5G NR Subcarrier Mapping Alignment for LTE Interference

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Solution Overview

Problem

Inter-subcarrier interference occurs when 5G New Radio (NR) and Long Term Evolution (LTE) systems share a carrier due to different subcarrier mapping manners, affecting their performance and deployment timelines.

Innovation Solution

The method involves aligning NR subcarriers with LTE subcarriers by using the same subcarrier mapping manner as LTE and adjusting the frequency offset, with the base station sending indication information to the terminal to determine the correct subcarrier mapping, thereby avoiding interference and ensuring accurate frequency synchronization.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Loss of time

If NR and LTE share a carrier to enable earlier deployment and ensure coverage, then deployment time is reduced and coverage is improved, but inter-subcarrier interference occurs due to different subcarrier mapping manners

Engineering Contradiction:
Improvedeployment timeVSAvoidinter-subcarrier interference
Core Design Contradiction:
Loss of timeVSObject-affected harmful factors

Solution Approach 1:

The patent applies local quality by making the subcarrier mapping manner adaptive to the specific carrier type. When a carrier is shared between NR and LTE, the NR subcarrier mapping is locally adjusted to match LTE's mapping pattern, while NR carriers that are not shared can use the standard NR mapping manner. This localized adaptation eliminates interference on shared carriers without affecting the overall NR system design.

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

The patent changes the subcarrier mapping parameters dynamically based on whether the carrier is shared with LTE. The base station configures different subcarrier mapping parameters (such as subcarrier spacing, cyclic prefix length, and resource element allocation patterns) for shared carriers compared to dedicated NR carriers, thereby preventing interference while maintaining deployment flexibility.

Inventive Principle:
Principle #35Parameter changes

2Reliability

If different subcarrier mapping manners are used for NR and LTE, then each system can optimize its own performance, but inter-subcarrier interference occurs when they share a carrier

Engineering Contradiction:
Improvesystem performanceVSAvoidinter-subcarrier interference
Core Design Contradiction:
ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The patent introduces dynamic adaptability in subcarrier mapping by making the mapping manner dependent on the carrier sharing status. The base station can dynamically switch between different subcarrier mapping configurations based on whether LTE and NR are sharing a carrier, allowing the system to optimize performance for each specific scenario while avoiding interference through appropriate configuration selection.

Inventive Principle:
Principle #15Dynamics

Data Source

PatentEP3576363B1Method of transmitting carrier information, base station, and terminal
Publication Date: 2021.07.28 HUAWEI TECH CO LTD
  • EP3576363B1 patent drawingFigure 1~2
  • EP3576363B1 patent drawingFigure 3
  • EP3576363B1 patent drawingFigure 4

AI summary

Embodiments of this application provide a method for sending carrier information, and the method includes: performing, by a base station, subcarrier mapping on a first carrier in a first subcarrier mapping manner, where subcarriers corresponding to the first subcarrier mapping manner have frequency offset of a first offset value relative to subcarriers corresponding to a second subcarrier mapping manner, and the subcarriers corresponding to the second subcarrier mapping manner are symmetric with respect to a carrier center frequency of the first carrier, and include no subcarrier on the carrier center frequency of the first carrier; and sending, by the base station, indication information to a terminal, where the indication information carries information about the first offset value. According to the method, inter-subcarrier interference caused by different subcarrier mapping manners can be avoided.