Theoretical limits on time delay estimation for ultra-wideband cognitive radios

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Gezici S., Celebi H., ARSLAN H., Poor H. V.

2008 IEEE International Conference on Ultra-Wideband, ICUWB 2008, Hannover, Germany, 10 - 12 September 2008, vol.2, pp.177-180 identifier identifier

  • Publication Type: Conference Paper / Full Text
  • Volume: 2
  • Doi Number: 10.1109/icuwb.2008.4653380
  • City: Hannover
  • Country: Germany
  • Page Numbers: pp.177-180
  • Keywords: Ultra-wideband (UWB) cognitive radio, time delay estimation, Cramer-Rao lower bound (CRLB), carrier frequency offset (CFO), dispersed spectrum utilization
  • Istanbul Medipol University Affiliated: Yes

Abstract

In this paper, theoretical limits on time delay estimation are studied for ultra-wideband (UWB) cognitive radio systems. For a generic UWB spectrum with dispersed bands, the Cramer-Rao lower bound (CRLB) is derived for unknown channel coefficients and carrier-frequency offsets (CFOs). Then, the effects of unknown channel coefficients and CFOs are investigated for linearly and non-linearly modulated training signals by obtaining specific CRLB expressions. It is shown that for linear modulations with a constant envelope, the effects of the unknown parameters can be mitigated. Finally, numerical results, which support the theoretical analysis, are presented. © 2008 IEEE.