Experimental Validations on Self Interference Cancelled Non-Orthogonal SEFDM Signals

Spectral efficiency can be improved in multicarrier systems through the employment of non-orthogonal overlapping sub-carriers, termed spectrally efficient frequency division multiplexing (SEFDM), but with self-created interference. Previous work has focused on signal detection development. The trade-off between performance and complexity is challenging. This work investigates a self interference cancellation scheme for SEFDM to make use of ICI information at the transmitter and simplify the design of receiver. Repetition codes are used in the system where the same symbol with opposite signs are modulated onto adjacent sub-carriers. Therefore, ICI caused by adjacent sub-carriers would be cancelled mutually. However, the spectral efficiency is reduced. In order to maintain the same spectral efficiency and mutual interference cancellation benefits, the optimal combination of various modulation formats and bandwidth compression factors have to be studied jointly to derive maximum achievable spectral efficiency. Both simulation and experiment are reported and results validate the performance of the proposed self interference cancellation scheme.