Optimum receiver design for wireless broad-band systems using OFDM - Part I

Orthogonal frequency-division multiplexing (OFDM) is the technique of choic e in digital broad-band applications that must cope with highly dispersive transmission media at low receiver implementation cost. In this paper, we f ocus on the inner OFDM receiver and its functions necessary to demodulate t he received signal and deliver soft information to the outer receiver for d ecoding, In Part I of this paper, the effects of relevant nonideal transmis sion conditions are thoroughly analyzed: imperfect channel estimation, symb ol frame offset, carrier and sampling clock frequency offset, time-selectiv e fading, and critical analog components. Through an appropriate optimizati on criterion (signal-to-noise ratio loss), minimum requirements on each rec eiver synchronization function are systematically derived, An equivalent si gnal model encompassing the effects of all relevant imperfections is then f ormulated in a generalized framework. Part I concludes with an outline of s ynchronization strategies to be detailed in Part II.