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Signal Set Design

The following binary signal set is used to transmit equally likely messages over an additive white Gaussian noise channel (spectral height $\frac{N_0}{2}$),

\begin{displaymath}\begin{array}{cc}
s_0(t) = & \left\{
\begin{array}{cl}
5 \sq...
...q t \leq T$ }\\
0 & \mbox{else}
\end{array}\right.
\end{array}\end{displaymath}

1.
Draw a block diagram of the optimum receiver.
2.
Compute the probability of error for this receiver.
3.
Repeat parts (a) and (b) for the following signal set:

\begin{displaymath}\begin{array}{cc}
s_0(t) = & \left\{
\begin{array}{cl}
7 \sq...
...q t \leq T$ }\\
0 & \mbox{else}
\end{array}\right.
\end{array}\end{displaymath}

4.
Sketch and accurately label a signal space diagram, including decision boundaries, for each of the two signal sets above.
5.
Verify that both of the above signal sets use the same average bit energy $E_b=\frac{E_0+E_1}{2}$. Then compare their performance with respect to the minimum probability of error. Explain any differences. Which signal set do you prefer?



Prof. Bernd-Peter Paris
2002-04-22