Abstract:

A new signal detection method was presented for OFDM (orthogonal frequency division multiplexing) systems with insufficient cyclic prefix (CP). The interchannel interference (ICI) and the residual intersymbol interference (ISI) could be introduced by time varying channel with channel impulse response that exceeds the length of CP, The influence mentioned above would result in error floor. The method proposed, combined with ICI cancellation, uses decisions to estimate the residual ISI through fast Fourier transform（FFT） and inverse fast Fourier transform（IFFT）, and restores the cyclicity of signals. It also can be applied with this algorithm for non-sample spaced channel with a very low computational complexity. Simulations show that the algorithm presented could provide better performance on static and slowly time-varying ISI channels.

Key words: orthogonal frequency division multiplexing, residual intersymbol interference, cyclic prefix, non-sample spaced channel