METHOD FOR CONTROLLING ARRAY ANTENNA EQUIPPED WITH A PLURALITY OF ANTENNA ELEMENTS, METHOD FOR CALCULATING SIGNAL TO NOISE RATIO OF RECEIVED SIGNAL, AND METHOD FOR ADAPTIVELY CONTROLLING RADIO RECEIVER
First Claim
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1. A method for controlling an array antenna, said array antenna comprising:
- a radiating element for receiving a radio signal;
at least one parasitic element provided apart from the radiating element by a predetermined distance; and
a variable reactance element connected to the parasitic element, thereby changing a directivity characteristic of said array antenna by changing a reactance value of said variable reactance element for operation of said variable reactance element as either one of a director and a reflector, wherein said method includes a step of calculating and setting the reactance value of said variable reactance element for directing a main beam of said array antenna in a direction of a desired wave and directing nulls in directions of interference waves on the basis of a received signal received by said radiating element so that a value of an objective function expressed by only the received signal becomes either one of the maximum and the minimum by using an iterative numerical solution of a nonlinear programming method.
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Abstract
Based on a received signal y(t) received by a radiating element of an array antenna including the single radiating element and a plurality of parasitic elements, an adaptive controller calculates and sets a reactance value of a variable reactance element for directing a main beam of the array antenna in a direction of a desired wave and directing nulls in directions of interference waves so that a value of an objective function expressed by only the received signal y(t) becomes either one of the maximum and the minimum by using an iterative numerical solution of a nonlinear programming method.
181 Citations
26 Claims
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1. A method for controlling an array antenna, said array antenna comprising:
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a radiating element for receiving a radio signal;
at least one parasitic element provided apart from the radiating element by a predetermined distance; and
a variable reactance element connected to the parasitic element, thereby changing a directivity characteristic of said array antenna by changing a reactance value of said variable reactance element for operation of said variable reactance element as either one of a director and a reflector, wherein said method includes a step of calculating and setting the reactance value of said variable reactance element for directing a main beam of said array antenna in a direction of a desired wave and directing nulls in directions of interference waves on the basis of a received signal received by said radiating element so that a value of an objective function expressed by only the received signal becomes either one of the maximum and the minimum by using an iterative numerical solution of a nonlinear programming method. - View Dependent Claims (2)
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3. A method for controlling an array antenna, said array antenna comprising:
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a radiating element for receiving a transmitted radio signal as a received signal;
at least one parasitic element provided apart from the radiating element by a predetermined distance; and
a variable reactance element connected to the parasitic element, thereby changing a directivity characteristic of said array antenna by changing a reactance value of said variable reactance element for operation of said variable reactance element as either one of a director and a reflector, wherein the transmitted radio signal is modulated by a modulation method including digital amplitude modulation, wherein a power ratio R is defined by a quotient obtained by dividing a larger power value of power values at two mutually different signal points of the radio signal by a smaller power value thereof, wherein the radio signal has predetermined discrete power ratios R1, R2, . . . , Rmax at a plurality of signal points of the digital amplitude modulation, and wherein said method includes the following steps of;
calculating the power ratio R for the power values at respective two signal points of mutually different combinations of the received signal for a predetermined time interval on the basis of the received signal received by the radiating element;
calculating as an objective function value, a minimum value of the absolute values of the values obtained by subtracting the discrete power ratios R1, R2, . . . , Rmax from respective calculated power ratios R, respectively; and
calculating and setting a reactance value of said variable reactance element for directing a main beam of said array antenna in a direction of a desired wave and directing nulls in directions of interference waves so that the objective function value becomes substantially either one of the minimum and the maximum. - View Dependent Claims (4, 5)
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6. A method for controlling an array antenna for receiving a transmitted radio signal, said array antenna comprising a plurality of P antenna elements aligned at predetermined intervals, said array antenna shifting phases of a plurality of P received signals received by said array antenna by predetermined quantities of phase shift using respective P phase shift means, respectively, combining phase-shifted received signals, and outputting combined received signal,
wherein the transmitted radio signal is modulated by a modulation method including digital amplitude modulation, wherein a power ratio R is defined by a quotient obtained by dividing a larger power value of power values at two mutually different signal points of the radio signal by a smaller power value thereof, wherein the radio signal has predetermined discrete power ratios R1, R2, . . . , Rmax at a plurality of signal points of the digital amplitude modulation, and wherein said method includes the following steps of: -
calculating the power ratio R for the power values at respective two signal points of mutually different combinations of the received signal for a predetermined time interval on the basis of the received signal received by the array antenna;
calculating as an objective function value, a minimum value of the absolute values of the values obtained by subtracting the discrete power ratios R1, R2, . . . , Rmax from respective calculated power ratios R, respectively; and
calculating and setting quantities of phase shift of said phase shift means for directing a main beam of said array antenna in a direction of a desired wave and directing nulls in directions of interference waves so that the objective function value becomes substantially either one of the minimum and the maximum. - View Dependent Claims (7, 8)
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9. A method for controlling an array antenna, said array antenna comprising:
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a radiating element for receiving a transmitted radio signal;
at least one parasitic element provided apart from the radiating element by a predetermined distance; and
a variable reactance element connected to the parasitic element, thereby changing a directivity characteristic of said array antenna by changing a reactance value of said variable reactance element for operation of said variable reactance element as either one of a director and a reflector, wherein the transmitted radio signal is modulated by an m-PSK modulation (where m is an integer equal to or larger than two); and
wherein said method includes a step of calculating and setting the reactance value of said variable reactance element for directing a main beam of said array antenna in a direction of a desired wave and directing nulls in directions of interference waves on the basis of a received signal received by said radiating element so that a value of a criterion function expressed by only the received signal raised to the m-th power becomes either one of the maximum and the minimum by using an iterative numerical solution of a nonlinear programming method. - View Dependent Claims (10)
