Communication Node PRACH Allocation for Coverage Control

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Solution Overview

Problem

Existing wireless communication systems face challenges in enhancing the coverage of the Physical Random Access Channel (PRACH), which is critical for initial access and beam failure recovery, with unnecessary repetitions leading to increased random access collisions.

Innovation Solution

A method and apparatus that determine the number of time-frequency resources for PRACH transmissions based on events, information blocks, measurement results, and BWP configurations to optimize PRACH repetitions, reducing unnecessary repetitions and collisions.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If PRACH repetitions are performed to enhance uplink coverage, then coverage is improved, but random access collisions increase

Engineering Contradiction:
Improveuplink coverageVSAvoidrandom access collisions
Core Design Contradiction:
ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The patent implements dynamic selection of PRACH repetition modes (first mode with repetitions, second mode without repetitions) based on real-time conditions such as downlink pathloss, uplink signal quality, and event triggers. This dynamic adaptation allows the system to optimize coverage enhancement while minimizing collisions by switching between repetition modes according to current channel conditions.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The patent changes key parameters including the number of PRACH repetitions, selection of random access resources, and transmission power based on measured conditions such as RSRP thresholds, pathloss values, and event occurrences. By adjusting these parameters dynamically, the system achieves coverage enhancement without proportionally increasing collisions.

Inventive Principle:
Principle #35Parameter changes

2Reliability

If too many UEs select PRACH repetitions, then coverage is enhanced, but random access collisions increase

Engineering Contradiction:
Improvecoverage enhancementVSAvoidrandom access success rate
Core Design Contradiction:
ReliabilityVSProductivity

Solution Approach 1:

The patent segments the random access process into multiple independent attempts with different repetition modes. UEs can select from multiple PRACH resources and repetition configurations, distributing the load across different resources rather than concentrating all repetitions on the same resource, thereby reducing collision probability while maintaining coverage enhancement for those who need it.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The system uses feedback mechanisms where UEs measure downlink signal quality (RSRP, pathloss) and uplink signal quality, then adapt their PRACH transmission strategy accordingly. This feedback-driven adaptation allows UEs to intelligently decide when to use repetitions and which resources to select, reducing unnecessary repetitions and collisions while maintaining coverage for edge users.

Inventive Principle:
Principle #23Feedback

3Reliability

If PRACH repetitions are always performed, then coverage is improved, but unnecessary resource consumption occurs

Engineering Contradiction:
ImprovePRACH coverageVSAvoidresource consumption
Core Design Contradiction:
ReliabilityVSLoss of energy

Solution Approach 1:

The patent applies partial action by performing PRACH repetitions only when necessary - specifically when downlink pathloss exceeds a threshold, when uplink signal quality is poor, or when specific events trigger the first mode. When conditions are good, the system uses the second mode without repetitions, avoiding unnecessary resource consumption while maintaining sufficient coverage for users who need it.

Inventive Principle:
Principle #16Partial or excessive action

Data Source

PatentEP4586727A1Method and apparatus used in communication node for wireless communication
Publication Date: 2025.07.16 APOGEE 5G GLOBAL LLC
  • EP4586727A1 patent drawingFigure 1~3
  • EP4586727A1 patent drawingFigure 4~7
  • EP4586727A1 patent drawingFigure 8~13

AI summary

Disclosed in the present application are a method and apparatus used in a communication node for wireless communication. The method comprises: in response to a first event, a communication node initiating a first random access process; and sending at least a first Preamble on a first set of time-frequency resources, wherein each time-frequency resource in the first set of time-frequency resources is used for Preamble; the number of time-frequency resources comprised in the first set of time-frequency resources depends on the first event; when at least the first event belongs to a first set of candidate events, the number of time-frequency resources comprised in the first set of time-frequency resources is greater than 1; when the first event belongs to a second set of candidate events, the number of time-frequency resources comprised in the first set of time-frequency resources is equal to 1; an event in the first set of candidate events is related to initial access; and an event in the second set of candidate events is related to BFR.