CoMP Beamforming Inter-Cell Interference Suppression

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Solution Overview

Problem

Conventional multi-user beamforming schemes in cellular networks fail to effectively exploit coordination between access points in CoMP networks, leading to significant inter-cell interference that limits spectral efficiencies and performance.

Innovation Solution

The method determines downlink transmission parameters to maximize the jointly-achievable signal-to-intra-and-inter-cell-interference-plus-noise ratio (SIINR) margin for mobile terminals under sum or per-transmitter power constraints, using iterative processes to calculate beamforming vectors and power allocations that suppress inter-cell interference across multiple access points.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If conventional multi-user beamforming schemes are used in CoMP networks, then the system can transmit data to mobile terminals, but inter-cell interference is significant and spectral efficiency is limited

Engineering Contradiction:
Improvespectral efficiencyVSAvoidinter-cell interference
Core Design Contradiction:
ProductivityVSObject-affected harmful factors

Solution Approach 1:

The patent merges the beamforming optimization of multiple access points into a unified joint optimization problem. By combining the transmit signals from multiple access points and optimizing them simultaneously based on channel state information, the system achieves coherent coordination that suppresses inter-cell interference while maintaining spectral efficiency.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The patent employs feedback mechanisms where mobile terminals provide channel state information to access points, and the system iteratively optimizes beamforming vectors and power allocations based on this feedback. This feedback loop enables the system to adapt to changing conditions and effectively manage inter-cell interference.

Inventive Principle:
Principle #23Feedback

2Productivity

If joint adaptive beamforming is applied to coordinate multiple access points, then spectral efficiency improves, but the system complexity and processing requirements increase

Engineering Contradiction:
Improvespectral efficiencyVSAvoidprocessing complexity
Core Design Contradiction:
ProductivityVSDevice complexity

Solution Approach 1:

The patent segments the joint beamforming optimization into iterative steps, where beamforming vectors and power allocations are updated separately in alternating iterations. This segmentation makes the complex optimization problem more manageable and computationally feasible while maintaining the benefits of coordinated beamforming.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent implements dynamic beamforming where the beamforming vectors and power allocations are continuously adjusted based on current channel conditions. This dynamic adaptation allows the system to optimize spectral efficiency in real-time while managing complexity through algorithmic approaches like iterative optimization.

Inventive Principle:
Principle #15Dynamics

3Reliability

If beamforming is used to improve signal quality for mobile terminals, then coverage and signal strength improve, but inter-cell interference increases

Engineering Contradiction:
Improvesignal qualityVSAvoidinter-cell interference
Core Design Contradiction:
ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The patent applies local quality optimization by tailoring beamforming vectors and power allocations to specific mobile terminals based on their individual channel conditions. Each terminal receives customized beamforming parameters that maximize its signal quality while the joint optimization ensures interference suppression in the broader context.

Inventive Principle:
Principle #3Local quality

Data Source

PatentEP2481163B1Multi-user beamforming with inter-cell interference suppression
Publication Date: 2013.07.03 TELEFONAKTIEBOLAGET LM ERICSSON (PUBL)
  • EP2481163B1 patent drawingFigure 1
  • EP2481163B1 patent drawingFigure 2~3
  • EP2481163B1 patent drawingFigure 4~5

AI summary

Techniques for determining interference-suppressing downlink transmission parameters in a wireless network using coordinated multi-point (CoMP) transmission are disclosed. In each of several iterations of an exemplary method, a tentative user- specific antenna beam-forming vector for the antennas of the first cell is formed for each of several first mobile stations served by the cell and for each of several second mobiles in neighboring cells, based on a most recent tentative virtual allocation of uplink transmitter power to each of the mobile station and virtual uplink signal-to- noise-plus-interference ratios for the mobile stations that account for inter-cell interference. Further, a current tentative allocation of downlink transmitter power to each of the first mobile stations is determined for each iteration, based on the tentative user-specific antenna beam-forming vectors for the first cell, a pre-determined transmitter power constraint for the first cell, and target signal-to-noise-plus- interference ratios for the fast mobile stations.