ACK/NACK Channel Resource Allocation in Carrier Aggregation

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Solution Overview

Problem

In carrier aggregation systems, existing methods fail to efficiently allocate resources for ACK/NACK channel feedback, especially for non-paired uplink and downlink carriers, leading to resource waste and scheduling inflexibility.

Innovation Solution

A method and apparatus that dynamically select and notify physical channel areas for ACK/NACK channels, using LTE and LTE-A specific areas to map channels, allowing flexible scheduling and feedback of ACK/NACK messages for both paired and non-paired carriers.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of manufacture

If the single-carrier rule is applied to reserve ACK/NACK channel resources, then resource allocation is simple for paired carriers, but it becomes inapplicable and causes feedback uncertainty for non-paired carriers in carrier aggregation

Engineering Contradiction:
Improveresource allocation simplicityVSAvoidapplicability to non-paired carriers
Core Design Contradiction:
Ease of manufactureVSAdaptability or versatility

Solution Approach 1:

The patent segments the ACK/NACK resource allocation into two distinct parts: paired carriers use the traditional single-carrier rule, while non-paired carriers use a new mapping method based on downlink carrier indices. This segmentation allows each type of carrier to have its own appropriate allocation mechanism, resolving the contradiction between simplicity and adaptability.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent creates a universal resource allocation framework that can handle both paired and non-paired carriers through a unified mapping approach. The downlink carrier index-based mapping method serves as a universal solution that works for all carrier types, making the system adaptable while maintaining structured resource allocation.

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

2Reliability

If multiple Physical Uplink Control Channels (PUCCHs) are used to send confirmation information for multiple carriers, then each carrier can have independent HARQ feedback, but resource overhead increases and scheduling becomes less flexible

Engineering Contradiction:
Improveindependent HARQ feedbackVSAvoidresource overhead
Core Design Contradiction:
ReliabilityVSQuantity of substance

Solution Approach 1:

The patent merges the ACK/NACK feedback resources for multiple carriers into a unified resource pool. By mapping all ACK/NACK information to resources determined by downlink carrier indices, the system combines what would otherwise be separate PUCCH resources into a shared resource structure, reducing overall overhead while maintaining independent feedback capability.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The patent creates a universal PUCCH resource pool that serves multiple downlink carriers simultaneously. This multi-functional resource structure allows the same uplink resources to carry ACK/NACK feedback for different carriers, reducing the total quantity of resources needed while maintaining the ability to provide independent HARQ feedback for each carrier.

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

3Reliability

If ACK/NACK channel resources are reserved according to maximum CCEs, then sufficient resources are available for paired carriers, but resources are wasted when the actual number of CCEs is lower

Engineering Contradiction:
Improvesufficient resource availabilityVSAvoidresource utilization efficiency
Core Design Contradiction:
ReliabilityVSLoss of energy

Solution Approach 1:

The patent introduces dynamic resource allocation where ACK/NACK channel resources are determined based on the actual downlink carrier indices and scheduling decisions rather than static maximum CCE reservations. This dynamic approach allows resources to be allocated according to actual needs, improving utilization efficiency while maintaining sufficient availability through the flexible mapping mechanism.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The patent changes the allocation parameter from fixed maximum CCE-based reservations to dynamic downlink carrier index-based mapping. This parameter change enables the system to adapt resource allocation to actual traffic conditions and carrier configurations, reducing waste while ensuring sufficient resources are available when needed.

Inventive Principle:
Principle #35Parameter changes

Data Source

PatentEP2894806B1Method and apparatus for allocating resources and processing confirmation information
Publication Date: 2021.05.19 HUAWEI TECH CO LTD
  • EP2894806B1 patent drawingFigure 1~2
  • EP2894806B1 patent drawingFigure 3
  • EP2894806B1 patent drawingFigure 4

AI summary

A method and an apparatus for allocating ACKnowledgement (ACK)/ Non-ACKnowledgement (NACK) channel resources and processing confirmation information are disclosed. The method includes: The network side determines one physical channel area among multiple physical channel areas to be used by an ACK/NACK channel, and notifies the determined physical channel area to a User Equipment (UE) so as to enable the UE to determine a channel for receiving or sending ACK/NACK information in the determined physical channel area according to a mapping rule. Moreover, the network side may send or receive ACK/NACK information on the physical channel area that includes the ACK/NACK channel. The method and apparatus improve the utilization ratio and flexibility of the ACK/NACK channel, and reduce the probability of conflict generated by the ACK/NACK channel.