Computational and performance analysis of Radon transform based constellation identification

An efficient and effective method is presented for identification of the signal constellation of a voiceband or RF modem from a small number of data samples. The Radon (11917) transform based method has been shown to be more efficient than modulus based methods for identifying rectangular and hexagonal constellations with known carrier frequency and more tolerant of low SNR. When the carrier frequency is uncertain, the drift that the Radon transform method can tolerate depends on SNR, constellation size and rate of drift. The Radon transform based method is modified to greatly extend the range of carrier drift which can be tolerated with a modest increase in computation