Uplink Sequence Configuration for Interference Management

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Solution Overview

Problem

In future radio communication systems, the configuration of sequences for uplink control channels and reference signals is challenging due to variations in duration and start symbols, which differ from those in existing LTE systems, necessitating a flexible approach to manage inter-cell interference and frequency hopping.

Innovation Solution

The solution involves individually controlling the number of sequences applied in each slot based on whether frequency hopping is enabled, using a specific sequence index calculated from frequency hopping indices, and applying different hopping patterns and sequence shift patterns to maintain orthogonality and reduce inter-cell interference.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Object-affected harmful factors

If frequency hopping is enabled in future radio communication systems with flexible uplink control channel durations and start symbols, then inter-cell interference can be managed, but sequence configuration complexity increases

Engineering Contradiction:
Improveinter-cell interferenceVSAvoidsequence configuration complexity
Core Design Contradiction:
Object-affected harmful factorsVSDevice complexity

Solution Approach 1:

The patent applies dynamics by making the sequence configuration adaptive to frequency hopping status. The base station dynamically selects between first sequence configurations (when frequency hopping is enabled) and second sequence configurations (when frequency hopping is disabled) based on real-time channel conditions and interference requirements, allowing the system to optimize performance without fixed rigid configurations

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The patent changes sequence configuration parameters based on frequency hopping status. Different sequence configurations (with different cyclic shifts, orthogonal cover codes, and reference signal patterns) are applied depending on whether frequency hopping is enabled or disabled, allowing the system to manage interference effectively while adapting to varying operational modes

Inventive Principle:
Principle #35Parameter changes

2Productivity

If different sequence configurations are applied based on frequency hopping status, then communication efficiency is enhanced, but control signaling overhead increases

Engineering Contradiction:
Improvecommunication efficiencyVSAvoidcontrol signaling overhead
Core Design Contradiction:
ProductivityVSQuantity of substance

Solution Approach 1:

The base station pre-configures multiple sequence configuration sets and indicates to user terminals which set to use based on frequency hopping status. This preliminary preparation allows rapid switching between configurations without extensive real-time negotiation, reducing control signaling overhead while maintaining communication efficiency

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The patent creates a universal sequence configuration framework that serves multiple purposes: it manages inter-cell interference, supports both frequency hopping and non-frequency hopping modes, and accommodates different uplink control channel durations. This multi-functional approach reduces the need for separate specialized configurations, thereby reducing overall signaling overhead

Inventive Principle:
Principle #6Universality (Multi-functionality)

3Adaptability or versatility

If flexible uplink control channel durations and start symbols are supported, then system adaptability improves, but sequence orthogonality maintenance becomes more difficult

Engineering Contradiction:
Improvesystem adaptabilityVSAvoidsequence orthogonality
Core Design Contradiction:
Adaptability or versatilityVSReliability

Solution Approach 1:

The patent applies local quality by tailoring sequence configurations to specific local conditions - different uplink control channel durations, different start symbols, and different frequency hopping statuses each receive optimized sequence configurations. This localized optimization maintains orthogonality in each specific scenario while allowing overall system flexibility and adaptability

Inventive Principle:
Principle #3Local quality

Data Source

PatentEP3754926B1User terminal and wireless communication method
Publication Date: 2024.08.28 NTT DOCOMO INC
  • EP3754926B1 patent drawingFigure 1A~1B
  • EP3754926B1 patent drawingFigure 2
  • EP3754926B1 patent drawingFigure 3A~3B

AI summary

To suitably configure a sequence applied to a reference signal and/or an uplink control channel in the future radio communication systems, an aspect of a user terminal according to the present disclosure includes: a transmitting section that transmits a demodulation reference signal and/or an uplink control channel to which a certain sequence is applied in a certain slot; and a control section that selects at least one of a certain sequence applied when frequency hopping is configured and a certain sequence applied when the frequency hopping is not configured out of a plurality of certain sequences obtained on the basis of at least a frequency hopping index in each slot.