A new pulse shaped frequency division multiplexing technique for doubly dispersive channels

There is a growing demand for higher data rate systems that can function in a highly mobile environment. This mandates designs suited to doubly selective channels. This paper presents a pulse-shaped frequency-division multiplexing (PS-FDM) scheme for transmission over doubly-dispersive channels. The pulse shapes are designed to yield an intersymbol interference (ISI)/intercarrier interference (ICI) profile matching a given target response. The receiver relies on a high-performance/low-complexity equalizer based on the maximum likelihood (ML) criterion to reliably extract the transmitted symbols from the observations in the presence of controlled amounts of interference in the target response. In order to protect the transmitted information against subcarrier nulls, a convolutional code is used at the transmitter. The equalizer exchanges soft information with a maximum a-posteriori probability (MAP) optimal decoder in a turbo-like fashion at the receiver. Simulations suggest that turbo-equalization with the linear complexity iterative equalizer offers significant performance enhancements over standard techniques.