On Discrete-Time Modeling of Time-Varying WSSUS Fading Channels

• Published in: IEEE transactions on vehicular technology Vol. 59; no. 7; pp. 3645 - 3651
• Main Authors: Sgraja, C, Jun Tao, Chengshan Xiao
• Format: Journal Article
• Language: English
• Published: New York, NY IEEE 01.09.2010; Institute of Electrical and Electronics Engineers; The Institute of Electrical and Electronics Engineers, Inc. (IEEE)
• Subjects: 3G mobile communication; Applied sciences; Approximation; Approximation methods; Bandwidth; Channels; Computer simulation; Concatenated codes; Detection, estimation, filtering, equalization, prediction; Digital filters; discrete-time systems; Equipments and installations; Error analysis; Exact sciences and technology; Fading; fading channels; Filtering; Information, signal and communications theory; Mathematical analysis; Mathematical models; Mobile radiocommunication systems; Nonlinear filters; Numerical simulation; Radiocommunications; Scattering; Signal and communications theory; Signal, noise; Spreads; system modeling; Systems, networks and services of telecommunications; Telecommunications; Telecommunications and information theory; time-varying systems; Transmission and modulation (techniques and equipments); discrete-time systems; time-varying systems; Error analysis; Error estimation; Wireless telecommunication; Linear time; Approximation methods; Modeling; Time variation; system modeling; Digital system; Time varying system; Accuracy; Fading channels; Mobile radiocommunication; Filtering; Approximate method; Discrete time systems; Digital transmission; Concatenation; Time domain method; Discrete time; UMTS system; Numerical simulation; System simulation
• DOI: 10.1109/TVT.2010.2054121
• ISSN: 0018-9545

The general property of noncommutativity of linear time-varying (LTV) systems has to be considered when a digital transmission system composed of LTV channel and transmit/receive filtering shall be represented in the equivalent discrete-time domain. In this correspondence, we analyze the implications of serially concatenated LTV systems with respect to the discrete-time representation of wide-sense stationary uncorrelated scattering (WSSUS) fading channels. We provide a detailed discussion of the largest tolerable channel Doppler spread (in relation to the system bandwidth) for which the concatenation is commutative in good approximation. In this case, the discrete-time description facilitates an efficient simulation model. The approximation accuracy is quantified by a detailed error analysis and further verified by numerical simulation adopting Universal Mobile Telecommunications System (UMTS) parameters.