An Interference Cancellation Scheme for TFI-OFDM in Time-Variant Large Delay Spread Channel

Abstract

In the mobile radio environment, signals are usually impaired by fading and multipath delay phenomenon. In such channels, severe fading of the signal amplitude and inter-symbol-interference (ISI) due to the frequency selectivity of the channel cause an unacceptable degradation of error performance. Orthogonal frequency division multiplexing (OFDM) is an efficient scheme to mitigate the effect of multipath channel. Since it eliminates ISI by inserting guard interval (GI) longer than the delay spread of the channel. In general, the GI is usually designed to be longer than the delay spread of the channel, and is decided after channel measurements in the desired implementation scenario. However, the maximum delay spread is longer than GI, the system performance is significantly degraded. The conventional time-frequency interferometry (TFI) for OFDM does not consider timevariant channel with large delay spread. In this paper, we focus on the large delay spread channel and propose the ISI and inter-carrier-interference (ICI) compensation method for TFI-OFDM.