Title :
Spectrum analysis using a trellis algorithm
Author :
Feng Rice ; Cowley, Bill ; Rice, Feng ; Moran, Bill
Author_Institution :
Dept. of Math., Flinders Univ. of South Australia, Bedford Park, SA, Australia
Abstract :
Carrier frequency offset is a significant problem in achieving signal acquisition in communications equipment. In a receiver the frequency offset must be corrected before symbol timing and phase recovery operations can be completed. Several methods have been applied to frequency estimation, for example, the fast Fourier transform (FFT) method and the differential phase method. However, the FFT method suffers from threshold effects and the differential phase method, although simple, suffers an SNR penalty though its differential detection and is sensitive to large frequency offsets. This paper describes a trellis based scheme for frequency and phase estimation. A recently reported technique, per-survivor processing (Raheli, 1995) has been adapted to make use of the trellis structure and is described. The technique, referred to herein as frequency estimation by PSP (FEPSP), gives near optimum performance under certain conditions. Firstly Cramer-Rao lower bounds (CRLB) are derived for the frequency estimator and the phase estimator. The PSP estimation algorithm is then described. Lastly, the performance of the FEPSP is discussed and compared with that of the CRLB and FFT methods
Keywords :
frequency estimation; phase estimation; signal detection; spectral analysis; Cramer-Rao lower bounds; FEPSP; FFT; carrier frequency offset; communications equipment; differential phase method; fast Fourier transform; frequency estimation by PSP; initial phase; near optimum performance; per-survivor processing; phase recovery; signal acquisition; spectrum analysis; symbol timing; trellis algorithm; trellis based scheme; Algorithm design and analysis; Doppler shift; Frequency estimation; Low earth orbit satellites; Mathematics; Phase estimation; Radio communication; Radio transmitters; Receivers; Signal to noise ratio;
Conference_Titel :
Signal Processing Proceedings, 1998. ICSP '98. 1998 Fourth International Conference on
Conference_Location :
Beijing
Print_ISBN :
0-7803-4325-5
DOI :
10.1109/ICOSP.1998.770942