Angle differential modulation scheme for odd-bit QAM

Abstract

In this paper, a method for differential encoding of odd-bit quadrature amplitude modulation (QAM) is presented. Differential encoding would allow QAM to be transmitted over media where coherent detection is not possible owing to phase ambiguity; it would allow such a transmission without the expense of the overhead incurred in data aided transmission. An example 32-QAM constellation is proposed and the algorithms for differential encoding and decoding of the proposed constellation are presented. The analytical performance of the given scheme is also discussed and is verified using simulation results. Results of differentially encoded detection scheme are also compared with those of coherent detection. © 2012 Springer-Verlag.