Optimized impulses for multicarrier offset-QAM

The design of optimum pulses for digital multicarrier offset-QAM (MC-OQAM) is presented. The impulses are designed as finite duration pulses with maximum signal energy in one subcarrier´s frequency band. The intersymbol and intercarrier interference is minimized. The solution is obtained by expanding the impulses into finite-length discrete prolate spheroidal sequences. The design method, optimum impulses and simulation results are presented. With this technique, more than 95% of the signal energy can be concentrated in the frequency band of one subcarrier and the out-of-band spectral parts fall off very rapidly in comparison with rectangular pulses used by conventional OFDM systems. Thus, the presented multicarrier system provides much less spectral overlap between modulated subcarriers and is therefore much less susceptible against frequency-selective interference