In this paper, a comparison is made between two different modulation/demodulation techniques, capable of offering efficient wireless data transmission. More specifically, M-ary orthogonal modulation with non-coherent demodulation, and M-ary bi-orthogonal differentially encoded modulation with differentially coherent demodulation are considered. These two modulation schemes are compared on a number of features, like: demodulator complexity, bandwidth efficiency, and bit error rate. The advantage of the M-ary bi- orthogonal differentially encoded one prevails.
Thomas J. Ketseoglou,
"Comparison of two efficient modulation schemes for wireless data applications", Proc. SPIE 2601, Wireless Data Transmission, (8 December 1995); doi: 10.1117/12.228131; http://dx.doi.org/10.1117/12.228131