Performance of multiple pulse position modulation on multipath channels

The effect of multipath dispersion on multiple pulse position modulation (MPPM) and its variants PPM and overlapping PPM are examined. Upper bounds for the error probability of each modulation scheme in the presence of intersymbol interference are presented, considering both an unequalised receiver and the optimal maximum-likelihood sequence detection receiver. Numerical results show that all the PPM-based schemes are approximately equally sensitive to multipath dispersion, and significantly more sensitive to multipath dispersion than on-off keying when maximum-likelihood sequence detection is used.