Channel Identification and applications to OFDM communication systems with limited bandwidth

A novel channel identification algorithm is presented for OFDM communication systems in which the signal bandwidth is limited severely. Since little information outside the signal band can be extracted from the received signal directly in conventional methods, it is usually difficult to identify the channel dynamics with signal band restriction; as a result, channel identification remains large uncertainty, which leads to fragile performance of adaptive systems based on channel estimation especially outside the signal band. In order to explore much information, some specified signals are constructed and their spectral properties are analyzed by using the distinctive feature of OFDM guard interval, furthermore the spectra based identification algorithm is developed. The main computation can be performed through fast Fourier transform so the computational complexity is low. The effectiveness of the proposed approach is demonstrated by numerical simulations of channel identification and coupling cancellation in an OFDM communication relay system.