Use of smart antenna in beam formation circuit
First Claim
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1. A receiver apparatus provided with a smart antenna capable of adjusting a directivity of the smart antenna by making use of a plurality of antenna elements, said receiver apparatus comprising:
- a plurality of Fourier transformation sections which are connected to said plurality of antenna elements and configured to output signals carried on sub-carriers orthogonal to each other from signals received by each of said antenna elements;
a plurality of parallel-to-serial conversion sections which are connected respectively to said Fourier transformation sections and configured to perform parallel-to-serial conversion of the signals carried on said sub-carriers as Fourier transformed in a time division manner;
a pilot signal extraction unit which intermittently extracts signals carried on pilot sub-carriers having predetermined center frequencies from the output signals of said parallel-to-serial conversion sections;
an antenna weight calculation unit which is connected to said Fourier transformation sections and said pilot signal extraction unit and configured to calculate an antenna weight of each antenna elements corresponding to each of sub-carrier groups by the use of the signals carried on said pilot sub-carriers as extracted by said pilot signal extraction unit, each sub-carrier group including a plurality of the sub-carriers whose center frequencies are located in a vicinity of a center frequency of one pilot sub-carrier;
a plurality of weighting units which are connected to said plurality of parallel-to-serial conversion sections and said antenna weight calculation unit and configured to multiply the output signals of said plurality of parallel-to-serial conversion sections with said antenna weights as calculated by said antenna weight calculation unit for each of the sub-carrier groups;
an adder circuit which is connected to said weighting units and configured to add together the signals of said sub-carrier groups as weighted with said antenna weights for each of said antenna elements; and
a timing controlling unit which is connected to said pilot signal extraction unit and said antenna weight calculation unit and configured to supply timing signals to said pilot signal extraction unit and said antenna weight calculation unit in order that said antenna weight of each antenna elements is switched for each said sub-carrier group in a cyclic manner.
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Abstract
A beam formation circuit and an apparatus and a method of receiving radio frequency signals making use of a smart antenna are described in which the amount of computation tasks required for the weight calculation is significantly reduced. In realizing the directivity of the smart antenna, the output signals corresponding to a plurality of sub-carriers are weighted with a common antenna weight for each of the antenna elements.
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Citations
5 Claims
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1. A receiver apparatus provided with a smart antenna capable of adjusting a directivity of the smart antenna by making use of a plurality of antenna elements, said receiver apparatus comprising:
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a plurality of Fourier transformation sections which are connected to said plurality of antenna elements and configured to output signals carried on sub-carriers orthogonal to each other from signals received by each of said antenna elements; a plurality of parallel-to-serial conversion sections which are connected respectively to said Fourier transformation sections and configured to perform parallel-to-serial conversion of the signals carried on said sub-carriers as Fourier transformed in a time division manner; a pilot signal extraction unit which intermittently extracts signals carried on pilot sub-carriers having predetermined center frequencies from the output signals of said parallel-to-serial conversion sections; an antenna weight calculation unit which is connected to said Fourier transformation sections and said pilot signal extraction unit and configured to calculate an antenna weight of each antenna elements corresponding to each of sub-carrier groups by the use of the signals carried on said pilot sub-carriers as extracted by said pilot signal extraction unit, each sub-carrier group including a plurality of the sub-carriers whose center frequencies are located in a vicinity of a center frequency of one pilot sub-carrier; a plurality of weighting units which are connected to said plurality of parallel-to-serial conversion sections and said antenna weight calculation unit and configured to multiply the output signals of said plurality of parallel-to-serial conversion sections with said antenna weights as calculated by said antenna weight calculation unit for each of the sub-carrier groups; an adder circuit which is connected to said weighting units and configured to add together the signals of said sub-carrier groups as weighted with said antenna weights for each of said antenna elements; and a timing controlling unit which is connected to said pilot signal extraction unit and said antenna weight calculation unit and configured to supply timing signals to said pilot signal extraction unit and said antenna weight calculation unit in order that said antenna weight of each antenna elements is switched for each said sub-carrier group in a cyclic manner. - View Dependent Claims (2, 3, 4, 5)
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Specification