On the Wigner distribution of a class of complex spreading sequences

In this paper the time-frequency (TF) characteristics, e.g. time-varying spectrum instantaneous frequency and time spread or multipath (MP), of a class of complex perfect-squares minimum-phase (PS-MP) constant-amplitude-zero-autocorrelation (CAZAC) sequences are investigated by means of variants of the quadratic time/frequency Wigner distribution (WD), with specific emphasis on the so called pseudo Wigner distribution (PWD). An appropriate discrete PWD (DPWD) algorithm is then employed to extract characteristic channel parameters (e.g. time spread or MP and frequency spread or Doppler) of typical simulated multipath channels, from the complex probing sequences. Simulation results are presented to illustrate the advantages of the DPWD approach