Heterogeneous Network Interference Reduction via Uplink Signal Combining

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Solution Overview

Problem

In heterogeneous networks, inter-cell interference occurs due to link imbalances between macro cells and local nodes, such as remote radio heads (RRHs), leading to reduced communication throughput.

Innovation Solution

The carrier frequencies of macro cells and local nodes are differentiated, with the local nodes receiving and processing uplink resources from macro cells to reduce interference and enhance communication quality by combining uplink signals.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Object-affected harmful factors

If carrier frequencies of macro cells and local nodes are differentiated, then inter-cell interference is reduced, but device complexity increases due to frequency management requirements

Engineering Contradiction:
Improveinter-cell interferenceVSAvoidfrequency management complexity
Core Design Contradiction:
Object-affected harmful factorsVSDevice complexity

Solution Approach 1:

The patent changes the frequency parameter by assigning different carrier frequencies to macro cells and local nodes. This parameter change directly reduces inter-cell interference while the system manages the complexity through standardized frequency allocation procedures defined in the communication protocol

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent applies local quality by allowing local nodes to use different carrier frequencies than macro cells in specific geographic areas. This enables frequency differentiation where needed to reduce interference, while macro cells continue to operate on their standard frequencies in other areas

Inventive Principle:
Principle #3Local quality

2Productivity

If local nodes receive and process uplink resources from macro cells, then communication throughput is improved, but processing load increases

Engineering Contradiction:
Improvecommunication throughputVSAvoidprocessing load
Core Design Contradiction:
ProductivityVSPower

Solution Approach 1:

The patent merges uplink signal processing functions between macro cells and local nodes. Local nodes receive and process uplink resources from macro cells, combining the processing capabilities of both entities to improve overall communication throughput while distributing the processing load across multiple nodes

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The patent introduces local nodes as intermediary elements between user equipment and macro cells. These local nodes receive uplink signals, perform initial processing, and then forward to macro cells, which reduces the direct processing burden on macro cells while improving throughput through distributed processing

Inventive Principle:
Principle #24Intermediary (Mediator)

3Object-affected harmful factors

If local nodes handle uplink signals, then interference reduction is achieved, but system complexity increases

Engineering Contradiction:
ImproveinterferenceVSAvoidsystem complexity
Core Design Contradiction:
Object-affected harmful factorsVSDevice complexity

Solution Approach 1:

The patent segments the uplink signal handling function by assigning specific tasks to local nodes separate from macro cells. Local nodes handle uplink signal reception and initial processing, while macro cells handle higher-level coordination. This segmentation reduces interference through specialized processing while managing system complexity through clear functional division

Inventive Principle:
Principle #1Segmentation

Data Source

PatentEP3451730B1User equipment performing radio communication and base station used in a communication system
Publication Date: 2024.03.27 MITSUBISHI ELECTRIC CORP
  • EP3451730B1 patent drawingFigure 1
  • EP3451730B1 patent drawingFigure 2
  • EP3451730B1 patent drawingFigure 3

AI summary

The present invention has an object to provide a communication system of improving the communication quality in a case where a plurality of communication devices having different sizes of ranges coexist, in which communication with a terminal device is possible, to thereby improve an entire throughput. In a case where a remote radio head (RRH) is installed in a coverage of a macro cell, an uplink resource transmitted from a user equipment (UE) to the macro cell, that is, an uplink carrier frequency band UL1 of the macro cell in a portion surrounded by a solid line is received not only by the macro cell but also by the RRH. Then, the macro cell combines a reception signal regarding the uplink resource of the macro cell, which has been received by the macro cell, and a reception signal regarding the uplink resource of the macro cell, which has been received by the RRH. A base station supporting a primary cell informs the UE of timing advances for the primary cell and a secondary cell for performing radio communication via carrier aggregation simultaneously over the primary cell and the secondary cell.