object-affected harmful factorsVSLoss of time

Solution Approach 1:

The network side pre-configures multiple candidate time domain resources and indicates available resources in advance through network-side messages. This allows the UE to identify valid transmission occasions before attempting random access, eliminating the need for cancellations or delays by providing a ready list of approved transmission times that are guaranteed to be interference-free.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The system changes the parameter of time domain resource selection from static to dynamic based on TDD configuration. By maintaining a set of candidate resources and updating availability indicators, the system allows the UE to select from multiple valid options, ensuring timely transmission without interference by adapting the available time slots to current network conditions.

Inventive Principle:
Principle #35Parameter changes

Data Source

PatentEP3965514B1Random access method and apparatus, and user equipment
Publication Date: 2025.08.27 VIVO MOBILE COMM CO LTD
  • EP3965514B1 patent drawingFigure 1~2
  • EP3965514B1 patent drawingFigure 3~5
  • EP3965514B1 patent drawingFigure 6

AI summary

This disclosure provides a random access method and apparatus, and user equipment, and belongs to the field of wireless communications technologies. The random access method is applied to user equipment and includes: in a case that a time domain resource for a random access message conflicts with a time domain resource indicated by a network-side message, performing any one of the following: transmitting the random access message on the time domain resource for the random access message; canceling transmission of the random access message; delaying transmission of the random access message; and ignoring the network-side message.