Novel multilevel modulation scheme for high capacity digital wireless access

This paper proposes a novel multilevel modulation scheme called amplitude ratio and phase modulation (ARPM). This scheme employs amplitude ratio and differential phase between two sequential transmission symbols as modulating signals. In this scheme, two amplitude ratios, one less than 1 and the other greater than 1, are allocated to one transmission symbol to avoid the conditions under which the modulated wave amplitude diverges to infinity or converges to zero. Demodulating an ARPM wave is feasible without precise level detection or accurate coherent detection even in a fast fading environment. Suitable mapping for transmission signal points in ARPM and suitable level decision for received ARPM wave are discussed. The static BER performance and the equivalent ATPC effect in ARPM are evaluated. The results confirm that ARPM is suitable for high capacity digital wireless access systems such as future broadband multimedia wireless access systems.