Communication system, communications device, and antenna element arrangement method
A communication system includes a transmitter that includes N t transmission antenna elements that are arranged in a row, and transmits a signal by a space division multiplexing scheme, and a receiver that includes N r reception antenna elements that are arranged in a row, and receives a signal by the space division multiplexing scheme, wherein a distance between first and second transmission antenna elements from an end position is different from a distance between the second and third transmission antenna elements from the end position, the N t transmission antenna elements including the first, second and third antenna elements, and a distance between first and second reception antenna elements from an end position is different from a distance between the second and third transmission antenna elements from the end position, the N r transmission antenna elements including the first, second and third antenna elements.
1. A communication system comprising:
a transmitter configured to include a plurality of transmission antenna elements that are arranged in a row, and to transmit a signal by a space division multiplexing scheme; and
a receiver configured to include a plurality of reception antenna elements that are arranged in a row, and to receive a signal by the space division multiplexing scheme, wherein:
the plurality of transmission antenna elements includes a first transmission antenna element, a second transmission antenna element, and a third transmission antenna element;
the first transmission antenna element is a terminal transmission antenna element of the plurality of transmission antenna elements, the second transmission antenna element is located next to the first transmission antenna element, and the third transmission antenna element is located next to the second transmission antenna element;
a distance between the first transmission antenna element and the second transmission antenna element is different from a distance between the second transmission antenna element and the third transmission antenna element;
the plurality of reception antenna elements include a first reception antenna element, a second reception antenna element and a third reception antenna element;
the first reception antenna element is a terminal reception transmission antenna element of the plurality of reception antenna elements, the second reception antenna element is located next to the first reception antenna element, and the third reception antenna element is located next to the second reception antenna element; and
a distance between the first reception antenna element and the second reception antenna element is different from a distance between the second reception antenna element and the third reception antenna element.
2. The communication system according to claim 1 , wherein:
the distance between the first transmission antenna element and the second transmission antenna element is (1/2+α 2 )d t and the distance between the second transmission antenna element and the third transmission antenna element is (3/2+α 3 )d t , where the d t is a reference distance that is determined from a number of the transmission antenna elements N t that are included in the plurality of transmission antenna elements, a wavelength λ of a signal to be transmitted, and a range R between the transmission antenna elements and the reception antenna elements,
the distance between the first reception antenna element and the second reception antenna element is (1/2+β 2 )d r and the distance between the second reception antenna element and the third reception antenna element is (3/2+β 3 )d r , where the d r is a reference distance that is determined from a number of the reception antenna elements N r that are included in the plurality of transmission antenna elements, the wavelength λ, and the range R, and
the α 2 , α 3 , β 2, and β 3 are values within ±0.15.
3. The communication system according to claim 1 , wherein the transmitter and the receiver are configured to perform transmission and reception of a signal in a line-of-sight environment by the space division multiplexing scheme.
4. The communication system according to claim 2 , wherein:
coordinates of the plurality of transmission antenna elements that are arranged in a row are respectively represented as 0, (1/2+α 2 )d t , (2+α 3 )d t , . . . , (N t −2+α Nt−1 )d t , and (N t −1)d t ,
coordinates of the plurality of reception antenna elements that are arranged in a row are respectively represented as 0, (1/2+β 2 )d r , (2+β 3 )d r , . . . , (N r −2+β Nr−1 )d r , and (N r −1)d r , and
α i (i=2, . . . , and N t −1) and β j (j=2, . . . , and N r −1) are values within ±0.15.
5. The communication system according to claim 2 , wherein:
coordinates of the plurality of transmission antenna elements that are arranged in a row are respectively represented as 0, (1/2+α 2 )d t , (2+α 3 )d t , . . . , (N t −2+α Nt−1 )d t , and (N t −1)d t ,
coordinates of the plurality of reception antenna elements that are arranged in a row are respectively represented as 0, (1+β 2 )d r , (2+β 3 )d r , . . . , (N r −2+1/2+β Nr−1 )d r , and (N r −1)d r , and
α i (i=2, . . . , and N t −1) and β j (j=2, . . . , and N r −1) are values within ±0.15.
