【作 者】Tavares, Gonçalo N. goncalo.tavares@inesc-id.ptTavares, Luis M. miguel.tavares@estig.ipbeja.pt
【作者单位】, Beja, Portugal.GestãoIST1 Department of Electrical and Computer Engineering, Instituto Superior Técnico, Lisbon, Portugal. 2 Instituto de Engenharia de Sistemas, 1000-129 Lisbon, Portugal. 3 Department of Engineering, Escola Superior de TecnologiaESTIGINESC-IDComputadores
【摘 要】 In this paper, we present the derivation and analysis of the true Cramér-Rao lower bound (CRB) for the variance of unbiased, data-aided (DA) symbol-timing estimates, obtained from a block of K samples of a linearly modulated information signal, trans... 更多 >> In this paper, we present the derivation and analysis of the true Cramér-Rao lower bound (CRB) for the variance of unbiased, data-aided (DA) symbol-timing estimates, obtained from a block of K samples of a linearly modulated information signal, transmitted through an additive white Gaussian noise channel with random carrier phase. We consider a carrier-phase-independent time-delay estimation scenario wherein the carrier phase is viewed as an unwanted or nuisance parameter. The new bounds require only a moderate computational effort and are tighter than the CRB for the variance of unbiased time-delay estimates obtained under the assumption that the carrier phase is known. These bounds are particularly useful to assess the ultimate accuracy that can be achieved by pilot-assisted symbol synchronizers. Conversely, they may be used to evaluate data sequence suitability for the purpose of time-delay estimation. Comparison of the actual variance of a DA feedforward timing estimator with the new bounds show that these are attainable by practical synchronizers. [ABSTRACT FROM AUTHOR] << 收起
