Directional antenna apparatus and mobile communication system using the same

• US 20010052875A1
• Filed: 04/12/2001
• Published: 12/20/2001
• Est. Priority Date: 04/17/2000
• Status: Active Grant

• Current Assignee: Ryuji Kohno, Toshiba Tec Corporation (Toshiba Corporation)
• Original Assignee: Toshiba Tec Corporation (Toshiba Corporation)
• Inventors: Sugiyama, Tomonori, Kohno, Ryuji
• Granted Patent: US 6,473,055 B2
• Time in Patent Office: Days
• US Class Current: 342/417
• CPC Class Codes: G01S 3/325 Automatic tracking systems

Abstract

The directional antenna apparatus of a base station, after sensing the direction of an undesired wave, calculates the optimum amplitude weighting coefficients and optimum phase weighting coefficients for a plurality of directions between the move starting point and move end point of a mobile station and creates a reference table. Then, when receiving a request for communication from the mobile station, the directional antenna apparatus reads weighting coefficients from the reference table, sets them in each antenna element, and points the directivity toward the mobile station, and starts communication. Then, calculating the time when the mobile station arrives at the position corresponding to each direction from the destination of the mobile station and its moving speed, and reads one by one the optimum amplitude and phase weighting coefficients from the reference table, and sets them in each antenna element, and communicates with the mobile station, while tracking the mobile station.

Claims

1. A directional antenna apparatus comprising:

a plurality of antenna elements which transmit and receive a radio signal to and from a mobile station;

weighting means for weighting the amplitude and phase of the transmission or reception signal of each of the individual antenna elements;

adding means for adding the reception signals from said individual antenna elements weighted by the weighting means and outputting the resulting signal to a reception unit;

dividing means for dividing a transmission signal from a transmission unit to said weighting means corresponds to said individual antenna elements;

storage means for storing weighting coefficients suitable for communication with the mobile station for each of a plurality of moving positions of said mobile station; and

control means for setting the weighting coefficients stored in said storage means in said weighting means each timing said mobile station moves to each of the moving positions.

2. The directional antenna apparatus according to

claim 1

, wherein said mobile station is a portable wireless terminal.

3. The directional antenna apparatus according to

claim 1

, wherein said mobile station is a wireless tag.

4. A directional antenna apparatus comprising:

a plurality of antenna elements which transmit and receive a radio signal to and from a mobile station;

weighting means for weighting the amplitude and phase of the transmission or reception signal of each of the individual antenna elements;

adding means for adding the reception signals from said individual antenna elements weighted by the weighting means and outputting the resulting signal to a reception unit;

dividing means for dividing a transmission signal from a transmission unit to said weighting means corresponds to the individual antenna elements;

storage means for storing weighting coefficients suitable for communication with the mobile station for each of a plurality of directions set between the direction of the move starting position and move end position of said mobile station;

timing generating means for determining the timing with which the weighting coefficients suitable for the direction of the mobile station are read from said storage means sequentially as the mobile station moves from the move starting position to the move end position; and

control means for reading the weighting coefficients for the corresponding direction of said mobile station from said storage means with the timing determined by the timing generating means and setting the weighting coefficients in said weighting means.

5. The directional antenna apparatus according to

claim 4

, wherein said timing generating means calculates, from the moving speed of the mobile station moving from the move starting position to move end position, the time when the mobile station arrives at each of a plurality of directions set between the direction of the move starting position and the direction of the move end position, and determining the timing.

6. The directional antenna apparatus according to

claim 4

, wherein said timing generating means calculates from the moving speed of the mobile station the time required for the mobile station to move from the move starting position to the move end position, sets a plurality of times within the calculated time, and determines the set times to be the timing of reading weighting coefficients from the storage means.

7. A mobile communication system using a directional antenna apparatus according to

claim 4

, comprising:

a gate through which said mobile station passes; and

sensor means which is provided at the end portions of the gate and which senses the approach of said mobile station to said gate and informs a base station of the approach, wherein

said control means, in response to the notice signal from said sensor means, reads the weighting coefficients for the corresponding direction of said mobile station from said storage means with the timing determined by the timing generating means and sets the weighting coefficients in said weighting means.

8. A mobile communication system using a directional antenna apparatus according to

claim 4

, comprising:

a plurality of sensor means for sensing said mobile station at different positions and informing a base station of the result of the sensing;

wherein

said storage means stores weighting coefficients suitable for communication with said mobile station for each of the positions in which said individual sensor means are placed; and

said control means, in response to the notice from each of said individual sensor means, reads the weighting coefficients corresponding to the position in which the corresponding sensor means is placed from said storage means and sets the weighting coefficients in said weighting means.

9. A base station used in a mobile communication system comprising:

a plurality of antenna elements which transmit and receive a radio signal to and from a mobile station;

weighting means for weighting the amplitude and phase of the transmission or reception signal of each of the individual antenna elements;

adding means for adding the reception signals of said individual antenna elements weighted by the weighting means and outputting the resulting signal to a reception unit;

dividing means for dividing a transmission signal from a transmission unit to said weighting means corresponds to the individual antenna elements;

storage means for storing weighting coefficients suitable for communication with the mobile station for each of a plurality of directions set between the direction of the move starting position and move end position of said mobile station;

timing generating means for determining the timing with which the weighting coefficients suitable for the direction of the mobile station are read from said storage means sequentially as the mobile station moves from the move starting position to the move end position; and

control means for reading the weighting coefficients for the corresponding direction of said mobile station from said storage means with the timing determined by the timing generating means and setting the weighting coefficients in said weighting means.