Cross-Carrier Scheduling TTI Indication for LTE-A Resource Positioning

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Solution Overview

Problem

Current carrier aggregation technologies in LTE-A systems face challenges in scheduling resource blocks across carriers with different transmission time intervals (TTIs), leading to difficulties in accurately determining the position of resource blocks, which affects bandwidth utilization and peak rate requirements.

Innovation Solution

A cross-carrier scheduling method where the base station sends TTI indication information to user equipment, allowing it to accurately determine the position of resource blocks within scheduled carriers, even when TTIs differ, using techniques such as TTI identifiers, resource block numbers, or carrier indicator fields, to optimize resource allocation.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If carrier aggregation is performed on CCs with different TTIs using existing protocols, then bandwidth utilization can be improved, but user equipment cannot accurately determine the position of resource blocks in scheduled carriers

Engineering Contradiction:
Improvebandwidth utilizationVSAvoidresource block position determination accuracy
Core Design Contradiction:
ProductivityVSMeasurement precision

Solution Approach 1:

The patent introduces TTI indication information as an intermediary element carried in downlink control information to bridge the timing discrepancy between scheduling carrier and scheduled carrier. This intermediary provides the necessary timing offset information that enables UE to accurately map resource blocks across carriers with different TTIs, resolving the position determination problem while maintaining cross-carrier scheduling benefits

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The patent modifies the downlink control information structure by adding TTI indication information that changes the timing parameter representation. This allows the system to convey specific TTI offset values or indications that adapt to different TTI configurations, enabling accurate resource block positioning without requiring identical TTI structures across aggregated carriers

Inventive Principle:
Principle #35Parameter changes

2Productivity

If cross-carrier scheduling is implemented to transmit scheduling signaling of multiple CCs on a single CC, then PDCCH resource utilization is improved, but the complexity of determining resource block positions across different TTIs increases

Engineering Contradiction:
ImprovePDCCH resource utilizationVSAvoidresource block position determination complexity
Core Design Contradiction:
ProductivityVSDevice complexity

Solution Approach 1:

The TTI indication information serves as a mediator that simplifies the determination process for UE. Instead of complex calculations to align different TTI structures, the indication information provides direct timing offset values or pointers that UE can use to quickly determine resource block positions, reducing computational complexity while enabling cross-carrier scheduling

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The base station performs preliminary action by pre-calculating and indicating the TTI offset information in advance through the downlink control information. This allows UE to receive ready-made timing information before needing to determine resource block positions, eliminating the need for complex real-time calculations and reducing determination complexity

Inventive Principle:
Principle #10Preliminary action

Data Source

PatentEP3386254B1Cross-carrier scheduling methods, and apparatuses
Publication Date: 2020.10.21 HUAWEI TECH CO LTD
  • EP3386254B1 patent drawingFigure 1~2
  • EP3386254B1 patent drawingFigure 3~4
  • EP3386254B1 patent drawingFigure 5~6

AI summary

A cross-carrier scheduling method, a feedback method, and an apparatus are provided. The cross-carrier scheduling method includes: receiving, by user equipment, TTI indication information that is sent by using a scheduling carrier; and determining, by the user equipment based on the TTI indication information, a position, in a scheduled carrier, of a TTI of a subframe in which a resource block scheduled by a base station is located.