On the Double Doppler Effect Generated by Scatterer Motion
Abstract
In a time-varying transmission channel, the received signals are subject to frequency shifts due to the Doppler effect. The Doppler frequency is dependent on the carrier frequency and channel variation rate. In a fixed wireless channel, the channel variations are caused by scatterer motion. In this paper, we investigate analytically the Doppler effects generated by scatterer motion under different scatterer velocity distributions using the ring-of-scatterers geometric model. The proposed model considers Doppler frequency components caused by scatterer mobility to both received and reflected signals at each scatterer, and therefore is called the double Doppler model. The analytical curves are compared and statistically tested with several measurement results published in the literature. At low scatterer speeds, e.g., generated by moving foliage, the exponential velocity distribution is an appropriate model to describe the time-varying nature of the fixed wireless channels. The curve fitting results also show that our analytical model better approaches the empirical curves than the single Doppler model does. However, further investigation is still needed to find a suitable scatterer velocity distribution that closely describes the double Doppler effect in fast-variation fixed wireless channels, e.g., caused by passing vehicles.
Published
2011-04-01
Section
Regular articles
An author's submission implies that the manuscript has not been published previously, and is not currently submitted for publication elsewhere. Submission also implies that the Corresponding Author has consent of all authors (the Authors). Upon acceptance for publication transfer of copyright will be made to the Publisher of REV-JEC, who guarantees that full content of the published article is freely distributed on the Journal's website. The copyright transfer gives the Publisher of REV-JEC full authority to resolve any complaints of misuse or abuse (such as infringement or plagiarism) of the published article. The Authors have the freedom to redistribute and reuse the published article in any medium or format for any purpose, provided the original published article is properly cited. An article submission implies author agreement with this policy.