Self-Interference Cancellation for Concurrent ITS Radios

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Solution Overview

Problem

Concurrent operation of IEEE 802.11p and 3GPP LTE-V2X wireless communication systems in the same frequency band faces significant self-interference issues due to non-synchronized transmission and reception, leading to sensitivity degradation and interference, which requires costly and complex isolation mechanisms.

Innovation Solution

Implementing a dual radio transceiver with self-interference cancellation (SIC) techniques, including passive RF isolation, active analog RF SIC, active analog baseband SIC, and digital baseband SIC, to reduce interference between the two systems using a common antenna, by exploiting knowledge of the interfering signals and adapting SIC mechanisms based on the operating mode.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Object-affected harmful factors

If separate antennas and sharp-edge dedicated band pass filters are used to provide sufficient isolation for concurrent operation of two radio systems in the same band, then interference between systems is reduced, but material costs and system complexity increase steeply

Engineering Contradiction:

Improveinterference between radio systemsVSAvoidsystem complexity

Core Design Contradiction:

Object-affected harmful factorsVSDevice complexity

Solution Approach 1:

The patent combines multiple isolation mechanisms (passive RF isolation, active analog RF SIC, active analog baseband SIC, and digital baseband SIC) into a unified self-interference cancellation system that operates within the existing dual-radio architecture, eliminating the need for separate antennas and expensive micro-tunable filters while achieving sufficient isolation between 802.11p and LTE-V2X systems

Inventive Principle:

Principle #5Merging (Combining)

Solution Approach 2:

The patent replaces mechanical/physical isolation mechanisms (separate antennas, sharp-edge filters) with signal processing-based isolation techniques including active analog and digital self-interference cancellation algorithms that computationally eliminate interference without requiring additional physical components

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

2Object-affected harmful factors

Engineering Contradiction:

Improveinterference between radio systemsVSAvoidmaterial costs

Core Design Contradiction:

Object-affected harmful factorsVSEase of manufacture

Solution Approach 1:

The patent employs software-based and digital signal processing techniques that can be implemented through firmware or software updates rather than requiring expensive hardware components like micro-tunable filters, significantly reducing material costs while maintaining effective interference cancellation

Inventive Principle:

Principle #27Cheap short-living objects (Disposable)

Solution Approach 2:

The patent replaces expensive physical isolation components (separate antennas, sharp-edge filters) with computationally-based self-interference cancellation mechanisms that use existing hardware resources more efficiently, eliminating the need for costly additional materials

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

3Adaptability or versatility

If concurrent operation of 802.11p and LTE-V2X radios is implemented in the same frequency band, then system versatility and future compatibility are improved, but self-interference and sensitivity degradation occur

Engineering Contradiction:

Improvesystem versatilityVSAvoidsignal sensitivity

Core Design Contradiction:

Adaptability or versatilityVSReliability

Solution Approach 1:

The patent applies preliminary self-interference cancellation techniques by predicting and subtracting the interfering signal from the 802.11p transmission before it degrades the LTE-V2X reception, using knowledge of the interfering signal characteristics to pre-compensate for the interference and maintain signal sensitivity

Inventive Principle:

Principle #9Preliminary anti-action

Solution Approach 2:

The patent implements feedback-based self-interference cancellation where the system continuously monitors the interference level, adjusts the cancellation parameters dynamically, and refines the interference estimation based on the actual received signal quality, thereby maintaining reliable operation across varying conditions

Inventive Principle:

Principle #23Feedback

Data Source

PatentUS11239875B2Concurrent operation of intelligent transportation system (ITS) radios in a same frequency band with a common antenna

Publication Date: 2022.02.01 INTEL CORP

AI summary

Methods and architectures are described to allow concurrent operation of two separate, non-synchronized, radio systems utilizing closely spaced frequency bands, such as IEEE 802.11p and LTE-V2X, or NR-V2X vehicular communications systems, with a common antenna. A full duplex-“like” active interference cancellation process may be employed that includes self-interference cancellation in the RF domain, in the analog domain and the digital baseband domain to reduce complexities and costs of stringent antenna isolation, otherwise required, for a simultaneous TX and RX mode of operation and concurrent RX mode of operation in closely spaced frequency resources.