Modulation identification by general orthogonal modulations

A family of orthogonal modulations is widely spread in a variety of communication applications. These modulations include orthogonal frequency division multiplexing (OFDM), orthogonal code division multiple access (CDMA), a block of quadrature amplitude modulation (QAM), and so on. General orthogonal modulation was developed for the design of new flexible modulations by a multidimensional rotation, where the rotation planes and angles are the modulation parameters. In this paper, an identification of these orthogonal modulations is presented. The identification method is based on general orthogonal modulations [1], whose modulation parameters should be estimated. A set of orthonormal vectors is obtained by received signal samples, and is used to estimate the modulation parameter of general orthogonal modulations. Computer simulations are executed to show a validity of the identification method. Bit error probability of the estimated modulation is given for 3-8 dimensional orthogonal modulations as illustrative examples.