General differential space-time modulation

Relying on amicable orthogonal design, we develop for multiple-antenna systems a general differential space-time block code (GDSTBC), which imposes no restrictions on underlying signal constellation compared with the existing differential space-time designs. This generalization potentially allows the spectral efficiency to be increased by carrying information not only on phases but also on amplitudes. We then derive a noncoherent decoder (NCD) for flat Rayleigh fading channels. We will show that NCD may recover data symbols with full antenna diversity and linear complexity at high signal-to-noise ratio. Particularly, while three kinds of conventional signal constellations (QAM, PSK and APSK) are used in GDSTBC, we derive simplified versions of NCDs which can effectively reduce the implementation cost.