Orthogonalized and coded modulation for combined pulse position and pulse shape modulation

Combined pulse position and pulse shape modulation in UWB systems has been proposed. This achieves high data rates using the same number of pulses as conventional UWB systems. Due to the non uniform distribution of the modulation constellation points and the fact that these points are not orthogonal, the performance of the system suffers. We propose some methods to compensate for this performance degradation. By altering the modulation alphabet so as to obtain orthogonal points, one can expect improved performance. In addition, by applying coded modulation techniques and error correcting codes, it is possible to improve the performance of such a system significantly. Two different kinds of coding, namely Reed Solomon and trellis coding, are considered.