Carrier Aggregation Search Space Mapping for UL Grants and DL Assignments

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Solution Overview

Problem

In LTE-A with carrier aggregation, existing methods for mapping and encoding uplink (UL) grants and downlink (DL) assignments are not suitable for asymmetric configurations, leading to inefficiencies and increased complexity in wireless communications due to varying numbers and sizes of component carriers.

Innovation Solution

The implementation of unified methods for mapping, indicating, encoding, and transmitting UL grants and DL assignments, including one-to-one mappings, separate coding with joint transmission, and the use of radio network temporary identification (RNTI), special physical downlink control channel, carrier ID, detection orders, and dedicated search space mapping to indicate DL/UL component carriers.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If separate coding and separate transmission methods are used for UL grants and DL assignments in asymmetric carrier aggregation, then adaptability to different carrier configurations is improved, but device complexity and blind detection complexity increase

Engineering Contradiction:

Improveadaptability to asymmetric carrier configurationsVSAvoidblind detection complexity

Core Design Contradiction:

Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The patent segments the control information transmission by separating UL grants and DL assignments into different search spaces and component carriers. WTRUs monitor a first set of search spaces for UL grants on a first component carrier and a second set of search spaces for DL assignments on a second component carrier, dividing the monitoring task to reduce overall complexity while maintaining adaptability to asymmetric configurations

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The patent introduces a new dimension of control information organization by implementing separate search space sets and component carrier associations. Instead of a single unified search space, the system creates multiple search space dimensions (first search space for UL, second search space for DL) that can be independently configured and monitored, reducing blind detection complexity through dimensional separation

Inventive Principle:

Principle #17Another dimension (Dimensionality change)

2Reliability

If WTRUs monitor all component carriers for control information, then reliability of receiving UL grants and DL assignments is improved, but power consumption increases

Engineering Contradiction:

Improvereliability of control information receptionVSAvoidpower consumption

Core Design Contradiction:

ReliabilityVSUse of energy by moving object

Solution Approach 1:

The patent applies local quality by configuring WTRUs to monitor specific search spaces on specific component carriers based on their assignment type. Instead of uniformly monitoring all component carriers, the system enables targeted monitoring where WTRUs only search for UL grants in the first search space set on the first component carrier and DL assignments in the second search space set on the second component carrier, reducing power consumption while maintaining reliability

Inventive Principle:

Principle #3Local quality

Solution Approach 2:

The system performs preliminary configuration of search space sets and component carrier associations before actual control information transmission. By pre-configuring which search spaces correspond to UL grants and which correspond to DL assignments on specific component carriers, WTRUs can efficiently target their monitoring efforts without exhaustive searching, reducing power consumption while ensuring reliable reception

Inventive Principle:

Principle #10Preliminary action

3Quantity of substance

If unified mapping methods are implemented for UL grants and DL assignments, then overhead is reduced, but adaptability to asymmetric configurations deteriorates

Engineering Contradiction:

Improvecontrol overheadVSAvoidadaptability to asymmetric carrier configurations

Core Design Contradiction:

Quantity of substanceVSAdaptability or versatility

Solution Approach 1:

The patent implements a universal mapping framework where the same search space set structure and component carrier association mechanisms can handle both UL grants and DL assignments. The first search space set and second search space set use consistent configuration parameters and mapping rules, reducing overhead through unified methodology while maintaining adaptability to asymmetric configurations through flexible association with different component carriers

Inventive Principle:

Principle #6Universality (Multi-functionality)

Data Source

PatentUS12563567B2Uplink grant, downlink assignment and search space method and apparatus in carrier aggregation

Publication Date: 2026.02.24 INTERDIGITAL PATENT HOLDINGS INC

AI summary

Methods of mapping, indicating, encoding and transmitting uplink (UL) grants and downlink (DL) assignments for wireless communications for carrier aggregation are disclosed. Methods to encode and transmit DL assignments and UL grants and map and indicate the DL assignments to DL component carriers and UL grants to UL component carriers are described. Methods include specifying the mapping rules for DL component carriers that transmit DL assignment and DL component carriers that receive physical downlink shared channel (PDSCH), and mapping rules for DL component carriers that transmit UL grants and UL component carriers that transit physical uplink shared channel (PUSCH) when using separate coding/separate transmission schemes.