Carrier Identification via PDCCH Position Mapping in Cross-Carrier Scheduling

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Solution Overview

Problem

In wireless communication systems with carrier aggregation, terminals struggle to determine the target carrier when downlink control information (DCI) lacks a carrier indicator field (CIF), hindering proper cross-carrier scheduling operations.

Innovation Solution

Terminals and network devices agree on rules to determine the target carrier based on cross-carrier related information and PDCCH candidate resource positions, using RRC parameters or predefined protocols, even when DCI lacks a CIF.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Device complexity

If DCI does not include carrier indicator information, then the DCI format is simplified and can be used for scheduling without CIF, but the terminal cannot determine the carrier index indicated by the DCI

Engineering Contradiction:

ImproveDCI format complexityVSAvoidcarrier index information

Core Design Contradiction:

Device complexityVSLoss of information

Solution Approach 1:

The patent introduces an intermediary mechanism (predefined mapping rules between PDCCH candidate positions and carrier indices) that allows the terminal to infer carrier index information without it being explicitly transmitted in the DCI. The PDCCH candidate resource position acts as a mediator that carries implicit carrier identification information.

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The patent changes the parameter representation method by encoding carrier index information in the PDCCH candidate position parameter rather than in the DCI payload. This allows the same carrier index information to be conveyed through a different parameter (resource position) that does not increase DCI format complexity.

Inventive Principle:

Principle #35Parameter changes

2Ease of operation

If the terminal monitors PDCCH on the scheduling carrier only, then the terminal can simplify its monitoring operations, but the terminal cannot perform cross-carrier scheduling when DCI lacks CIF

Engineering Contradiction:

ImprovePDCCH monitoring operationVSAvoidcross-carrier scheduling capability

Core Design Contradiction:

Ease of operationVSAdaptability or versatility

Solution Approach 1:

The patent applies preliminary action by pre-configuring mapping rules between PDCCH candidate positions and carrier indices before cross-carrier scheduling operations. This allows the terminal to have ready-made determination rules that enable versatile cross-carrier scheduling while maintaining simple monitoring operations.

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The patent makes the PDCCH monitoring mechanism universal by designing a determination rule that works for both same-carrier and cross-carrier scheduling scenarios. The same PDCCH monitoring approach can identify target carriers through the established mapping rules, providing multi-functionality without requiring separate monitoring mechanisms.

Inventive Principle:

Principle #6Universality (Multi-functionality)

Data Source

PatentEP4106453B1Indication method, terminal, and network device

Publication Date: 2026.04.01 DATANG MOBILE COMM EQUIP CO LTD

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AI summary

The present disclosure provides an indication method, a terminal and a network device. The method includes: receiving DCI sent by a network device, wherein the DCI does not include a CIF; determining a target carrier corresponding to the DCI, according to a rule agreed with the network device.