Interference Suppression Technique using Edge-removal Filter, Nulling Filter and Turbo Equalizer for Single Carrier Based Broadband Wireless Transmission

This paper proposes an interference suppression technique using edge-removal filter in the transmitter, as well as, nulling filter and turbo equalizer in the receiver for carrier interferometry (CI) based one-cell reuse single-carrier time division multiple access (TDMA) systems. In the proposed system, the desired signals in the reference cell are interfered by interference including adjacent-channel interference (ACI), cochannel interference (CCI) and intersymbol interference (ISI). At the transmitter, a CI technique is employed to generate CI signal which is equivalent to single-carrier signal with its roll-off factor of zero. After that, ACI components are eliminated by edge-removal filter. At the receiver, the received signal is transformed into frequency-domain signal by a fast Fourier transform (FFT). Co-channel interference (CCI) from adjacent cell is suppressed by applying a frequency-domain nulling filter. Then 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 the proposed scheme can effectively suppress ACI, CCI and ISI. Keywords-interference suppression; carrier interferometry; edge-removal filter; nulling filter; turbo equalizer