Propagation-medium matched direct-sequence (PM-MDS) spread-spectrum signals

The distortion of high-data-rate digital radio signals, such as direct-sequence-spread-spectrum (DS-SS) signals, when transmitted through dispersive media greatly degrades the system performance. The design of propagation-medium matched direct-sequence signals that overcome the performance degradation caused by the medium dispersion is described. The performance of PM-MDS signals in multipath dispersive media is evaluated and compared with the corresponding performance when randomly selected (unmatched) DS signals are used. The results show the advantages of PM-MDS transmission. The proposed PM-MDS signals do not require the use of sophisticated signal processing at the receiving ends, and are thus most suited for secure communication systems using one central transmitting station and numerous receiving units