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Unformatted text preview: matrices above a priori,
we can send a training sequence to facilitate the estimation of them. 4.4 Maximum Likelihood Sequence Receiver
Whenever it is not practical to construct ISI-free transmission pulses, we can use an equalizer to
eliminate (or reduce) ISI, and then make a decision on the current symbol based on the equalizer
output. Although this approach is simple and practical, we have no idea whether it is optimal in
terms of minimizing the average symbol error probability. In fact, it turns out that all the equalization
methods discussed in the previous section are not optimal. Because of the fact that the effect of a
symbol is spread to other symbols, it is intuitive that the optimal receiver should observe not only the
segment of received signal concerning the desired symbol, but the whole received signal instead. As
a matter of fact, this strategy is also employed in the equalization techniques described previously7.
Using the whole received signal, we can employ the MAP principle to develop the optimal symbolby-sym...
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This note was uploaded on 12/13/2012 for the course EEL 6535 taught by Professor Shea during the Spring '08 term at University of Florida.
- Spring '08