The Gaussian assumption in second-order estimation problems in digital communications

被引:17
作者
Villares, Javier [1 ]
Vazquez, Gregori [1 ]
机构
[1] Tech Univ Catalonia, Dept Signal Theor & Commun, Barcelona, Spain
关键词
blind estimation; constant modulus; direction of arrival (DOA) estimation; estimation bounds; non-data-aided; second-order techniques; self-noise;
D O I
10.1109/TSP.2007.897872
中图分类号
TM [电工技术]; TN [电子技术、通信技术];
学科分类号
0808 ; 0809 ;
摘要
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.
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页码:4994 / 5002
页数:9
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