Multi-Beam Relay Self-Interference Cancellation in V2X IFD Systems

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Solution Overview

Problem

Existing mobile communication systems using a time division duplex (TDD) scheme face limitations in simultaneous transmission and reception, leading to high time delays and restricted data relay due to self-interference, which is inefficient for vehicle-to-everything (V2X) communication systems, especially in millimeter wave frequency bands.

Innovation Solution

A multi-beam based relay operating in an in-band full duplex (IFD) scheme measures signals before and after transmission to calculate self-interference, allowing for simultaneous transmission and reception by selecting the optimal beam with minimal self-interference, thereby expanding data relay capacity and reducing time delays.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a time division duplex (TDD) scheme is used to avoid self-interference, then self-interference is eliminated, but simultaneous transmission and reception cannot be achieved leading to high time delays

Engineering Contradiction:

Improveself-interference avoidanceVSAvoidtime delay

Core Design Contradiction:

ReliabilityVSLoss of time

Solution Approach 1:

The patent segments the interference problem by introducing multiple beams with different spatial directions. The relay device divides the transmission and reception operations across multiple beams, allowing simultaneous operation in different spatial domains while maintaining self-interference avoidance through beam-specific interference cancellation

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The patent introduces an interference cancellation unit as an intermediary component that processes and removes self-interference signals. This mediator enables the system to achieve both simultaneous transmission/reception and self-interference avoidance by actively canceling the interfering signals before they affect the reception

Inventive Principle:

Principle #24Intermediary (Mediator)

2Reliability

If a time division duplex (TDD) scheme is used to separate transmission and reception periods, then self-interference is avoided, but data relay capacity is restricted

Engineering Contradiction:

Improveself-interference avoidanceVSAvoiddata relay capacity

Core Design Contradiction:

ReliabilityVSProductivity

Solution Approach 1:

The patent transitions from a single-dimensional time-based separation (TDD) to a multi-dimensional approach combining space (multiple beams), frequency, and time. By utilizing multiple beams with different spatial directions, the system achieves simultaneous transmission and reception, thereby increasing data relay capacity while maintaining self-interference avoidance through spatial domain separation

Inventive Principle:

Principle #17Another dimension (Dimensionality change)

Solution Approach 2:

The patent implements dynamic beam selection and switching mechanisms that adapt to changing channel conditions and traffic requirements. The relay device can dynamically allocate different beams for transmission and reception based on real-time needs, optimizing data relay capacity while maintaining self-interference cancellation effectiveness

Inventive Principle:

Principle #15Dynamics

3Loss of time

If in-band full duplex (IFD) is used to enable simultaneous transmission and reception, then time delay is reduced, but self-interference occurs

Engineering Contradiction:

Improvetime delayVSAvoidself-interference

Core Design Contradiction:

Loss of timeVSObject-generated harmful factors

Solution Approach 1:

The patent converts the harmful self-interference signal into a measurable and cancellable component. By modeling the self-interference channel and using the known transmitted signal, the system reconstructs and subtracts the interference, effectively converting the harmful effect into a controllable parameter that can be eliminated

Inventive Principle:

Principle #22Blessing in disguise (Convert harm into benefit)

Solution Approach 2:

The patent implements a feedback mechanism where the transmitted signal is fed back through the estimated self-interference channel to generate the interference component, which is then subtracted from the received signal. This feedback-based interference cancellation enables simultaneous transmission and reception by continuously compensating for the self-interference

Inventive Principle:

Principle #23Feedback

4Productivity

If multiple beams are used in IFD scheme to reduce self-interference, then data relay capacity is expanded, but system complexity increases

Engineering Contradiction:

Improvedata relay capacityVSAvoidsystem complexity

Core Design Contradiction:

ProductivityVSDevice complexity

Solution Approach 1:

The patent segments the complex multi-beam interference cancellation problem into independent per-beam processing units. Each beam is processed separately with its own interference cancellation chain, allowing modular implementation and reducing overall system complexity through division of the processing task across multiple independent units

Inventive Principle:

Principle #1Segmentation

Data Source

PatentUS11563481B2Method and apparatus for relay based on multiple beams in vehicle-to-everything communication system

Publication Date: 2023.01.24 ELECTRONICS & TELECOMM RES INST

AI summary

An operation method of a relay operating in an in-band full duplex (IFD) scheme includes measuring a signal received from a source node during a first period; measuring a signal received from the source node and a signal received after being transmitted from the relay through a first beam during a second period, the second period being a period after a predetermined delay time from the first period; and calculating a self-interference (SI) amount of the first beam by comparing a measurement result during the second period with a measurement result during the first period.