Exploring Impact of Doppler Effect on Time-Varying Multipath Wireless Communication Channels via Model Based Characteristic Analysis

In areas of outdoor wireless communication, the Doppler shift occurs due to the relative motion between the transmitter and receiver. To apply any baseband channel model for multipath propagation, some real-world phenomena must be taken into account, such as the Doppler effect, time dispersion, and multipath scattering. Time dispersion of the radio channel leads to the Intersymbol Interference (ISI) which degrades communication performance. Scattering at diverse angles gives rise to a range of Doppler frequency shifts referred to as the Doppler spectrum. The maximum Doppler shift arises whenever the scattering direction is opposite to the channel trajectory. The Rayleigh or Rician fading distributions of the communication channel are used to characterize the line-of-sight path (LOS) and non-line-of-sight (NLOS) path radio propagation, respectively. Multipath fading causes frequency-selectivity and Doppler shifting causes time-selectivity. Two popular modeling techniques for fading channels are the Filtered White Gaussian Noise and Sum-Of-Sinusoids schemes. The impact of the Doppler effect on wireless communication channel characteristics will be examined using the model based performance analysis.