Real-time IBFD transmission system based on adaptive optical self-interference cancellation using the hybrid criteria regular triangle algorithm

Abstract

In this Letter, we first propose and demonstrate a real-time in-band full duplex (IBFD) transmission system based on adaptive optical self-interference cancellation (OSIC). The field programmable gate array (FPGA) is used for high-speed and real-time orthogonal frequency-division multiplexing (OFDM) transmission. The hybrid criteria regular triangle (RT) algorithm is first proposed to combine signal power and the bit error rate (BER) together as the objective function to realize the adaptive control process. With this algorithm, the real-time adaptive OSIC system is able to converge and fully recover the signal of interest (SOI) within 12 sampling times, which is by far the fastest, to the best of our knowledge, convergence under the real-time transmission scenario. Experiments show that the system can achieve 28 dB cancellation depth across 0–1.45 GHz wideband, and 40 dB cancellation depth at 900 MHz, 2.4 GHz, and 5 GHz, which is the best cancellation performance in current real-time adaptive OSIC schemes and shows the potential of our system in different commercial applications.

Photonics-assisted wideband RF self-interference cancellation with digital domain amplitude and delay pre-matching

“…To decrease the number of the iteration, the modified Hooke-Jeeves algorithm [16] and regular triangle (RT) algorithm [17] were applied to optimize the reference delay and amplitude via the tunable optical delay line (TODL) and variable optical attenuator. To achieve the SIC adaptive control with the signal of interest (SOI) [18], [19], the bit error rate of the SOI was used as the optimization parameter by using the RT algorithm. In [21], for adaptive control with more dimensions, the particle swarm optimization (PSO) algorithm was applied to optimize the phase, amplitude, and time delay of the reference signal for the photonic-assisted SIC.…”