6. The communication system according to claim 2 , wherein:
coordinates of the plurality of transmission antenna elements that are arranged in a row are respectively represented as 0, (1+α 2 )d t , (2+α 3 )d t , . . . , (N t −2+1/2+α Nt−1 )d t , and (N t −1)d t ,
coordinates of the plurality of reception antenna elements that are arranged in a row are respectively represented as 0, (1+β 2 )d r , (2+β 3 )d r , . . . , (N r −2+1/2+β Nr−1 )d r , and (N r −1)d r , and
α i (i=2, . . . , and N t −1) and β j (j=2, . . . , and N r −1) are values within ±0.15.
7. The communication system according to claim 2 , wherein:
coordinates of the plurality of transmission antenna elements that are arranged in a row are respectively represented as 0, (1+α 2 )d t , (2+α 3 )d t , . . . , (N t −2+1/2+α Nt−1 )d t , and (N t −1)d t ,
coordinates of the plurality of reception antenna elements that are arranged in a row are respectively represented as 0, (1/2+β 2 )d r , (2+β 3 )d r , . . . , (N r −2+β Nr−1 )d r , and (N r −1)d r , and
α i (i=2, . . . , and N t −1) and β j (j=2, . . . , and N r −1) are values within ±0.15.
8. The communication system according to claim 1 , wherein the transmitter and the receiver are fixed base stations.
9. A communication device configured to perform one of signal transmission and signal reception by a space division multiplexing scheme, the communication device comprising:
a plurality of antenna elements that are arranged in a row, wherein:
the plurality of antenna elements include a first transmission antenna element, a second transmission antenna element, and a third transmission antenna element;
the first antenna element is a terminal transmission antenna element of the plurality of antenna elements, the second antenna element is located next to the first antenna element, and the third antenna element is located next to the second antenna element; and
a distance between the first antenna element and the second antenna element is different from a distance between the second antenna element and the third antenna element.
10. An antenna element arrangement method that is to be executed by a device to determine an arrangement of a plurality of transmission antenna elements that are arranged in a row in a transmitter configured to transmit a signal by a space division multiplexing scheme and a plurality of reception antenna elements that are arranged in a row in a receiver configured to receive a signal by the space division multiplexing scheme, a number of the transmission antenna elements included in the plurality of transmission antenna elements being equal to a number of the reception antenna elements included in the plurality of reception antenna elements, the antenna element arrangement method comprising:
calculating a reference distance d i based on the number of the transmission antenna elements or the number of the reception antenna elements, a wavelength λ of a signal, and a distance R between the plurality of transmission antenna elements in the transmitter and the plurality of reception antenna elements in the receiver;
arranging, on the transmitter, the plurality of transmission antenna elements in a row at equal intervals by the reference distance d i , the plurality of transmission antenna elements including a first transmission antenna element, a second transmission antenna element, and a third transmission antenna element, the first transmission antenna element being a terminal transmission antenna element of the plurality of transmission antenna elements, the second transmission antenna element being located next to the first transmission antenna element, and the third transmission antenna element being located next to the second transmission antenna element;
shifting a position of the second transmission antenna element so that a distance between the first transmission antenna element and the second transmission antenna element is different from a distance between the second transmission antenna element and the third transmission antenna element;
arranging, on the receiver, the plurality of reception antenna elements in a row at equal intervals by the reference distance d i , the plurality of reception antenna elements including a first reception antenna element, a second reception antenna element, and a third reception antenna element, the first reception antenna element being a terminal reception antenna element of the plurality of reception antenna elements, the second reception antenna element being located next to the first reception antenna element, and the third reception antenna element being located next to the second reception antenna element;
shifting a position of the second reception antenna element such that a distance between the first reception antenna element and the second reception antenna element is different from a distance between the second reception antenna element and the third reception antenna element.