Optically Enhanced Self-Interference Cancellation for Full-Duplex Transceivers
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Solution Overview
Problem
Full-duplex wireless communication systems face challenges with self-interference due to simultaneous transmission and reception on the same channel, leading to signal degradation, and existing solutions like frequency or time division multiplexing and antenna separation are costly or inefficient.
Innovation Solution
The implementation of optically enhanced self-interference cancellation systems using both digital and analog circuitry, including photonic and optoelectronic components, to cancel self-interference without requiring additional frequencies or halving signal capacity, enabling full-duplex operation without excess cost or spectrum usage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If frequency division multiplexing is used to address self-interference, then self-interference is reduced, but spectrum usage doubles
Solution Approach 1:
The patent replaces traditional electronic self-interference cancellation systems with an optically-enhanced system. The optical system uses photodetectors and optical signal processing to generate cancellation signals, substituting electronic mechanisms with optical ones to achieve better performance without increasing spectrum usage.
Solution Approach 2:
The patent changes the domain of signal processing from electronic to optical. By converting electrical signals to optical signals for processing and then back to electrical, the system achieves superior self-interference cancellation while maintaining efficient spectrum utilization through full-duplex operation.
2Object-affected harmful factors
If time division multiplexing is used to address self-interference, then self-interference is reduced, but signal capacity is halved
Solution Approach 1:
The patent replaces electronic time-division multiplexing with an optical self-interference cancellation system that enables true full-duplex operation. The optical processing allows simultaneous transmission and reception by actively canceling self-interference in real-time, thereby maintaining full signal capacity.
Solution Approach 2:
The patent enables continuous full-duplex operation where transmission and reception occur simultaneously without time division. The optical cancellation system continuously processes and subtracts self-interference signals, allowing uninterrupted full-capacity communication in both directions.
3Object-affected harmful factors
If antenna separation techniques are used to address self-interference, then self-interference is reduced, but cost increases or space constraints are violated
Solution Approach 1:
The patent replaces physical antenna separation with an optically-enhanced electronic cancellation system. This substitution eliminates the need for large physical separations or expensive specialized antenna structures, achieving self-interference cancellation through optical signal processing instead.
Solution Approach 2:
The patent introduces an optical intermediary system between the transmitter and receiver paths. Photodetectors convert RF signals to optical signals for processing, and optical modulators convert them back, using light as an intermediary to achieve cancellation without physical separation.
4Productivity
If full-duplex operation is implemented without optically enhanced cancellation, then spectral efficiency improves, but receiver dynamic range issues worsen
Solution Approach 1:
The patent replaces conventional electronic cancellation with optically-enhanced cancellation to handle the extreme dynamic range requirements. The optical system provides higher precision signal processing that effectively removes self-interference, protecting the receiver from saturation while maintaining full-duplex spectral efficiency.
Solution Approach 2:
The patent applies preliminary cancellation of self-interference before the signal reaches the receiver. The optical system generates and subtracts cancellation signals in advance, preventing the strong transmit signal from overwhelming the receiver's dynamic range while allowing simultaneous reception.
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
This approach effectively mitigates receiver dynamic range issues and enhances spectral efficiency by allowing simultaneous transmission and reception on the same channel, improving the performance of full-duplex transceivers and relays while reducing self-interference.
Implementation Method 1
a photodetector converts the RF self-interference signal to an optical signal
Implementation Method 2
an optical modulator converts the optical signal to an electrical signal
Data Source
AI summary
An optically-enhanced relay including a first transmitter that converts a first digital transmit signal to a first analog transmit signal, a first receiver that converts a first analog receive signal to a first digital receive signal, a second transmitter that converts a second digital transmit signal to a second analog transmit signal, a second receiver that converts a second analog receive signal to a second digital receive signal, and an optically-enhanced analog self-interference canceller that generates a first self-interference cancellation signal based on at least one of the first digital transmit signal and the first analog transmit signal, and combines the first self-interference cancellation signal with at least one of the first digital receive signal and the first analog receive signal.