Interference Suppression using Nulling Filter and Turbo Equalizer for Carrier Interferometry based One-cell Reuse Single-carrier TDMA Systems

This paper proposes an interference suppression technique using nulling filter and turbo equalizer for carrier interferometry (CI) based one-cell reuse single-carrier time division multiple access (TDMA) systems. In the proposed scheme, CI technique is employed to generate CI signal which is equivalent to single carrier signal with its roll-off factor of zero. At the receiver, received CI signal is transformed into frequencydomain signal via fast Fourier transform (FFT). Interference including co-channel interference (CCI) from adjacent cell and adjacent channel interference (ACI) from the same cell is suppressed by applying frequency-domain nulling filter. After that, a soft canceller with minimum mean square error (SC/MMSE) based turbo equalizer is utilized to compensate for channel induced intersymbol interference (ISI) as well as extra ISI produced by the nulling filter. Computer simulation confirms that interference can be suppressed with the proposed scheme. Keywords-interference suppression; carrier interferometry; nulling filter; turbo equalizer