Title :
Theoretical limits on time delay estimation for ultra-wideband cognitive radios
Author :
Gezici, Sinan ; Celebi, Hasari ; Arslan, Huseyin ; Poor, H. Vincent
Author_Institution :
Dept. of Electr. & Electron. Eng., Bilkent Univ., Ankara
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 nonlinearly 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.
Keywords :
cognitive radio; ultra wideband communication; Cramer-Rao lower bound; carrier-frequency offsets; channel coefficients; generic UWB spectrum; linearly modulated training signals; nonlinearly modulated training signals; time delay estimation; ultra wideband cognitive radios; Bandwidth; Cognitive radio; Contracts; Delay effects; Delay estimation; Frequency estimation; Radio transmitters; USA Councils; Ultra wideband technology; Wireless communication; Cramer-Rao lower bound (CRLB); Ultra-wideband (UWB) cognitive radio; carrier frequency offset (CFO); dispersed spectrum utilization; time delay estimation;
Conference_Titel :
Ultra-Wideband, 2008. ICUWB 2008. IEEE International Conference on
Conference_Location :
Hannover
Print_ISBN :
978-1-4244-2216-6
Electronic_ISBN :
978-1-4244-1827-5
DOI :
10.1109/ICUWB.2008.4653380
