ABSTRACT
The short term channel variations are modeled as almost pure Doppler shifts which are different for each multipath component and use this model to design the frequency-domain receivers able to deal with strong Doppler effects. These receivers can be considered as modified turbo equalizers implemented in the frequency-domain, which are able to compensate the Doppler effects associated with different groups of multipath components while performing the equalization operation. As the mobile moves over a short distance within a radio channel characterized by multipath fading, signal’s power will vary rapidly originating small-scale fading due to the sum of many different multipath components, displaced with respect to one another in time and spatial orientation, having random amplitudes and phases. The chapter describes an efficient channel tracking technique for Single Carrier with Frequency Domain Equalization transmission over fast-varying multipath channels. The multipath propagation causes time dispersion, and multiple sets of rays received with different delays are added in the receiver.
