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AssigneeNortel Networks Limited
InventorsChandra Sekhar Bontu, Abdulbaset Atweri Zurgani, Yonghai Gu
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The invention is a novel method enabling a base station receiver to quickly and accurately validate a coded digital verification color code (CDVCC) vector received from a mobile station against a locally stored CDVCC vector identifying the cell to which it belongs. At the base station receiver, the received signal is sampled at twice the transmitted symbol rate, producing complex-valued samples of the received symbol envelope. These contain the received CDVCC vector and a known SYNC vector, and are assumed to have undergone dispersion characterized by several dispersion coefficients. The SYNC vector is detected with relative ease, allowing the establishment of a reference sample time. This is followed by the receiver determining a plurality of possible starting times (or “shifts”) for the CDVCC vector relative to the reference sample time. These shifts preferably cover the time advances or delays that the CDVCC vector may have undergone due to dispersion, relative to the position of the SYNC vector as detected. For each of the possible shifts, the dispersion coefficients are estimated a number of times and a metric is derived, which is a measure of the variation in the estimates of the dispersion coefficients. Since the dispersion coefficients are not expected to change significantly throughout the duration of the CDVCC, a low value for the metric should be reached when the received CDVCC vector matches the locally stored CDVCC vector for at least one of the possible CDVCC vector shifts.
A method of determining the presence of a verification sequence in a received sample stream arriving at respective sample times and having a received sample rate, said verification sequence consisting of a plurality of samples including a first sample, said received sample stream being obtained from a transmitted symbol stream having a transmitted symbol rate and having undergone dispersion, said dispersion being characterized by a plurality of dispersion coefficients, the method comprising the steps of:
A system for determining the presence of a verification sequence in a received sample stream arriving at respective sample times and having a received sample rate, comprising:
A computer-readable storage medium containing software which, when running on a processor, follows a sequence of steps to determine the presence of a verification sequence in a received sample stream arriving at respective sample times and having a received sample rate, said verification sequence consisting of a plurality of samples including a first sample, said received sample stream being obtained from a transmitted symbol stream having a transmitted symbol rate and having undergone dispersion, said dispersion being characterized by a plurality of dispersion coefficients, the steps comprising:
Dependencies are inferred from the claim text.