UL Control Channel Structure Adaptation for Latency and Coverage Trade-offs

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Solution Overview

Problem

Future radio communication systems face challenges in accommodating diverse user terminal requirements for latency reduction, coverage, and throughput, as existing LTE systems use fixed UL control channel structures that do not adequately meet individual user terminal needs.

Innovation Solution

The implementation of multiple UL control channel structures with varying numbers of symbols allows user terminals to select the most suitable structure based on their specific requirements, enabling flexible transmission of uplink control information.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If a fixed UL control channel structure is used in existing LTE systems, then system simplicity and ease of operation are maintained, but the system cannot meet diverse user terminal requirements for latency reduction, coverage, and throughput

Engineering Contradiction:
Improveadaptability to diverse user terminal requirementsVSAvoidcomplexity of UL control channel structure
Core Design Contradiction:
Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The patent applies dynamics by making the UL control channel structure adjustable rather than fixed. The number of symbols allocated to PUCCH can be dynamically changed based on user terminal requirements, allowing the system to adapt between different service types (eMBB, mMTC, URLLC) while maintaining a unified framework. This resolves the contradiction by enabling adaptability without requiring multiple completely separate systems.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The patent changes the parameter of the number of symbols allocated to PUCCH to achieve different service requirements. By varying this parameter, the system can optimize for latency (fewer symbols), coverage (more symbols), or throughput (balanced allocation) as needed, while the underlying channel structure remains the same. This resolves the contradiction by providing adaptability through parameter adjustment rather than structural complexity.

Inventive Principle:
Principle #35Parameter changes

2Reliability

If more symbols are allocated to UL control channel, then coverage is improved, but latency increases and throughput decreases

Engineering Contradiction:
ImprovecoverageVSAvoidlatency
Core Design Contradiction:
ReliabilityVSLoss of time

Solution Approach 1:

The patent makes the symbol allocation dynamic, allowing the system to adjust the number of PUCCH symbols based on whether coverage or latency is the priority for a given user terminal and service type. This dynamic adjustment resolves the contradiction by allowing optimal allocation in different scenarios rather than being locked into a fixed allocation that must compromise between conflicting requirements.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The patent applies local quality by allowing different user terminals to have different PUCCH symbol allocations tailored to their specific requirements. User terminals requiring coverage (e.g., mMTC) can be allocated more symbols, while those requiring low latency (e.g., URLLC) can be allocated fewer symbols. This resolves the contradiction by optimizing for the local needs of each user terminal rather than applying a one-size-fits-all approach.

Inventive Principle:
Principle #3Local quality

3Loss of time

If fewer symbols are allocated to UL control channel, then latency is reduced, but coverage deteriorates

Engineering Contradiction:
ImprovelatencyVSAvoidcoverage
Core Design Contradiction:
Loss of timeVSReliability

Solution Approach 1:

The patent makes symbol allocation dynamic, allowing rapid adjustment between latency-optimized and coverage-optimized configurations. This resolves the contradiction by enabling the system to switch between fewer symbols for low latency applications and more symbols for coverage-critical applications, rather than being constrained by a fixed allocation.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The patent applies local quality by tailoring the PUCCH symbol allocation to the specific requirements of each user terminal and service type. User terminals prioritizing latency (e.g., URLLC) receive fewer symbols, while those prioritizing coverage (e.g., mMTC) receive more symbols. This resolves the contradiction by optimizing for the local priorities of each user terminal.

Inventive Principle:
Principle #3Local quality

4Adaptability or versatility

If multiple UL control channel structures with different symbol numbers are supported, then adaptability to individual user terminal needs is improved, but device complexity and resource allocation complexity increase

Engineering Contradiction:
Improveadaptability to individual user terminal needsVSAvoidcomplexity of supporting multiple structures
Core Design Contradiction:
Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The patent applies universality by designing a unified PUCCH framework that can serve multiple service types (eMBB, mMTC, URLLC) with different requirements. Instead of creating separate control channel structures for each service, the system uses a single flexible structure that can be configured with different numbers of symbols to meet diverse needs. This resolves the contradiction by providing adaptability through multi-functionality rather than through multiple separate systems.

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

5Productivity

If flexible allocation of UL control channel resources is implemented, then throughput and latency are optimized for individual services, but resource management complexity increases

Engineering Contradiction:
ImprovethroughputVSAvoidcomplexity of resource allocation
Core Design Contradiction:
ProductivityVSDevice complexity

Solution Approach 1:

The patent optimizes throughput by allowing flexible parameter adjustment of the number of PUCCH symbols. This enables the system to allocate more symbols when control information needs to be transmitted reliably (improving throughput for control channels) and fewer symbols when data transmission is prioritized. The parameter-based approach resolves the contradiction by providing simple, direct control over resource allocation without complex management mechanisms.

Inventive Principle:
Principle #35Parameter changes

Data Source

PatentEP3499828B1User terminal and wireless communication method
Publication Date: 2023.02.15 NTT DOCOMO INC
  • EP3499828B1 patent drawingFigure 1
  • EP3499828B1 patent drawingFigure 2A~2B
  • EP3499828B1 patent drawingFigure 3A~3B

AI summary

The present invention is designed to transmit uplink control information (UCI) by using UL control channels that are suitable for the requirements of user terminals in future radio communication systems. A user terminal, according to the present invention, has a transmission section that transmits uplink control information (UCI) by using an uplink (UL) control channel, and a control section that controls transmission of the UCI, and the structure of the UL control channel is selected from a plurality of structures that contain different numbers of symbols.