A performance lower bound for quadratic timing recovery accounting for the symbol transition density
The symbol transition density in a digitally modulated signal affects the performance of practical synchronization schemes designed for timing recovery. This paper focuses on the derivation of simple performance limits for the estimation of the time delay of a noisy linearly modulated signal in the...
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| Tipo de recurso: | artículo |
| Fecha de publicación: | 2004 |
| País: | España |
| Institución: | Universitat Politècnica de Catalunya (UPC) |
| Repositorio: | UPCommons. Portal del coneixement obert de la UPC |
| Idioma: | inglés |
| OAI Identifier: | oai:upcommons.upc.edu:2117/1520 |
| Acceso en línea: | https://hdl.handle.net/2117/1520 |
| Access Level: | acceso abierto |
| Palabra clave: | Telecommunication systems Signal processing -- Digital techniques Bandlimited communication Correlation methods Delay estimation Gaussian processes Modulation Practical synchronization scheme CML Cramér-Rao bound CRB Maximum likelihood estimation Symbol transition density Quadratic timing recovery UML Noisy linearly modulated signal SNR Signal-to-noise ratio approximation Nondata-aided timing recovery Bandlimited channels Digitally modulated signal Unconditional Cramer-Rao bound Sistemes de telecomunicació Processament del senyal -- Tècniques digitals Àrees temàtiques de la UPC::Enginyeria de la telecomunicació::Processament del senyal |
| Sumario: | The symbol transition density in a digitally modulated signal affects the performance of practical synchronization schemes designed for timing recovery. This paper focuses on the derivation of simple performance limits for the estimation of the time delay of a noisy linearly modulated signal in the presence of various degrees of symbol correlation produced by the various transition densities in the symbol streams. The paper develops high- and low-signal-to-noise ratio (SNR) approximations of the so-called (Gaussian) unconditional Cramér–Rao bound (UCRB), as well as general expressions that are applicable in all ranges of SNR. The derived bounds are valid only for the class of quadratic, non-data-aided (NDA) timing recovery schemes. To illustrate the validity of the derived bounds, they are compared with the actual performance achieved by some well-known quadratic NDA timing recovery schemes. The impact of the symbol transition density on the classical threshold effect present in NDA timing recovery schemes is also analyzed. Previous work on performance bounds for timing recovery from various authors is generalized and unified in this contribution. |
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