NR PDCCH Mapping in Partial Overlap with LTE CRS

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Solution Overview

Problem

Current wireless communication systems face challenges in dynamic spectrum sharing between New Radio (NR) and Long Term Evolution (LTE) networks, particularly due to bottlenecks in NR physical downlink control channel (PDCCH) transmission and interference from LTE cell-specific reference signals (CRS), which limit resource utilization and service quality.

Innovation Solution

The implementation of techniques that allow NR PDCCH mapping and transmission in symbols overlapping with LTE CRS in the LTE frequency range, along with UE capability reporting for channel estimation and rate matching patterns, to enhance resource utilization and NR PDCCH capacity, while mitigating interference.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If NR PDCCH is transmitted in frequency regions overlapping with LTE CRS, then NR PDCCH capacity and resource utilization are improved, but interference from LTE CRS degrades signal quality

Engineering Contradiction:

ImproveNR PDCCH capacityVSAvoidinterference from LTE CRS

Core Design Contradiction:

ProductivityVSObject-affected harmful factors

Solution Approach 1:

The frequency domain is segmented into multiple regions: first frequency region where LTE PDCCH and NR PDCCH CORESET partially overlap, and second frequency region where they do not overlap. This segmentation allows different transmission strategies to be applied in different regions, enabling NR PDCCH transmission in non-overlapping regions while avoiding interference in overlapping regions.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

Different quality requirements are applied to different frequency regions. In the first frequency region where overlap occurs, LTE CRS transmission is maintained with local quality preservation. In the second frequency region where no overlap occurs, NR PDCCH can be transmitted with higher quality. This local differentiation resolves the contradiction by allowing NR PDCCH transmission only in regions where interference is absent.

Inventive Principle:

Principle #3Local quality

2Reliability

If LTE CRS is transmitted in symbols overlapping with NR PDCCH, then LTE service quality is maintained, but NR PDCCH transmission is blocked

Engineering Contradiction:

ImproveLTE service qualityVSAvoidNR PDCCH capacity

Core Design Contradiction:

ReliabilityVSProductivity

Solution Approach 1:

The system dynamically adapts NR PDCCH transmission based on the presence of LTE CRS. When LTE CRS is transmitted in a symbol, the NR PDCCH transmission is dynamically adjusted to avoid that symbol in the first frequency region. This dynamic adaptation allows LTE service quality to be maintained while maximizing NR PDCCH capacity in available resources.

Inventive Principle:

Principle #15Dynamics

Solution Approach 2:

The presence of LTE CRS, which initially appears as a harmful factor blocking NR PDCCH transmission, is converted into a beneficial signaling mechanism. The LTE CRS transmission pattern provides information about resource availability, allowing the NR system to adaptively schedule PDCCH in non-conflicting resources, thereby improving overall system coordination and resource utilization.

Inventive Principle:

Principle #22Blessing in disguise (Convert harm into benefit)

3Productivity

If NR PDCCH CORESET and LTE PDCCH frequency range are fully overlapped, then spectrum efficiency is improved, but interference and complexity increase

Engineering Contradiction:

Improvespectrum efficiencyVSAvoidresource management complexity

Core Design Contradiction:

ProductivityVSDevice complexity

Solution Approach 1:

The fully overlapped frequency domain is segmented into first and second frequency regions based on the overlap characteristics. This segmentation simplifies resource management by creating clear rules: the first region handles partial overlap with LTE PDCCH and NR PDCCH CORESET, while the second region handles non-overlapping NR PDCCH CORESET. This structured approach reduces the complexity of resource management compared to handling complete overlap uniformly.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

Instead of requiring complete overlap of NR PDCCH CORESET with LTE PDCCH frequency range, the system allows partial overlap in the first frequency region and non-overlap in the second frequency region. This partial action approach provides flexibility in resource allocation, achieving good spectrum efficiency without the full complexity and interference management burden of complete overlap.

Inventive Principle:

Principle #16Partial or excessive action

Data Source

PatentUS20240040386A1Dynamic spectrum sharing (DSS) between new radio (NR) and long term evolution (LTE)

Publication Date: 2024.02.01 APPLE INC

AI summary

A base station can support dynamic spectrum sharing (DSS) between new radio (NR) services and Long Term Evolution (LTE) services. The base station can determine whether a NR physical downlink control channel (PDCCH) control resource set (CORESET) and a LTE PDCCH frequency range are partially overlapped in a frequency domain including a first frequency region and a second frequency region. The partial overlap occurs when the LTE PDCCH frequency range overlaps with the NR PDCCH CORESET in the first frequency region without overlapping with the NR PDCCH CORESET in the second frequency region. In response to a determination that the partial overlap occurs, the base station can map a NR PDCCH or a NR PDCCH demodulation reference signal (DMRS) to resource elements in the second frequency region, and map a LTE cell-specific reference signal (CRS) to a symbol carrying the LTE CRS in the first frequency region.