HARQ-ACK Resource Allocation for eIMTA TDD Systems

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Solution Overview

Problem

In TDD eIMTA systems, HARQ-ACK resource allocation on PUCCH faces collisions due to differing timing configurations between legacy and eIMTA UEs, leading to inefficiencies and increased overhead, particularly in dynamic UL-DL reconfiguration scenarios.

Innovation Solution

The proposed solution involves defining a new downlink association set index table that groups DL subframes into three categories: Legacy Fixed DL Subframes, Other Fixed DL Subframes, and Flexible DL Subframes, with specific ordering and indexing to minimize PUCCH resource collisions and optimize resource usage, allowing eIMTA UEs to follow a distinct association set based on their reference configuration.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Device complexity

If a single downlink association set is used for both legacy and eIMTA UEs, then resource allocation is simplified, but resource collisions occur between the two UE types

Engineering Contradiction:

Improveresource allocation complexityVSAvoidresource collision avoidance

Core Design Contradiction:

Device complexityVSReliability

Solution Approach 1:

The patent segments the downlink association set into two distinct sets: one for legacy UEs and one for eIMTA UEs. This segmentation allows each UE type to have its own dedicated resource allocation rules, eliminating resource collisions while maintaining manageable complexity through standardized segmentation logic.

Inventive Principle:

Principle #1Segmentation

2Adaptability or versatility

If dynamic UL-DL reconfiguration is implemented for eIMTA, then traffic adaptation flexibility is improved, but PUCCH overhead increases due to resource collisions

Engineering Contradiction:

Improvetraffic adaptation flexibilityVSAvoidPUCCH overhead

Core Design Contradiction:

Adaptability or versatilityVSQuantity of substance

Solution Approach 1:

By segmenting the association sets, the patent enables dynamic UL-DL reconfiguration for eIMTA UEs without causing resource collisions. This eliminates the need for additional PUCCH resources that would be required to handle collisions, thereby maintaining low PUCCH overhead while preserving traffic adaptation flexibility.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The patent uses lightweight, UE-specific association set configurations that can be dynamically adjusted without requiring substantial additional resources. These configurable parameters allow flexible reconfiguration while maintaining efficient resource usage.

Inventive Principle:

Principle #27Cheap short-living objects (Disposable)

3Reliability

If separate association sets are defined for legacy and eIMTA UEs, then resource collisions are avoided, but configuration complexity increases

Engineering Contradiction:

Improveresource collision avoidanceVSAvoidassociation set configuration

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The patent applies segmentation to create distinct association sets for legacy and eIMTA UEs, which successfully avoids resource collisions. The configuration complexity is managed through standardized segmentation rules and UE-specific parameter configurations that follow consistent patterns.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The patent manages configuration complexity by using parameter changes - specifically, UE-specific parameters that indicate which association set to use and how to interpret subframe configurations. This allows flexible configuration without requiring entirely separate complex structures.

Inventive Principle:

Principle #35Parameter changes

4Adaptability or versatility

If flexible subframes are used for dynamic reconfiguration, then traffic adaptation is improved, but HARQ timing alignment between legacy and eIMTA UEs becomes difficult

Engineering Contradiction:

Improvedynamic reconfiguration capabilityVSAvoidHARQ timing alignment

Core Design Contradiction:

Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The patent segments the handling of flexible subframes by creating separate association sets that define different timing relationships for legacy and eIMTA UEs. This allows eIMTA UEs to utilize flexible subframes for dynamic reconfiguration while legacy UEs maintain their fixed timing, avoiding alignment conflicts.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The patent uses preliminary action by pre-defining the association set configurations and timing relationships before dynamic reconfiguration occurs. This establishes clear, predetermined timing rules that both UE types can follow, simplifying HARQ timing alignment while enabling flexible subframe usage.

Inventive Principle:

Principle #10Preliminary action

Data Source

PatentUS10374774B2HARQ-ACK resource allocation and use for eIMTA

Publication Date: 2019.08.06 NOKIA SOLUTIONS & NETWORKS OY

AI summary

A downlink data transmission is performed in a downlink subframe. One or more resources are determined. The one or more resources are to be used for transmission or reception of error information for the received transmission in an uplink subframe based at least on an association set between one or more downlink or special subframes and an uplink subframe. The determined association set depends on a downlink reference configuration. The association set for each uplink subframe comprises a grouping of the downlink or special subframes into at least two groups. An association set is defined only for the subframes which are uplink subframes in a corresponding downlink reference configuration. The error information is transmitted or received using the determined one or more resources in the uplink subframe. Methods, apparatus, programs, and program products are disclosed.