US 7,298,806 B1 · Method and system for data-aided timing offset estimation for frequency selective fading channels

Abstract

The disclosed invention provides a system, a method and a computer program product for timing offset estimation for frequency selective fading channels in wireless communication systems. The disclosed invention first obtains a corrected received signal using the received signal and a pre-estimated timing offset. The pre-estimated timing offset is further tracked in two steps. In the first step a plurality of probable deviations in the pre-estimated timing offset are considered. Then a training sequence is used to determine an expected signal corresponding to each of the probable deviations. The corrected received signal is then shifted through the probable deviations. Thereafter error factor between the expected signals and corresponding shifted received signals is obtained. The probable deviation yielding optimum error factor is then identified as the first estimate of the deviation in timing offset. This first estimate is then refined using correlation techniques to obtain an improved estimate of the deviation.

Claims7

Dependent claims

A data-aided method of tracking the timing offset between a transmitted signal having a training sequence and a received signal using a pre-estimated timing offset, the method comprising the steps of:

a. obtaining a corrected received signal using the received signal and the pre-estimated timing offset;
b. obtaining a first estimate of the deviation in the pre-estimated timing offset out of a plurality of probable deviations by performing the steps of:
i. de-convolving the corrected received signal shifted through the first probable deviation with the training sequence to obtain an estimated channel transfer function;
ii. filtering the training sequence through the estimated transfer function to obtain an expected signal corresponding to the first probable deviation;
iii. calculating an error factor between the expected signal and the corrected received signal shifted through the first probable deviation;
performing steps i-iii for each probable deviation;
and
iv. identifying the probable deviation yielding the optimum value of error factor as the first estimate of the deviation;
and
c. obtaining an improved estimate of the deviation using the corrected received signal and the first estimate of the deviation.

7 more elements

A system for data-aided tracking of the timing offset between a transmitted signal having a training sequence and a received signal using a pre-estimated timing offset, the system comprising:

a. a pre-corrector obtaining a corrected received signal using the received signal and the pre-estimated timing offset;
b. a coarse estimator obtaining a first estimate of the deviation in the pre-estimated timing offset out of a plurality of probable deviations, the coarse estimator comprising:
i. de-convolving block de-convolving the corrected received signal shifted through a probable deviation with the training sequence to obtain an estimated channel transfer function corresponding to the probable deviation;
ii. a channel filter filtering the training sequence through the estimated channel transfer function to obtain an expected signal corresponding to the probable deviation;
iii. an error calculator calculating an error factor between the expected signal corresponding to a probable deviation and the corrected received signal shifted through the probable deviation;
and
iv. a deviation selector identifying the probable deviation yielding the optimum value of error factor as the first estimate of the deviation;
and
c. a refiner obtaining an improved estimate of the deviation using the corrected received signal and the first estimate of the deviation.

6 more elements

Dependencies are inferred from the claim text.

Method and system for data-aided timing offset estimation for frequency selective fading channels

Life of this patent

Method and system for data-aided timing offset estimation for frequency selective fading channels

Life of this patent

Abstract

Claims7