User equipment for detecting short codes
AssigneeInterDigital Technology Corporation
InventorsFatih M. Ozluturk, Alexander Jacques
Life of this patent
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Abstract
A receiver employing CDMA techniques estimates background noise based on a periodically updated code. The transmitted signal includes a periodically updated code of a predetermined type and wherein the received signal has CW interference in addition to the transmitted signal. The decision circuit determines if a value representing the likelihood of detection of the code exceeds a predetermined threshold. In the case of a pilot signal not being detected within a predetermined time period which corresponds to code update period, the background noise estimator obtains a new background estimation.
Claims7
A method for detecting the presence of a short code in a received signal including a plurality of periodically updated short codes, the method comprising:
- detecting the presence of a short code in the received signal using a sequential ratio probability test wherein a background noise estimation is calculated by combining a presently updated short code with the received signal,
- wherein the sequential ratio probability test comprises:
- generating a likelihood ratio by comparing the background noise estimation with the received signal;
- comparing the likelihood ratio with a first predetermined threshold;
- and,
- comparing the likelihood ratio with a second predetermined threshold on a condition that the likelihood ratio is below the first threshold, wherein the short code is present on a condition that the likelihood ratio is above the second predetermined threshold.
Dependencies are inferred from the claim text.