PRACH Transmission Timing Indication for Coverage-Limited Random Access

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Solution Overview

Problem

The existing PRACH format designs in 5G NR systems face challenges with limited coverage due to cyclic prefix lengths that are less than a threshold, leading to difficulties in determining the correct timing advance and potential failures in random access procedures.

Innovation Solution

Implementing enhancements to PRACH procedures by configuring mappings between RTD or TA command values and PRACH groups, allowing wireless communication devices to switch transmission resources and utilize multiple TA commands for determining transmission timing, thereby improving coverage and reducing random access procedure failures.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Device complexity

If cyclic prefix length is kept short to maintain PRACH format design, then system complexity is reduced, but coverage is limited and timing advance determination fails

Engineering Contradiction:

ImprovePRACH format design complexityVSAvoidrandom access procedure reliability

Core Design Contradiction:

Device complexityVSReliability

Solution Approach 1:

The patent segments the PRACH procedure into multiple groups (first group and second group) with different transmission resources. When random access fails in the first group, the device switches to the second group, dividing the problem into manageable parts that can be handled differently based on failure conditions

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The patent changes transmission parameters by switching between different PRACH resource groups. The second group uses different transmission resources than the first group, allowing parameter adjustment to overcome coverage limitations and timing advance determination failures

Inventive Principle:

Principle #35Parameter changes

2Ease of operation

If transmission resources are fixed in a single group, then device operation is simplified, but coverage extension and failure recovery are limited

Engineering Contradiction:

Improvedevice operation simplicityVSAvoidcoverage and failure recovery

Core Design Contradiction:

Ease of operationVSReliability

Solution Approach 1:

The patent makes the PRACH system multi-functional by configuring two groups of transmission resources with different characteristics. The system can universally handle both normal random access (first group) and failure recovery scenarios (second group), making it adaptable to different operational conditions without requiring separate systems

Inventive Principle:

Principle #6Universality (Multi-functionality)

3Speed

If timing advance is determined using a single TA command, then procedure speed is maintained, but accuracy fails under varying round trip delays

Engineering Contradiction:

Improverandom access procedure speedVSAvoidtiming advance accuracy

Core Design Contradiction:

SpeedVSMeasurement precision

Solution Approach 1:

The patent introduces dynamics into the TA command determination by allowing switching between different TA commands based on which PRACH resource group succeeds. The system adapts its TA command selection dynamically rather than using a fixed single TA command, enabling accurate timing advance determination under varying round trip delay conditions

Inventive Principle:

Principle #15Dynamics

Data Source

PatentUS20250274988A1Systems and methods for transmission timing indication

Publication Date: 2025.08.28 ZTE CORP

AI summary

The present arrangement relates to systems, methods, and non-transitory computer-readable media for transmission timing indication. The method may include receiving, from a network, two or more groups of transmission resources for a random access procedure; determining that a first random access procedure performed using a first transmission resource in a first group of resources has failed; and performing a second random access procedure using a second transmission resource in a second group of transmission resources.