Jindal, NiharLozano Solsona, AngelUniversitat Pompeu Fabra2011-11-112011-11-112010Jindal N, Lozano A. A unified treatment of optimum pilot overhead in multipath fading channels. IEEE transactions on communications. 2010; 58(10): 2939-2948. DOI 10.1109/TCOMM.2010.083110.0906960090-6778http://hdl.handle.net/10230/13027The optimization of the pilot overhead in single-user wireless fading channels is investigated, and the dependence of this overhead on various system parameters of interest (e.g., fading rate, signal-to-noise ratio) is quantified. The achievable pilot-based spectral efficiency is expanded with respect to the fading rate about the no-fading point, which leads to an accurate order expansion for the pilot overhead. This expansion identifies that the pilot overhead, as well as the spectral efficiency penalty with respect to a reference system with genie-aided CSI (channel state information) at the receiver, depend on the square root of the normalized Doppler frequency. It is also shown that the widely-used block fading model is a special case of more accurate continuous fading models in terms of the achievable pilot-based spectral efficiency. Furthermore, it is established that the overhead optimization for multiantenna systems is effectively the same as for single-antenna systems with the normalized Doppler frequency multiplied by the number of transmit antennas.application/pdfeng© 2010 IEEE. Personal use of this material is permitted. Permission from IEEE must be obtained for all other uses, in any current or future media, including reprinting/republishing this material for advertising or promotional purposes, creating new collective works, for resale or redistribution to servers or lists, or reuse of any copyrighted component of this work in other works./nThe final published article can be found at http://ieeexplore.ieee.org/xpls/abs_all.jsp?arnumber=5567190Doppler, EfecteComunicació sense fil, Sistemes deRàdio -- Antenesinfo:eu-repo/semantics/articlehttp://dx.doi.org/10.1109/TCOMM.2010.083110.090696MIMOSpectral efficiencyChannel estimationDoppler spectrumMultiantennaMutual informationinfo:eu-repo/semantics/openAccess