  In this paper, we present a practical dirty paper coding scheme using trellis
coded modulation for the dirty paper channel $Y=X+S+W,$ $\mathbb{E}\{X^2\} \leq
P$, where $W$ is white Gaussian noise with power $\sigma_w ^2$, $P$ is the
average transmit power and $S$ is the Gaussian interference with power
$\sigma_s ^2$ that is non-causally known at the transmitter. We ensure that the
dirt in our scheme remains distinguishable to the receiver and thus, our
designed scheme is applicable to broadcast channel. Following Costa's idea, we
recognize the criteria that the transmit signal must be as orthogonal to the
dirt as possible. Finite constellation codes are constructed using trellis
coded modulation and by using a Viterbi algorithm at the encoder so that the
code satisfies the design criteria and simulation results are presented with
codes constructed via trellis coded modulation using QAM signal sets to
illustrate our results.
