Accurate estimation of Doppler shift in mobile communications with high vehicle speed

• Published in: International journal of communication systems Vol. 27; no. 12; pp. 3515 - 3525
• Main Authors: Hua, J.Y., Yuan, D.H., Li, G., Meng, L.M.
• Format: Journal Article
• Language: English
• Published: Chichester Blackwell Publishing Ltd 01.12.2014; Wiley Subscription Services, Inc
• Subjects: Channels; Doppler effect; Doppler shift; Estimates; Estimators; high vehicle speed; Iterative methods; iterative process; level crossing rate; Level crossings; Mathematical analysis; mobile communications; Vehicles
• ISSN: 1074-5351; 1099-1131
• DOI: 10.1002/dac.2510

SUMMARYRepresenting the channel varying rate and the mobile speed of a mobile terminal directly, Doppler shift is an important parameter in vehicular mobile communications and therefore is widely used in mobile target detection and adaptive applications. Hence, this paper puts forward an accurate Doppler shift estimator in mobile communications with high vehicle speeds, which can also be treated as a vehicular speed estimator due to the well‐known relation between the Doppler shift and the mobile speed. Specifically, the proposed estimator is based on the channel level crossing rate, and an iterative process is presented to achieve signal‐to‐noise ratio (SNR) insensitive estimates in accordance with the level crossing rate estimation error analysis. Moreover, we prove the convergency of the iterative Doppler shift estimator in theory. Computer simulations conducted under a wide range of noise corruption clearly show that the proposed estimator substantially outperforms several existing estimators in terms of accuracy and achieves a good SNR‐insensitive performance in a wide range of velocities and SNRs. Copyright © 2013 John Wiley & Sons, Ltd. With the help of pilot bits and channel estimates, we calculate the level crossing rate of time‐varying channels and estimate the Doppler shift, in which an iterative process is presented to achieve the signal‐to‐noise ratio‐insensitive estimation. Moreover, the convergence of the iterative process is proved in theory. Additionally, the level crossing rate estimator does not require the series approximation and therefore produces wide Doppler shift estimation range, which must benefit the communication scenario with high vehicle speed.