Root Sequence Index Reassignment for 5G Collision Avoidance

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Solution Overview

Problem

In 5G communication systems, terminals in boundary areas or with multiple neighbor cells can experience root sequence collisions, leading to false alarms and increased access delays due to the limited number of root sequence indexes.

Innovation Solution

A network management server reassigned root sequence indexes based on statistical performance data, such as RACH-related information and handover statistics, to prevent collisions and optimize resource allocation.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Device complexity

If root sequence indexes are assigned to cells based on limited available indexes, then the assignment process is simple, but root sequence collisions occur in boundary areas or when neighbor cells exceed the number of available indexes

Engineering Contradiction:

Improveroot sequence index assignment processVSAvoidroot sequence collision probability

Core Design Contradiction:

Device complexityVSReliability

Solution Approach 1:

The patent changes the parameter of root sequence index assignment by introducing a reassignment mechanism based on statistical performance data. Instead of static assignment, the system dynamically adjusts root sequence indexes for neighbor cells using RACH-related statistics and handover information, thereby reducing collision probability while maintaining assignment simplicity

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The patent implements a feedback mechanism where the network management server collects statistical performance data (RACH success rates, handover statistics) and uses this feedback to reassess and reassign root sequence indexes. This closed-loop approach ensures that assignments are optimized based on actual network conditions, reducing collisions in boundary areas

Inventive Principle:

Principle #23Feedback

2Reliability

If root sequence collisions occur in boundary areas, then false alarms increase, but the terminal's random access delay increases

Engineering Contradiction:

Improvefalse alarm rateVSAvoidrandom access delay

Core Design Contradiction:

ReliabilityVSLoss of time

Solution Approach 1:

The patent applies preliminary action by proactively reassigning root sequence indexes before collisions cause significant problems. The network management server continuously monitors statistical performance data and performs reassignments in advance, preventing false alarms and access delays rather than reacting to them after occurrence

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The patent converts the potentially harmful effect of root sequence collisions into a benefit by using collision statistics as feedback for optimization. The system uses RACH failure rates and handover data caused by potential collisions to identify problem areas and implement targeted reassignments, thereby improving overall system performance

Inventive Principle:

Principle #22Blessing in disguise (Convert harm into benefit)

Data Source

PatentEP3573400B1Method for reassigning root sequence index and apparatus therefor

Publication Date: 2022.04.13 SAMSUNG ELECTRONICS CO LTD

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AI summary

A method for determining a root sequence index by a network management server, according to an embodiment of the disclosure, comprises the steps of: determining whether to reassign a root sequence index of a cell managed by a base station; when reassigning the root sequence index of the cell, determining the root sequence index to be reassigned to the cell on the basis of the number of handovers between the cell and adjacent cells of the cell; and transmitting the determined root sequence index to the base station.