ECEN 621-600 “Mobile Wireless Networking” Course Materials: Papers, Reference Texts: Bertsekas/Gallager, Stuber, Stallings, etc Grading (Tentative): HW: 20%, Projects: 40%, Exam-1:20%, Exam-II:20% Lecture notes and Paper Reading Lists: available on-line Class Website: http://ece.tamu.edu/~xizhang/ECEN621/start.php Research Interests and Projects: URL:http://ece.tamu.edu/~xizhang Instructor: Professor Xi Zhang E-mail: xizhang@ece.tamu.edu Office: WERC 331

Characterizations and Modeling of the Wireless Channel Lecture Notes 9.

Doppler spread effect and Doppler spread function Both non-linear and time-varying system introduce new frequency components other than those existing in the input signal In wireless propagation environments, mobility of mobile users and/or surrounding scatterers, the channel is linear but time variant  introduce frequency shifts to transmitted signal This phenomenon of adding new frequency shift to transmitted signal is call Doppler Effect and introduced frequency shifts are called Doppler Shifts ECEN 621, Mobile Wireless Networks

ECEN 621, Mobile Wireless Networks Input/output model of Wireless Channel Linear time-variant (LTV) channel ECEN 621, Mobile Wireless Networks

Doppler frequency dispersion Both non-linear and time-varying system introduce new frequency components other than those existing in the input signal In wireless propagation environments, mobility of mobile users and/or surrounding scatterers, the channel is linear but time variant  introduce frequency shifts to transmitted signal This phenomenon of adding new frequency shift to transmitted signal is call Doppler Effect and introduced frequency shifts are called Doppler Shits ECEN 621, Mobile Wireless Networks

Doppler-spread function Both non-linear and time-varying system introduce new frequency components other than those existing in the input signal In wireless propagation environments, mobility of mobile users and/or surrounding scatterers, the channel is linear but time variant  introduce frequency shifts to transmitted signal This phenomenon of adding new frequency shift to transmitted signal is call Doppler Effect and introduced frequency shifts are called Doppler Shits ECEN 621, Mobile Wireless Networks