Guard Band Allocation for Downlink Transmission Interference

Resolve Bottlenecks,
Find Innovative Solutions
Generate Solutions

Solution Overview

Problem

In LTE-FDD systems, occupying the uplink frequency band for downlink transmission can cause severe interference to user equipment in adjacent frequency bands due to signal leakage, leading to resource waste and communication disruptions.

Innovation Solution

Implementing a method where a network side device determines an uplink frequency band with a guard frequency band and an available frequency band for downlink transmission, sending the downlink signal only in the available frequency band and reserving the guard frequency band at the highest or lowest part of the uplink frequency band to minimize interference.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If the base station directly sends a downlink signal in the entire uplink frequency band, then resource utilization is improved, but severe interference to user equipment in adjacent frequency bands is caused

Engineering Contradiction:
Improveresource utilizationVSAvoidinterference to adjacent frequency band
Core Design Contradiction:
ProductivityVSObject-affected harmful factors

Solution Approach 1:

The uplink frequency band is divided into two parts: a first frequency band for downlink signal transmission and a second frequency band (guard band) reserved to prevent interference. This segmentation allows the system to utilize available spectrum resources while protecting adjacent bands from harmful interference through controlled division of the frequency spectrum.

Inventive Principle:
Principle #1Segmentation

2Object-affected harmful factors

If a guard frequency band is introduced to reduce interference, then interference to adjacent frequency bands is reduced, but resource waste is caused

Engineering Contradiction:
Improveinterference to adjacent frequency bandVSAvoidresource waste
Core Design Contradiction:
Object-affected harmful factorsVSLoss of substance

Solution Approach 1:

The system dynamically adjusts the bandwidth parameters of the first and second frequency bands based on traffic conditions and interference requirements. By changing the allocation ratio between downlink transmission band and guard band, the system optimizes the balance between resource utilization and interference protection, preventing resource waste while maintaining adequate guard bands.

Inventive Principle:
Principle #35Parameter changes

3Productivity

If the uplink frequency band is occupied for downlink transmission, then resource utilization is improved, but signal leakage causes severe interference

Engineering Contradiction:
Improveresource utilizationVSAvoidsignal leakage
Core Design Contradiction:
ProductivityVSObject-generated harmful factors

Solution Approach 1:

The second frequency band acts as an intermediary buffer zone between the downlink transmission band and adjacent uplink frequency bands. This intermediary guard band absorbs and attenuates signal leakage, preventing it from reaching adjacent bands and causing interference, thus enabling safe occupation of uplink bands for downlink transmission.

Inventive Principle:
Principle #24Intermediary (Mediator)

Data Source

PatentEP3082357B1Methods and devices for performing downlink transmission
Publication Date: 2019.07.03 HUAWEI TECH CO LTD
  • EP3082357B1 patent drawingFigure 1~3
  • EP3082357B1 patent drawingFigure 4~6
  • EP3082357B1 patent drawingFigure 7~9

AI summary

This application relates to the field of wireless communications technologies, and in particular, to a method, system, and device for downlink transmission, which are used to solve a problem in the prior art that severe interference to communication of a user equipment in an adjacent frequency band may be caused when an uplink frequency band is occupied for downlink transmission. In embodiments of this application, a downlink signal is sent to a user equipment in an available frequency band of an uplink frequency band, and no signal is sent or received in a guard frequency band of the uplink frequency band, where the guard frequency band is located in a highest-frequency part and/or a lowest-frequency part of the uplink frequency band. Because no signal is sent or received in the guard frequency band of the uplink frequency band, interference to communication of a user equipment in an adjacent frequency band is reduced when the uplink frequency band is occupied for downlink transmission, thereby improving system performance.