The Gaussian assumption in second-order estimation problems in digital communications
PublisherIEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC
Rights accessOpen Access
This paper deals with the goodness of the Gaussian assumption when designing second-order blind estimation methods in the context of digital communications. The low- and high-signal-to-noise ratio (SNR) asymptotic performance of the maximum likelihood estimator—derived assuming Gaussian transmitted symbols—is compared with the performance of the optimal second-order estimator, which exploits the actual distribution of the discrete constellation. The asymptotic study concludes that the Gaussian assumption leads to the optimal second-order solution if the SNR is very low or if the symbols belong to a multilevel constellation such as quadrature-amplitude modulation (QAM) or amplitude-phase-shift keying (APSK). On the other hand, the Gaussian assumption can yield important losses at high SNR if the transmitted symbols are drawn from a constant modulus constellation such as phase-shift keying (PSK)or continuous-phase modulations (CPM). These conclusions are illustrated for the problem of direction-of-arrival (DOA) estimation of multiple digitally-modulated signals.
CitationVillares, J.; Vazquez, G. The Gaussian assumption in second-order estimation problems in digital communications . IEEE Transactions on Signal Processing, 2007, vol.55, núm. 10, p. 4994-5002