RF Dispersive Delay Filter for Interference Cancellation
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Solution Overview
Problem
Antenna-based communication systems face inefficiencies in transmitting and receiving data on the same frequency, leading to limited spectral resource usage and interference issues, as existing interference cancellation methods do not effectively enable full duplex communication without doubling frequency spectrum usage.
Innovation Solution
An interference cancellation system incorporating an RF transmitter, an RF receiver, an electro-optical modulator, an optical-to-electrical converter, an RF dispersive delay filter, and a controllable time delay unit, which applies a phase shift and time delay to subtract interference signals, utilizing an RF dispersive delay filter with a substrate and conductive transmission line to enhance cancellation across a wide frequency band.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If two frequencies are used for uplink and downlink communication, then interference between transmission and reception is eliminated, but the amount of frequency spectrum required effectively doubles
Solution Approach 1:
The patent segments the interference cancellation process into multiple stages: optical modulation of the interference signal, photonic filtering to extract interference components, electro-optical conversion, and RF combining with the received signal. This segmentation allows sophisticated interference cancellation while operating on a single frequency, eliminating the need for frequency division duplexing.
Solution Approach 2:
The patent introduces an optical domain as an intermediary to process the RF interference signal. By converting RF interference to optical signals via electro-optical modulation, processing them through photonic filters, and converting back to RF, the system achieves advanced interference cancellation capabilities that would be difficult to implement directly in the RF domain.
2Quantity of substance
If self-interference cancellation is implemented using conventional methods, then spectrum efficiency is improved, but cancellation performance is limited across wide frequency bands
Solution Approach 1:
The patent replaces conventional electronic interference cancellation methods with a photonic-based system. By using optical modulators, photonic filters, and optical-to-electrical converters, the system achieves superior cancellation performance across wide frequency bands, overcoming the limitations of purely electronic approaches.
Solution Approach 2:
The patent creates a universal interference cancellation system that can handle multiple types of interference (self-interference, adjacent channel interference) across wide frequency bands and different waveform types. The photonic-based architecture provides frequency and waveform agnosticism, making the system adaptable to various communication standards and scenarios.
3Reliability
If photonic interference cancellation is used, then cancellation performance improves, but device complexity increases
Solution Approach 1:
The patent merges multiple functions into integrated components: the electro-optical modulator simultaneously imparts phase shifts and frequency shifts to the interference signal, the photonic filter combines filtering and signal processing functions, and the optical-to-electrical converter integrates with the RF combiner. This merging reduces the number of discrete components and simplifies the overall system architecture.
Solution Approach 2:
The patent implements self-adjusting mechanisms where the system automatically adapts to different interference conditions. The photonic-based system inherently provides frequency and waveform agnosticism, eliminating the need for manual reconfiguration when dealing with different types of interference or communication standards.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The system achieves increased interference cancellation across a wide band, allowing for efficient simultaneous transmission and reception on a single frequency, reducing spectral usage and improving communication efficiency by up to half, while maintaining frequency and waveform agnosticism up to 40 GHz.
Implementation Method 1
an electro-optical (EO) modulator configured to apply an interference cancellation phase shift to the RF interference signal
Implementation Method 2
an optical-to-electrical (OE) converter
Implementation Method 3
an RF dispersive delay filter connected to the OE converter
Data Source
AI summary
An interference cancellation system may include a radio frequency (RF) transmitter configured to generate an RF interference signal, and an RF receiver configured to receive an RF input signal that includes a signal of interest component and an RF interference signal component from the RF transmitter. The system may also include an electro-optical (EO) modulator configured to apply an interference cancellation phase shift to the RF interference signal, an optical-to-electrical (OE) converter, and an optical path between the EO modulator and OE converter. The system may also include an RF dispersive delay filter connected to the OE converter, and an RF coupler connected to the RF dispersive delay filter and the RF receiver to subtract the RF interference signal component from the RF input signal thereby producing the signal of interest component.