Abstract
The automatic identification of the modulation format of a detected signal is a major task of an intelligent receiver in both military and civilian applications. It is well known that the maximum likelihood (ML) classifier requires a priori knowledge of the incoming signal and channel (including amplitude, timing information, noise power, and the roll-off factor of the pulse-shaping filter). To relax this requirement, we introduce a novel estimator to estimate the parameters required by the ML classifier which is blind to the modulation scheme of the received signal, and this gives rise to a new blind modulation classifier for digital amplitude-phase modulated signals. While the proposed classifier is completely blind, the simulation results show that the performance of this classifier is very close to the optimal non-blind classifier.



Notes
In this paper, we assume a block fading channel in which the channel amplitude and phase are constant over the N symbol observation interval.
∑ +∞k=−∞ x(t − kT) = (1/T) ∑ +∞k=−∞ X(k/T) exp (j2πkt/T), where X(f) is the Fourier transform of a function x(t).
References
Wang, F., Yang, C., Huang, S., & Wang, H. (2019). Automatic modulation classification based on joint feature map and convolutional neural network. IET Radar, 13(6), 998–1003.
Li, W., Dou, Z., Qi, L., & Shi, C. (2019). Wavelet transform based modulation classification for 5G and UAV communication in multipath fading channel. Physical Communication, 34, 272–282.
Mihandoost, S., & Azimzadeh, E. (2020). Introducing an efficient statistical model for automatic modulation classification. Journal of Signal Processing Systems, 92, 123–134.
Zhang, J., & Lv, Y. (2018). Likelihood-based automatic modulation classification in OFDM with index modulation. IEEE Transactions on Vehicular Technology, 67(9), 8192–8204.
Xu, J. L., Su, W., & Zhou, M. (2010). Likelihood-ratio approaches to automatic modulation classification. IEEE Transactions on Systems, Man, and Cybernetics Part C: Applications and Reviews, 41(4), 455–469.
Chavali, V., & DaSilva, C. (2011). Maximum-likelihood classification of digital amplitude-phase modulated signals in flat fading non-Gaussian channels. IEEE Transactions on Communications, 59(8), 2051–2056.
Panagiotou, P., Anastasopoulos, A., & Polydoros, A. (2000). Likelihood ratio tests for modulation classification. Proceedings of IEEE MILCOM, 2000, 670–674.
Dobre, O. A. et al. (2004). On the classification of linearly modulated signals in fading channels. In Proceedings of conference on information sciences and systems (CISS). Princeton University.
Kay, S. M. (2013). Fundamentals of statistical signal processing (Vol. 1). London: Pearson Education.
Dobre, O. A., & Hameed, F. (2006). Likelihood-based algorithms for linear digital modulation classification in fading channels. In Canadian conference on electrical and computer engineering. CCECE’06 (pp. 1347–1350).
Headley, W. C., & da Silva, C. R. (2011). Asynchronous classification of digital amplitude-phase modulated signals in flat-fading channels. IEEE Transactions on Communications, 59(1), 7–12.
Wei, W., & Mendel, J. M. (2000). Maximum-likelihood classification for digital amplitude-phase modulations. IEEE Transactions on Communications, 48(2), 189–193.
Zhu, Z., & Nandi, A. (2014). Blind digital modulation classification using minimum distance centroid estimator and non-parametric likelihood function. IEEE Transactions on Wireless Communications, 13(8), 4483–4494.
Van Trees, H. L. (2004). Detection, estimation, and modulation theory. London: Wiley.
Xu, J. L., Su, W., & Zhou, M. (2010). Software-defined radio equipped with rapid modulation recognition. IEEE Transactions on Vehicular Technology, 59(4), 1659–1667.
Lay, N., & Polydoros, A. (1995). Per-survivor processing for channel acquisition, data detection and modulation classification. In Proceedings of ASILOMAR (pp. 170–174).
Hameed, F., Dobre, O. A., & Popescu, D. C. (2009). On the likelihood-based approach to modulation classification. IEEE Transactions on Wireless Communications, 8(12), 5884–5892.
Mengali, U., & D’Andrea, A. N. (1997). Synchronization techniques for digital receivers. New York: Plenum Press.
Salehi, M., & Proakis, J. G. (2008). Digital communications. New York: McGraw-Hill.
Huang, S., Jiang, Y., Gao, Y., Feng, Z., & Zhang, P. (2019). Automatic modulation classification using contrastive fully convolutional network. IEEE Wireless Communications Letters, 8(4), 1044–1047.
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Amiri Ara, H., Zahabi, M.R. & Ebrahimzadeh, A. Blind Digital Modulation Identification Using an Efficient Method-of-Moments Estimator. Wireless Pers Commun 116, 301–310 (2021). https://doi.org/10.1007/s11277-020-07715-2
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DOI: https://doi.org/10.1007/s11277-020-07715-2