Interference detection for spread spectrum systems
First Claim
1. A method for detecting interference in a spread spectrum system, comprising the steps of:
- (a) generating received signal strength indication (RSSI) samples at a plurality of frequencies across a frequency range of the spread spectrum system;
(b) generating statistics based on the RSSI samples;
(c) analyzing the statistics; and
(d) determining whether interference is present in the frequency range by determining whether the interference corresponds to (1) narrow-band interference occurring over a narrow-band frequency range or (2) wide-band interference over a wide-band frequency range, wherein;
sizes of the narrow-band and wide-band frequency ranges are both smaller than the frequency range of the spread spectrum system; and
the size of the narrow-band frequency range is smaller than the size of the wide-band frequency range.
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Abstract
In spread spectrum systems, such as CDMA-based systems, the presence of even narrow-band interference, such as that caused by jamming at a particular frequency, can adversely affect all of the current users in the system. According to the present invention, interference is detected and characterized by accumulating statistics for each energy spectrum in the system (e.g., for both the forward link band and the reverse link band in a telecommunication system). In particular, since a spread spectrum is ideally flat across the entire frequency band, narrow-band interference can be detected based on a significant deviation between the signal strength at any one frequency and the average signal level across the entire band. Similarly, wide-band interference can be detected based on the variance level over the entire frequency band. In a preferred embodiment, a pair of receivers are designed to perform background interference-detection processing for both the forward and reverse link.
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Citations
21 Claims
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1. A method for detecting interference in a spread spectrum system, comprising the steps of:
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(a) generating received signal strength indication (RSSI) samples at a plurality of frequencies across a frequency range of the spread spectrum system; (b) generating statistics based on the RSSI samples; (c) analyzing the statistics; and (d) determining whether interference is present in the frequency range by determining whether the interference corresponds to (1) narrow-band interference occurring over a narrow-band frequency range or (2) wide-band interference over a wide-band frequency range, wherein; sizes of the narrow-band and wide-band frequency ranges are both smaller than the frequency range of the spread spectrum system; and the size of the narrow-band frequency range is smaller than the size of the wide-band frequency range. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 20)
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10. An apparatus for detecting interference in a spread spectrum system, comprising:
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(a) means for generating received signal strength indication (RSSI) samples across a frequency range of the spread spectrum system; (b) means for generating statistics based on the RSSI samples; (c) means for analyzing the statistics; and (d) means for determining whether interference is present in the frequency range by determining whether the interference corresponds to (1) narrow-band interference occurring over a narrow-band frequency range or (2) wide-band interference over a wide-band frequency range, wherein; sizes of the narrow-band and wide-band frequency ranges are both smaller than the frequency range of the spread spectrum system; and the size of the narrow-band frequency range is smaller than the size of the wide-band frequency range.
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11. A receiver for detecting interference in a spread spectrum system, wherein the receiver comprises:
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a first processing block configured to generate received signal strength indication (RSSI) samples at a plurality of frequencies across a frequency range of the spread spectrum system and to generate statistics based on the RSSI samples; and one or more additional processing blocks configured to analyze the statistics and to determine whether interference is present in the frequency range by determining whether the interference corresponds to (1) narrow-band interference occurring over a narrow-band band frequency range or (2) wide-band interference over a wide-band frequency range, wherein; sizes of the narrow-band and wide-band frequency ranges are both smaller than the frequency range of the spread spectrum system; and the size of the narrow-band frequency range is smaller than the size of the wide-band frequency range. - View Dependent Claims (12, 13, 14, 15, 16, 17, 18, 19, 21)
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Specification