  In this paper, Gaussian two-way channel with uniform output quantization is
studied. For Gaussian inputs, the optimum uniform finite-level quantizer is
determined numerically for different values of Signal-to-Noise Ratio (SNR). The
two-way channel with constellation-based transmitters is then investigated. A
formulation for the so-called Shannon achievable region of this channel is
developed and numerical computations of this region are presented for
particular constellations. It is shown that if one transmitter utilizes a
rotated version of the constellation used at the other transmitter, the Shannon
achievable region can be enlarged
