E-PDCCH Segmentation for Inter-Cell Interference Reduction

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Solution Overview

Problem

Current wireless communication systems face challenges in efficiently transmitting and receiving downlink control information, particularly in reducing inter-cell interference and optimizing resource allocation, which affects the overall performance and efficiency of the system.

Innovation Solution

The implementation of an enhanced Physical Downlink Control Channel (E-PDCCH) using transmit diversity and spatial multiplexing, along with a fallback mode for decoding the traditional PDCCH, to minimize interference and ensure robust data transmission in heterogeneous networks.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Object-affected harmful factors

If traditional PDCCH is used for downlink control information transmission, then device complexity is reduced, but inter-cell interference increases and resource allocation efficiency deteriorates

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

Solution Approach 1:

The patent segments the downlink control information transmission into two distinct channels: traditional PDCCH for basic control signals and E-PDCCH for enhanced control information. This segmentation allows the system to utilize E-PDCCH with transmit diversity and spatial multiplexing to reduce inter-cell interference, while falling back to PDCCH when E-PDCCH is not available or suitable, thus balancing interference reduction with device complexity.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent implements a dynamic switching mechanism between E-PDCCH and PDCCH based on transmission conditions. The base station dynamically determines whether to use E-PDCCH or fall back to PDCCH depending on factors such as channel conditions, interference levels, and resource availability. This dynamic adaptation allows the system to optimize performance while managing complexity according to actual operational requirements.

Inventive Principle:
Principle #15Dynamics

2Productivity

If E-PDCCH with transmit diversity and spatial multiplexing is used, then resource allocation efficiency is improved, but device complexity increases

Engineering Contradiction:
Improveresource allocation efficiencyVSAvoiddevice complexity
Core Design Contradiction:
ProductivityVSDevice complexity

Solution Approach 1:

The patent divides the control channel functionality between traditional PDCCH and enhanced E-PDCCH. E-PDCCH is specifically designed with transmit diversity and spatial multiplexing capabilities to improve resource allocation efficiency, while PDCCH handles basic control functions. This segmentation allows the system to achieve enhanced performance where needed without universally increasing complexity across all transmission scenarios.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent employs parameter changes in the form of different transmission modes for E-PDCCH. The base station can switch between transmit diversity mode and spatial multiplexing mode depending on channel conditions and resource allocation requirements. This flexibility allows the system to optimize resource utilization while adapting the complexity level to match actual transmission needs.

Inventive Principle:
Principle #35Parameter changes

3Object-affected harmful factors

If E-PDCCH is used for all downlink control information, then inter-cell interference is reduced, but reliability deteriorates due to potential decoding failures

Engineering Contradiction:
Improveinter-cell interferenceVSAvoiddecoding reliability
Core Design Contradiction:
Object-affected harmful factorsVSReliability

Solution Approach 1:

The patent implements a fallback mechanism that provides a safety net for E-PDCCH decoding failures. When the base station transmits control information via E-PDCCH, it also prepares the possibility of falling back to PDCCH if decoding fails or interference is detected. This beforehand cushioning ensures that reliability is maintained even when E-PDCCH is used to reduce inter-cell interference, as the system can switch to the more reliable PDCCH path when needed.

Inventive Principle:
Principle #11Beforehand cushioning (Prior cushioning)

Solution Approach 2:

The patent incorporates feedback mechanisms where the base station monitors the quality of E-PDCCH transmission and decoding status. Based on this feedback, the system can dynamically adjust its operation by switching between E-PDCCH and PDCCH modes. This feedback loop ensures that the system maintains high reliability by using E-PDCCH when interference reduction is beneficial and switching to PDCCH when decoding reliability becomes compromised.

Inventive Principle:
Principle #23Feedback

Data Source

PatentEP2702707B1Method for transmitting and receiving downlink control information in a wireless communication system and apparatus for the same
Publication Date: 2018.04.04 LG ELECTRONICS INC
  • EP2702707B1 patent drawingFigure 1
  • EP2702707B1 patent drawingFigure 2(a)~2(b)
  • EP2702707B1 patent drawingFigure 3

AI summary

A method for receiving a downlink signal in a user equipment of a wireless communication system from a base station comprises the steps of receiving control information from either a downlink control channel or a legacy downlink control channel in accordance with a previously set condition; and receiving a downlink shared channel or a legacy downlink shared channel on the basis of the control information, wherein the downlink control channel is received through a data region of a subframe, and the legacy downlink control channel is received through a control region of the subframe, the control information of the downlink control channel includes allocation information of the downlink shared channel, and the control information of the legacy downlink control channel includes allocation information of the downlink shared channel or the legacy downlink shared channel.