Wideband co-site interference cancellation based on hybrid electrical and optical techniques

Area of Science:

• Electrical Engineering
• Optical Engineering
• Signal Processing

Background:

• Co-site and co-channel interference degrade wireless signal quality.
• Existing interference cancellation systems often lack wideband capabilities.
• Efficient signal recovery is critical for robust wireless communication systems.

Purpose of the Study:

• To propose and demonstrate a wideband interference cancellation system (ICS) using hybrid electrical and optical techniques.
• To enable the recovery of weak signals of interest (SOI) from strong interfering signals.
• To achieve high cancellation depths over extensive bandwidths.

Main Methods:

• Utilized a broadband radio frequency (RF) Balun transformer for phase inversion of interfering signals.
• Employed electro-absorption modulated lasers for converting RF signals to the optical domain for fine adjustment.
• Implemented a hybrid system combining electrical and optical methods for interference subtraction.

Main Results:

• Achieved 45 dB cancellation over a 220 MHz bandwidth and over 57 dB for a 10 MHz bandwidth at 900 MHz.
• Demonstrated significant 30 dB cancellation over an exceptionally wide 5.5 GHz bandwidth.
• Successfully recovered a 10 Gb/s SOI from a 3 GHz sweeping interfering signal with error-free performance.

Conclusions:

• The proposed hybrid ICS offers unprecedented wideband cancellation performance.
• This technology is highly beneficial for scenarios with multiple interference signals across various frequency bands.
• The system demonstrates robust performance, enabling high-speed data recovery in challenging interference environments.