Dynamic Beam Switching and Frequency Reuse for Wireless Interference

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Solution Overview

Problem

In rich scattering environments, such as indoor and outdoor-to-indoor wireless systems, strong interferences between transmitter-receiver pairs limit the performance of wireless communication systems, and existing methods like Fractional Frequency Reuse (FFR) and beam switching struggle to mitigate interference effectively, especially due to the complex nature of radio channels.

Innovation Solution

The method involves using conflict graphs to coordinate joint beam switching and FFR techniques among base stations, determining interference levels, and adjusting beam and frequency reuse patterns dynamically to minimize interference, allowing for simultaneous illumination of multiple beams with orthogonal frequency bands.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Object-affected harmful factors

If FFR is used to mitigate interference, then interference between base stations is reduced, but spectrum efficiency decreases due to small frequency reuse factor

Engineering Contradiction:
Improveinterference between base stationsVSAvoidspectrum efficiency
Core Design Contradiction:
Object-affected harmful factorsVSProductivity

Solution Approach 1:

The patent applies dynamics by making the frequency reuse factor variable rather than fixed. The system dynamically adjusts the frequency reuse factor based on real-time interference conditions and traffic patterns, allowing it to increase when interference is high and decrease when spectrum efficiency is prioritized, thus resolving the contradiction between interference mitigation and spectrum efficiency

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The patent changes the parameter of frequency reuse factor from a static small value to a dynamic parameter that can be adjusted. By modifying this key parameter based on system conditions, the patent enables the system to achieve both interference reduction and maintained spectrum efficiency, directly addressing the technical contradiction

Inventive Principle:
Principle #35Parameter changes

2Object-affected harmful factors

If beam switching is used for coordinated beam forming, then interference suppression is improved, but gain is significantly degraded by rich scattering nature of radio channels

Engineering Contradiction:
Improvewireless interferenceVSAvoidbeam forming gain
Core Design Contradiction:
Object-affected harmful factorsVSReliability

Solution Approach 1:

The patent merges FFR and beam switching techniques into a unified interference mitigation framework. By combining these two methods, the system achieves both interference suppression and maintained beam forming gain even in rich scattering environments, overcoming the limitation where beam switching alone degrades in performance

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The patent creates a composite interference mitigation approach by integrating multiple techniques (FFR and beam switching) into a single system. This composite approach leverages the strengths of each method while compensating for their individual weaknesses, particularly maintaining effectiveness in rich scattering conditions where pure beam switching fails

Inventive Principle:
Principle #40Composite materials

3Productivity

If multiple beams are illuminated simultaneously to increase throughput, then system capacity improves, but interference between transmitter-receiver pairs increases

Engineering Contradiction:
Improvesystem throughputVSAvoidinterference between transmitter-receiver pairs
Core Design Contradiction:
ProductivityVSObject-affected harmful factors

Solution Approach 1:

The patent introduces frequency dimension as an additional degree of freedom for beam management. By allocating orthogonal frequency bands to different beams, the system enables simultaneous illumination of multiple beams without mutual interference, thus increasing system throughput while maintaining low interference levels through frequency domain separation

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

Data Source

PatentEP2529590B1Methods for reducing interference in a wireless communication system
Publication Date: 2018.06.06 ALCATEL LUCENT SA
  • EP2529590B1 patent drawingFigure 1A~1B
  • EP2529590B1 patent drawingFigure 1C
  • EP2529590B1 patent drawingFigure 2A~2C

AI summary

Example embodiments are directed to methods of reducing interference in a wireless communication system. In at least one example embodiment, a method includes first determining (S360), by a first transmitter having a multi - directional antenna configured to produce a plurality of beams, at least one interference level of at least one interfering beam of a plurality of beams of at least one transmitter in the communication system, second determining (S340) a transmitting beam pattern based on the interference level, the transmitting beam pattern indicating a sequence of illuminating the plurality of beams at corresponding time slots, third determining (S345) a fractional frequency reuse pattern based on the transmitting beam pattern, and transmitting data (S350) based on the transmitting beam pattern and the frequency reuse pattern.