TY - JOUR
T1 - Discrete time-scale characterization of wideband time-varying systems
AU - Jiang, Ye
AU - Papandreou-Suppappola, Antonia
N1 - Funding Information:
Manuscript received November 23, 2004; revised May 1, 2005. This work was supported by the National Science Foundation CAREER Award CCR-0134002. The associate editor coordinating the review of this manuscript and approving it for publication was Dr. Zidong Wang.
PY - 2006/4
Y1 - 2006/4
N2 - Wideband time-varying systems can be found in many applications, including underwater acoustics and ultra-wideband technologies. The time variation due to Doppler scaling effects, coupled with dispersive scattering due to multipath propagation, can severely limit the performance of wideband systems. Just as the discrete time-frequency model can efficiently improve narrowband processing, a discrete time-scale system characterization is important in processing wideband time-varying systems. In this paper, a time-scale model is proposed as a discrete characterization of wideband time-varying systems. This representation decomposes a wideband system output into discrete time shifts and Doppler scalings on the input signal, weighted by a smoothed and sampled version of the wideband spreading function. The proposed transform-based approach uses the Mellin transform that is inherently matched to scalings to geometrically sample the scale parameter and the Fourier transform to arithmetically sample the time-delay parameter. Using this proposed model, and by properly designing the signaling and reception schemes using wavelet techniques, a joint multipath-scale diversity can be achieved over a dyadic time-scale framework in wideband wireless systems. The simulation results demonstrate that, based on the proposed model, performance can be increased by exploiting the diversity intrinsically afforded by the wideband system.
AB - Wideband time-varying systems can be found in many applications, including underwater acoustics and ultra-wideband technologies. The time variation due to Doppler scaling effects, coupled with dispersive scattering due to multipath propagation, can severely limit the performance of wideband systems. Just as the discrete time-frequency model can efficiently improve narrowband processing, a discrete time-scale system characterization is important in processing wideband time-varying systems. In this paper, a time-scale model is proposed as a discrete characterization of wideband time-varying systems. This representation decomposes a wideband system output into discrete time shifts and Doppler scalings on the input signal, weighted by a smoothed and sampled version of the wideband spreading function. The proposed transform-based approach uses the Mellin transform that is inherently matched to scalings to geometrically sample the scale parameter and the Fourier transform to arithmetically sample the time-delay parameter. Using this proposed model, and by properly designing the signaling and reception schemes using wavelet techniques, a joint multipath-scale diversity can be achieved over a dyadic time-scale framework in wideband wireless systems. The simulation results demonstrate that, based on the proposed model, performance can be increased by exploiting the diversity intrinsically afforded by the wideband system.
KW - Mellin transform
KW - Time-frequency processing
KW - Time-scale processing
KW - Time-varying systems
KW - Wideband spreading function
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U2 - 10.1109/TSP.2006.870558
DO - 10.1109/TSP.2006.870558
M3 - Article
AN - SCOPUS:33645278686
SN - 1053-587X
VL - 54
SP - 1364
EP - 1375
JO - IEEE Transactions on Signal Processing
JF - IEEE Transactions on Signal Processing
IS - 4
ER -