Method for searching pilot signals to synchronize a CDMA receiver with an associated transmitter
First Claim
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1. A method for synchronizing a receiver having an adaptive antenna to a transmitter, comprising the steps of:
- adapting the antenna to an omni-directional pattern;
checking PN offsets of a transmitted pilot signal;
storing PN offsets of the transmitted pilot signal which produce valid correlations of PN offsets;
reloading each PN offset which produced the valid correlations of the PN offsets;
steering the antenna to a directional pattern; and
monitoring a correlation value of the PN offset which produced a valid correlation of a PN offset while adapting the antenna to the directional pattern to synchronize the receiver to a strongest transmitted pilot signal.
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Abstract
A method for synchronizing a CDMA receiver to a transmitter when an adaptive antenna is utilized to receive transmitted data, wherein a receiving antenna system is adapted between a 360° reception angle pattern (i.e., an omni-directional pattern) and a fixed reception angle (i.e., a directional pattern) by permitting the receiver to identify a pilot signal having the largest magnitude. The receiver minimizes interference from other pilot signals by steering antenna pattern nulls toward other transmitters. As a result, the time required for the receiver to acquire a valid pilot signal is significantly reduced.
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Citations
16 Claims
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1. A method for synchronizing a receiver having an adaptive antenna to a transmitter, comprising the steps of:
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adapting the antenna to an omni-directional pattern; checking PN offsets of a transmitted pilot signal; storing PN offsets of the transmitted pilot signal which produce valid correlations of PN offsets; reloading each PN offset which produced the valid correlations of the PN offsets; steering the antenna to a directional pattern; and monitoring a correlation value of the PN offset which produced a valid correlation of a PN offset while adapting the antenna to the directional pattern to synchronize the receiver to a strongest transmitted pilot signal. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8)
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9. A method for synchronizing a receiver having an adaptive antenna to a transmitter, comprising:
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adapting the antenna to an omnidirectional receive pattern; detecting a PN offset of a pilot signal received by the antenna having an omnidirectional receive pattern; further adapting the antenna to a directional receive pattern; steering the directional receive pattern over a range of azimuth angles; and monitoring a received signal strength of the pilot signal as the directional receive pattern is steered in order to determine an optimal azimuth angle of the directional pattern for receiving the pilot signal at the detected PN offset. - View Dependent Claims (10, 11)
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12. A method for synchronizing a receiver having an adaptive antenna to a transmitter, comprising:
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adapting the antenna to an omnidirectional receive pattern; detecting a plurality of PN offsets of a multipath pilot signal by the antenna having an omnidirectional receive pattern; for each of the plurality of PN offsets, further adapting the antenna to a directional receive pattern; steering the directional receive pattern over a range of azimuth angles; and monitoring a received signal strength of the pilot signal as the directional receive pattern is steered in order to determine an optimal azimuth angle of the directional pattern for maximizing received signal strength of the pilot signal at that detected PN offset; and synchronizing the receiver to a selected one of the plurality of PN offsets and further adapting the antenna to a directional receive pattern at an azimuth angle that produces an optimal signal strength of the pilot signal.
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13. A system for synchronizing a receiver having an adaptive antenna to a transmitter, comprising at a receiver:
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a pilot searcher; an adaptive antenna comprising a plurality of antenna elements, each of the antenna elements controller by a phase shifter; the phase shifter adapting the plurality of antenna elements to an omnidirectional receive pattern; the pilot searcher detecting a PN offset of a pilot signal received by the adaptive antenna having an omnidirectional receive pattern; the phase shifter further adapting the plurality of antenna elements to a directional receive pattern; the phase shifter steering the directional receive pattern over a range of azimuth angles; and the pilot searcher monitoring a received signal strength of the pilot signal as the directional receive pattern is steered in order to determine an optimal azimuth angle of the directional pattern for receiving the pilot signal at the detected PN offset. - View Dependent Claims (14, 15)
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16. A system for synchronizing a receiver having an adaptive antenna to a transmitter, comprising at a receiver:
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a pilot searcher; an adaptive antenna comprising a plurality of antenna elements, each of the antenna elements controller by a phase shifter; the phase shifter adapting the plurality of antenna elements to an omnidirectional receive pattern; the pilot searcher detecting a plurality of PN offsets of a multipath pilot signal by the adaptive antenna having an omnidirectional receive pattern; for each of the plurality of PN offsets, the phase shifter further adapting the plurality of antenna elements to a directional receive pattern; the phase shifter steering the directional receive pattern over a range of azimuth angles; and the pilot searcher monitoring a received signal strength of the pilot signal as the directional receive pattern is steered in order to determine an optimal azimuth angle of the directional pattern for maximizing received signal strength of the pilot signal at that detected PN offset; and the receiver synchronizing to a selected one of the plurality of PN offsets and the phase shifter further adapting the antenna to a directional receive pattern at an azimuth angle that produces an optimal signal strength of the pilot signal.
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Specification