Method and apparatus for canceling neighbor cell interference signals in an orthogonal frequency division multiple access system
First Claim
1. A method for canceling a neighbor cell interference signal upon receiving a signal transmitted from a serving base station (BS) in a receiver of an Orthogonal Frequency Division Multiple Access (OFDMA) system, the method comprising:
- detecting interference signals from signals received from at least one of a plurality of neighbor BSs and a serving BS;
measuring strength of the detected interference signals, and determining whether the measured strength is higher than a threshold value;
reordering in an order a list of neighbor BSs satisfying the determination result;
selecting and detecting interference signals in the order of the reordered neighbor BSs;
calculating and normalizing an interference/noise variance for the detected interference signal;
decoding and regenerating the normalized interference signal; and
subtracting the regenerated interference signal from the received signal.
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Abstract
A method and apparatus are provided where a neighbor cell interference signal is canceled upon receiving a signal transmitted from a serving base station (BS) in a receiver of an Orthogonal Frequency Division Multiple Access (OFDMA) system. The interference signals are detected from signals received from neighbor BSs and a serving BS. The strength of the detected interference signals is measures, and a determination is made whether the measured strength is higher than a threshold value. A list of neighbor BSs satisfying the determination result is reordered, and interference signals in order of the reordered neighbor BSs are selected and detected. An interference/noise variance for the detected interference signal is calculated and normalized. The normalized interference signal is decoded and regenerated, and the regenerated interference signal is subtracted from the received signal.
77 Citations
27 Claims
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1. A method for canceling a neighbor cell interference signal upon receiving a signal transmitted from a serving base station (BS) in a receiver of an Orthogonal Frequency Division Multiple Access (OFDMA) system, the method comprising:
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detecting interference signals from signals received from at least one of a plurality of neighbor BSs and a serving BS;
measuring strength of the detected interference signals, and determining whether the measured strength is higher than a threshold value;
reordering in an order a list of neighbor BSs satisfying the determination result;
selecting and detecting interference signals in the order of the reordered neighbor BSs;
calculating and normalizing an interference/noise variance for the detected interference signal;
decoding and regenerating the normalized interference signal; and
subtracting the regenerated interference signal from the received signal. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8)
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9. A method for canceling a neighbor cell interference signal upon receiving a signal transmitted from a serving base station (BS) in a receiver of an Orthogonal Frequency Division Multiple Access (OFDMA) system, the method comprising:
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detecting interference signals from signals received from at least one of a plurality of neighbor BSs and a serving BS;
measuring strength of the detected interference signals, and determining whether the measured strength is higher than a threshold value;
reordering in an order of a list of neighbor BSs satisfying the determination result;
selecting and detecting interference signals in the order of the reordered neighbor BSs;
calculating and normalizing an interference/noise variance for the detected interference signal;
slicing and regenerating the normalized interference signal; and
subtracting the regenerated interference signal from the received signal. - View Dependent Claims (10, 11, 12, 13, 14, 15)
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16. An apparatus for canceling a neighbor cell interference signal in a receiver for receiving a signal transmitted from a serving base station (BS) in an Orthogonal Frequency Division Multiple Access (OFDMA) system, the apparatus comprising:
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a controller for performing a control operation of measuring strength of signals received from a serving BS and at least one of a plurality of neighbor BSs, and regenerating an interference signal received from the at least one of the plurality of the neighbor BSs if a difference between the signal strengths satisfies a threshold value, and performing a control operation of outputting a variance of an interference/noise signal among the signals received from the serving BS and the neighbor BSs;
an interference canceller for regenerating the interference signal under the control of the controller;
an interference/noise variance estimator for outputting interference/noise variance information under the control of the controller;
a normalizer for normalizing an input metric based on the information received from the interference/noise variance estimator; and
a subtractor for subtracting the regenerated interference signal from the signal received from the serving BS. - View Dependent Claims (17, 18, 19, 20)
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21. An apparatus for canceling a neighbor cell interference signal in a receiver for receiving a signal transmitted from a serving base station (BS) in an Orthogonal Frequency Division Multiple Access (OFDMA) system, the apparatus comprising:
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a controller for performing a control operation of measuring strength of signals received from a serving BS and at least one of a plurality of neighbor BSs, and regenerating an interference signal received from the at least one of the plurality of the neighbor BSs if a difference between the signal strengths satisfies a threshold value, and performing a control operation of outputting a variance of an interference/noise signal among the signals received from the serving BS and the neighbor BSs;
an interference canceller for regenerating the interference signal under the control of the controller;
an interference/noise variance estimator for outputting interference/noise variance information of the received signal from which the interference signal is canceled, under the control of the controller;
a normalizer for normalizing an input metric based on the information received from the interference/noise variance estimator; and
a subtractor for subtracting the regenerated interference signal from the signal received from the serving BS. - View Dependent Claims (22, 23, 24, 25)
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26. A method for canceling a neighbor cell interference signal upon receiving a signal transmitted from a serving base station (BS) in an Orthogonal Frequency Division Multiple Access (OFDMA) system, the method comprising:
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scanning neighbor BSs from which interference signals are received;
measuring a Carrier to Interference plus Noise Ratio (CINR) of the interference signals received from the neighbor BSs;
determining the highest CINR among the measured CINRs which are higher than a threshold value;
regenerating an interference signal having the highest CINR; and
subtracting the regenerated interference signal from the received signal.
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27. An apparatus for canceling a neighbor cell interference signal in a receiver for receiving a signal transmitted from a serving base station (BS) in an Orthogonal Frequency Division Multiple Access (OFDMA) system, the apparatus comprising:
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a controller for scanning at least one of a plurality of neighbor BSs from which interference signals are received, measuring a Carrier to Interference plus Noise Ratio (CINR) of the interference signals received from the at least one of the neighbor BSs, and determining the highest CINR among the measured CINRs which are higher than a threshold value;
an interference canceller for regenerating an interference signal having the highest CINR under the control of the controller; and
a subtractor for subtracting the regenerated interference signal from the received signal.
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Specification