Automatic gain control apparatus and method in an orthogonal frequency division multiple access sytem
First Claim
1. An automatic gain control (AGC) apparatus for maintaining received signal power in an orthogonal frequency division multiple access (OFDMA) system, the AGC apparatus comprising:
- a gain amplifier for amplifying the received signal;
a power measurer for measuring power of the received signal in units of sub-carriers;
a sub-carrier power accumulator for detecting at least one sub-carrier carrying a signal, and accumulating a power value of the at least one sub-carrier;
a sub-carrier average power measurer for estimating an average power value from the accumulated power value; and
a control means for comparing the estimated average power value with a reference power value, and for controlling a amplification gain of the gain amplifier according to the comparison result.
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Accused Products
Abstract
An automatic gain control (AGC) apparatus of a wireless mobile terminal, and method, in an orthogonal frequency division multiple access (OFDMA) system. A gain amplifier controls an amplification gain of received analog symbols. An analog-to-digital converter converts the received analog symbols into a digital signal. A fast Fourier transform (FFT) unit converts the digital signal into a frequency-domain signal. A power measurer measures power in the frequency domain in units of sub-carriers. A sub-carrier power accumulator detects a sub-carrier carrying a signal, and accumulates its power value. A sub-carrier average power measurer estimates an average power value transmitted per sub-carrier from the accumulated power value. A control means compares the estimated average power value with a reference power value, and generates a control signal used for controlling a gain of the gain amplifier according to the comparison result.
49 Citations
23 Claims
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1. An automatic gain control (AGC) apparatus for maintaining received signal power in an orthogonal frequency division multiple access (OFDMA) system, the AGC apparatus comprising:
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a gain amplifier for amplifying the received signal;
a power measurer for measuring power of the received signal in units of sub-carriers;
a sub-carrier power accumulator for detecting at least one sub-carrier carrying a signal, and accumulating a power value of the at least one sub-carrier;
a sub-carrier average power measurer for estimating an average power value from the accumulated power value; and
a control means for comparing the estimated average power value with a reference power value, and for controlling a amplification gain of the gain amplifier according to the comparison result. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13)
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14. An automatic gain control (AGC) method for maintaining received signal power uniformly in an orthogonal frequency division multiple access (OFDMA) system, the method comprising the steps of:
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measuring power of the received signal in units of sub-carriers;
detecting at least one sub-carrier carrying a signal among the measured sub-carriers;
estimating an average power value from the at least one power of the detected subcarrier; and
controlling a gain of a gain amplifier according to the average power wherein the gain amplifier controls an amplification gain of the received signal. - View Dependent Claims (15, 16, 17, 18, 19, 20, 21, 22, 23)
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Specification