Base station for detecting short codes
AssigneeInterDigital Technology Corporation
InventorsFatih M. Ozluturk, Alexander M. Jacques
Life of this patent
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Abstract
A base station for receiving a transmitted signal in a communication system employing CDMA techniques wherein the transmitted signal includes a plurality of short codes, each of which is transmitted repetitively over a fixed period of time and where the received signal has CW interference in addition to the transmitted signal. The base station detects the presence of the short code in a plurality of time phases of the received signal by calculating a likelihood ratio for each phase. The likelihood ratio takes into account the current short code.
Claims18
A base station for receiving a transmitted signal which includes at least one short code which is periodically updated;
- the base station comprising:
- a despreader for receiving and despreading said transmitted signal to output a despread signal;
- a background noise estimator for obtaining a background noise estimation using said at least one periodically updated short code;
- and
- a decision unit, which receives said despread signal and said background noise estimate, calculates a value representing the likelihood that a short code has been detected and compares said value with a predetermined threshold;
- whereby the decision unit confirms the detection of said short code if said value exceeds said predetermined threshold.
A base station for receiving a signal transmitted by a communication unit wherein the transmitted signal includes a plurality of short codes, and the communication unit repetitively transmits at least one short code which is periodically updated, the base station comprising:
- a background noise estimator for obtaining a background noise estimation using the same periodically updated short code;
- means for utilizing said background noise estimation to adjust a likelihood ratio in accordance with the transmitted signal;
- and
- a comparator for comparing said likelihood ratio with a predetermined threshold to determine whether said likelihood ratio exceeds said predetermined threshold.
Dependencies are inferred from the claim text.