Proposal of a time-hopping modified multipulse PPM system with restricted amplitude levels

A time-hopping modified pulse spacing modulation system with restricted amplitude levels is proposed. The proposed system combines multipulse pulse position modulation (MPPM) with code shift keying. The average frame length of the transmitted signal for the proposed system not only becomes shorter than that for the MPPM system, but the amplitude of the transmitted signal is restricted to 2 levels. The basic performance of the proposed system is evaluated by theoretical analysis. As a result, the data transmission rate of the proposed system is 2.4 times higher than that of the spread-spectrum pulse position modulation (SS-PPM) system. The probability of block error that takes into account the synchronization performance can reach the lower bound by making use of the preamble signal. Moreover, the spectral efficiency of the proposed system is 1.8 times greater than that of the SS-PPM system.