Determining frequency errors in a multi-carrier receiver

摘要

Individual multipath components of digital data symbols sent from a transmitter on at least two carrier frequencies generated from a common clock signal, are received (401) with individual delays and processed by a receiver unit having at least two fingers. Successive channel estimates are determined (402) from received symbols for each finger and each carrier, and an estimated frequency error is determined (404) for each finger and each carrier. A linear equation system is constructed (405), in which each determined frequency error is expressed as a function of a first variable indicative of frequency drift and a second variable indicative of frequency error caused by Doppler effect. The equation system is solved (406) to provide a solution with estimates of the first and second variables for each finger, and an estimated frequency drift is determined (407) from the solution and utilized (408) as feedback signal for adjusting receiver clock frequency.

主权项

1. A method of receiving digital data symbols sent from a transmitter on at least two carrier frequencies generated from a common clock signal, wherein individual multipath components of a transmitted data symbol are received with individual delays, and wherein received signals are processed by a receiver unit having at least two fingers, the method comprising:
determining from successively received symbols successive channel estimates for each finger and each carrier; calculating for each finger and each carrier from a set of successive channel estimates a change in channel estimate; determining from said change in channel estimate an estimated frequency error for each finger and each carrier; constructing a linear equation system corresponding to the at least two carriers and at least two fingers, in which each estimated frequency error is expressed as a function of a first variable indicative of a frequency drift caused by a clock mismatch between the receiver and the transmitter and a second variable indicative of a frequency error caused by a Doppler effect due to movement of the receiver relative to the transmitter; solving said equation system to obtain estimates of said first and second variables; determining an estimate of the frequency drift from the estimates of the first variable; and utilizing said estimate of the frequency drift as a feedback signal for adjusting the receiver clock frequency.