Analysis of Digital Self-Interference Cancellation for Different Modulation Formats

This study examines the efficacy of digital self-interference cancellation for different modulation formats within the VHF band. A conventional least-squares polynomial approach is employed as the cancellation algorithm. The interference cancellation ratio of the analog modulation formats AM, FM, and PM is compared to that of OFDM in simulations and measurements. The simulations demonstrate superior cancellation of the self-interference signal of the analog modulation formats compared to OFDM. While the AM signal can be more effectively canceled only in a highly frequency-selective channel, the FM and PM signal can be canceled by 10 dB more in all simulated channels. In the measurements, the cancellation of the OFDM signal fails completely, while the analog signals are canceled to a similar degree as in the simulations. However, the cancellation of the AM is less effective. These results suggest that the digital self-interference cancellation is more effective for narrow-band signals.