Estimation of the maximum Doppler spread or, equivalently, the vehicle velocity, is useful in improving handoff algorithms and necessary for the optimal tuning of parameters for systems that adapt to changing channel conditions. We provide a novel velocity estimator based on the spectral moments of the in-phase and the quadrature phase components or the envelope of the received signal. We characterize the joint effects of the Ricean K factor, the directivity and the angle of nonisotropic scattering, and the effects of additive white noise on our estimator and other covariance-based velocity estimators analytically. We also prove the mean-square consistency of the covariance-based velocity estimators under some assumptions on the angle of arrival distribution. Simulations illustrate our approach and compare with existing techniques.
Bibliographical noteFunding Information:
Manuscript received March 3, 2000; revised January 5, 2001. This work was supported by ARO Grant DAAG55-98-1-0336, ARL Grant 7850-98, and the NSF Wireless Initiative Grant 9979443. Part of the results in this paper appeared in Proceedings of the 34th Conference on Information Sciences and Systems (CISS), March 2000, and Proceedings of the Wireless Communication and Networking Conference (WCNC), September 2000.
- Fading channel models
- Velocity estimation