An enhanced anti-multipath modulation approach (SDPSK/SMPDI)

Multipath fading is the main obstacle for high rate digital transmission over the indoor radio channel. The article considers an anti-multipath modulation technique called symmetrical DPSK (SDPSK) commutation signaling with a sidelobe-masked post-detection integrating receiver (SDPSK/SMPDI) over multipath channels for high rate digital transmission. It is easier to implement a post-detection integrator (PDI) receiver than a RAKE receiver. A DPSK/PDI system with a short length commutation signaling is examined. The poor shift quasiorthogonality of short sequences degrades the system dramatically. A sidelobe-masked post-detection integrating receiver (SMPDI) is presented to exploit the correlation between frames. Symmetrical DPSK commutation signaling is introduced to further reduce the adverse effect of cross-correlation sidelobes. The BER versus SNR performance for the SDPSK/SMPDI system with short sequences is close to that of the DPSK/PDI system with perfect long length commutation signaling