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11. A method for controlling an array antenna comprising a plurality, of P antenna elements aligned at predetermined intervals, said array antenna shifting phases of a plurality of P received signals received by said array antenna by predetermined quantities of phase shift using respective P phase shift means, respectively, combining phase-shifted received signals, and outputting combined received signal,
wherein the transmitted radio signal is modulated by an m-PSK modulation (where m is an integer equal to or larger than two); - and
wherein said method includes a step of calculating and setting the quantities of phase shift of said respective P phase shift means for directing a main beam of said array antenna in a direction of a desired wave and directing nulls in directions of interference waves on the basis of a received signal received by said array antenna so that a value of a criterion function expressed by only the received signal raised to the m-th power becomes either one of the maximum and the minimum by using an iterative numerical solution of a nonlinear programming method. - View Dependent Claims (12)
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13. A method for adaptively controlling a radio receiver for receiving as a received signal, a radio signal modulated by m-PSK modulation (where m is an integer equal to or larger than two), said radio receiver comprising a signal processing means for processing the received signal,
wherein said method includes the following steps of: -
calculating a value of a criterion function obtained by dividing a square value of an absolute value of a mean value of the received signal raised to the m-th power value for a predetermined time interval by a mean value of the square value of the absolute value of the m-th power value of the received signal;
calculating a signal to noise ratio of the received signal by using an equation that expresses a relationship between the criterion function and the signal to noise ratio thereof on the basis of the calculated value of the criterion function; and
adaptively controlling said signal processing means so that the calculated signal to noise ratio becomes substantially the maximum. - View Dependent Claims (14, 15, 16, 17)
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18. A method for controlling an array antenna, said array antenna comprising:
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a radiating element for receiving a transmitted radio signal as a received signal;
at least one parasitic element provided apart from the radiating element by a predetermined distance; and
a variable reactance element connected to the parasitic element, thereby changing a directivity characteristic of said array antenna by changing a reactance value of said variable reactance element for operation of said variable reactance element as either one of a director and a reflector, wherein the transmitted radio signal is modulated by a m-PSK modulation (where m is an integer equal to or larger than two), wherein said method includes a step of calculating and setting a reactance value of a variable reactance element for directing a main beam of said array antenna in a direction of a desired wave and directing nulls in directions of an interference waves on the basis of a received signal received by the radiating element so that a value of a criterion function, which is a function obtained by dividing a (1/m)-th power value of an absolute value of a mean value of the received signal raised to the m-th power value for a predetermined time interval, by a (1/2)-th power value of the mean value of the absolute value of a square value of the received signal, becomes substantially the maximum, by using an iterative numerical solution of a nonlinear programming method.
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19. A method for controlling an array antenna comprising a plurality of P antenna elements aligned at predetermined intervals, said array antenna shifting phases of a plurality of P received signals received by said array antenna by predetermined quantities of phase shift using respective P phase shift means, respectively, combining phase-shifted received signals, and outputting combined received signal,
wherein the transmitted radio signal is modulated by an m-PSK modulation (where m is an integer equal to or larger than two); - and
wherein said method includes a step of calculating and setting the quantities of phase shift of the phase shift means for directing a main beam of said array antenna in a direction of a desired wave and directing nulls in directions of interference waves on the basis of the combined received signal so that a value of a criterion function, which is a function obtained by dividing a (1/m)-th power value of an absolute value of a mean value of the received signal raised to the m-th power value for a predetermined time interval by a (1/2)-th power value of the mean value of the absolute value of a square value of the received signal, becomes substantially the maximum by using an iterative numerical solution of a nonlinear programming method.
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20. A method for adaptively controlling a radio receiver for receiving as a received signal, a radio signal modulated by m-PSK modulation (where m is an integer equal to or larger than two), said radio receiver comprising a signal processing means for processing the received signal,
wherein said method includes the following steps of: -
calculating a value of a criterion function, which is a function obtained by dividing a (1/m)-th power value of an absolute value of a mean value of the received signal raised to the m-th power value for a predetermined time interval by a (1/2)-th power value of the mean value of the absolute value of a square value of the received signal;
calculating the signal to noise ratio of the received signal by using an equation, that expresses a relationship between the criterion function and the signal to noise ratio, on the basis of the calculated value of the criterion function; and
adaptively controlling said signal processing means so that the calculated signal to noise ratio becomes substantially the maximum. - View Dependent Claims (21, 22, 23, 24)
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25. A radio receiver apparatus comprising:
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a radio receiver for receiving a radio signal modulated by m-PSK modulation (where m is an integer equal to or greater than two); and
a controller for calculating a value of a criterion function obtained by dividing a square value of an absolute value of a mean value of the received radio signal raised to the m-th power value for a predetermined time interval by a mean value of the square value of the absolute value of the m-th power value of the received radio signal, and calculating a signal to noise ratio of the received radio signal by using an equation, that expresses a relationship between the criterion function and the signal to noise ratio thereof, on the basis of the calculated value of the criterion function.
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26. A radio receiver apparatus comprising:
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a radio receiver for receiving a radio signal modulated by m-PSK modulation (where m is an integer equal to or larger than two); and
a controller for calculating a value of a criterion function, which is a function obtained by dividing a (1/m)-th power value of an absolute value of a mean value of the received radio signal raised to the m-th power value for a predetermined time interval by a (1/2)-th power value of the mean value of the absolute value of a square value of the received radio signal, and calculating the signal to noise ratio of the received radio signal by using an equation, that expresses a relationship between the criterion function and the signal to noise ratio thereof, on the basis of the calculated value of the criterion function.
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Specification