Radio communication system

• US 6,400,955 B1
• Filed: 01/25/1999
• Issued: 06/04/2002
• Est. Priority Date: 06/01/1998
• Status: Expired due to Fees

• Current Assignee: Mitsubishi Denki Kabushiki Kaisha (Mitsubishi Electric Corporation)
• Original Assignee: Mitsubishi Denki Kabushiki Kaisha (Mitsubishi Electric Corporation)
• Inventors: Moritani, Yoichi, Mikuni, Yuko, Kawabata, Takashi
• Primary Examiner(s): Urban, Edward F.
• Assistant Examiner(s): ZEWDU, MELESS NMN
• Application Number:
  US09/236,392
• Time in Patent Office: 1,226 Days
• Field of Search: 455/446, 455/449, 455/450, 455/452, 455/62, 455/63, 455/561, 455/562, 370/337, 370/339
• US Class Current: 455/450
• CPC Class Codes: H04W 16/02 Resource partitioning among network components, e.g. reuse partitioning
• CPC Class Codes: H04W 16/12 Fixed resource partitioning
• CPC Class Codes: H04W 16/24 Cell structures
• CPC Class Codes: H04W 16/28 using beam steering
• CPC Class Codes: H04W 88/08 Access point devices

Abstract

In a radio communication system repeatedly using the same frequency, each base station and terminal station have directional antennas respectively, and a base station has direction-determining patterns for setting a direction of an antenna according to a timing, the adjacent base stations each using the same frequency use different direction-determining. patterns from each other, and remote base stations repeatedly use the same direction-determining patterns. The direction-determining pattern has a correlation between a timing obtained by equally dividing a frame for a communication line by a number of direction-determining patterns and each antenna direction, and a communication slot is allocated based on a timing decided according to the table to a communication line with a terminal station positioned at a particular direction.

Claims

1. A radio communication system with a directional antenna provided in each base station and a means for setting a direction of the antenna for each communication slot, said radio communication system repeatedly using radio waves at the same frequency;

where a plurality of direction-determining patterns are prepared in each base station;

a base station selects a first direction-determining pattern among the plurality of direction-determining patterns;

each base station adjacent to said base station selects a direction-determining pattern different from said first direction-determining pattern;

each remote base station repeatedly uses-said first direction-determining pattern, whereby the adjacent base stations avoid using the same antenna direction at the same time; and

a base station has a means for selecting a directivity segregation number as a natural number smaller than the number of directivity segregation, each of base stations adjacent to the base station has a means for selecting a directivity segregation number different from the first directivity segregation number, and each of remote base stations can repeatedly select the first directivity segregation number.

2. A radio communication system according to claim 1;

wherein each of said direction-determining patterns has a correlation between a period obtained by equally dividing a frame for a communication line by a number of direction-determining patterns and each antenna direction, and a base station has a means for dynamically selecting one among said direction-determining patterns as well as a means for determining an antenna directions used for communications with a terminal station and allocates a communication slot used for communications with a terminal station determined as one using a particular antenna direction from slots included in the period correlated by the direction-determining pattern.

3. A radio communication system according to claim 1;

wherein each of said direction-determining patterns has a correlation between a timing obtained by equally dividing a frame for a communication line by a number of direction-determining patterns and each antenna direction, and a base station has a means for dynamically selecting one among said direction-determining patterns as well as a means for determining an antenna direction used for communications with a terminal station and allocates a communication slot used for communications with a terminal station determined as one using a particular antenna direction from slots each having a timing adjacent to said timing correlated by the direction-determining pattern.

4. A radio communication system according to claim 1;

wherein said base station has a plurality of broadcasting channels for broadcasting common information to terminal stations, and said base station avoids, by dynamically selecting a broadcasting channel different from those of adjacent base stations, interference from the adjacent base stations to the broadcasting channel of said base station, and by setting a number of broadcasting channels to be the same as the number of direction-determining patterns, said base station dynamically selects one among the direction-determining patterns correlated to the dynamically selected broadcasting channel.

5. A radio communication system with a directional antenna provided in each base station and a means for setting a direction of the antenna for each communication slot, said radio communication system repeatedly using radio waves at the same frequency;

wherein a number of directivity segregation is set to an integer more than 2, and a base station has a means for selecting a directivity segregation number as a natural number smaller than the number of directivity segregation, each of base stations adjacent to the base station has a means for selecting a directivity segregation number different from the first directivity segregation number, and each of remote base stations can repeatedly select the first directivity segregation number; and

a base station has, for the purpose of allocating a communication slot to a terminal station, a means for obtaining sector numbers as natural numbers into which an angle of a radio wave to a terminal station is classified;

a means for obtaining, by combining said sector number with the directivity segregation number of said base station, allocation-target slots different from each other; and

a means for allocating slots to terminal stations around each of the allocation-target slots.

6. A radio communication system according to claim 5;

wherein said base station has a plurality of broadcasting channels for broadcasting common information to terminal stations, and said base station avoids, by dynamically selecting a broadcasting channel different from those of adjacent base stations, interference from the adjacent base stations to the broadcasting channel of said base station, and by setting a number of broadcasting channels to be the same as the number of directivity segregation, said base station selects the directivity segregation number correlated to the dynamically selected broadcasting channel.

7. A radio communication system with a directional antenna provided in each base station and a means for setting a direction of the antenna for each communication slot, said radio communication system repeatedly using radio waves at the same frequency;

wherein a number of directivity segregation is set to an integer more than 2, and said base station has a means for selecting a directivity segregation number as a natural number smaller than the number of directivity segregation, each of base stations adjacent to the base station has a means for selecting a directivity segregation number different from the first directivity segregation number, and each of remote base stations can repeatedly select the first directivity segregation number; and

a base station has, for the purpose of allocating a communication slot to a terminal station, a means for obtaining allocation-target slots different from each other by combining an angle of a radio wave to a terminal station with a directivity segregation number of the base station; and

a means for allocating slots to terminal stations around each of the allocation-target slots.

8. A radio communication system according to claim 7;

wherein said base station has a plurality of broadcasting channels for broadcasting common information to terminal stations, and said base station avoids, by dynamically selecting a broadcasting channel different from those of adjacent base stations, interference from the adjacent base stations to the broadcasting channel of said base station, and by setting a number of broadcasting channels to be the same as the number of directivity segregation, said base station selects the directivity segregation number correlated to the dynamically selected broadcasting channel.

9. In a radio communication system having a directional antenna in each of a plurality of base stations, the each of the plurality of base stations communicating with a terminal station over a communication slot, a method for setting a direction of the directional antenna for the communication slot, the radio communication system repeatedly using radio waves of the same frequency, the method comprising:

selecting a first direction determining pattern from a plurality of direction determining patterns in a first base station, the plurality of direction determining patterns being prepared in each of the plurality of base stations;

selecting a different direction determining pattern from the first direction determining pattern in each of the plurality of base stations adjacent to the first base station;

selecting the first direction determining pattern for use in each non-adjacent remote base station of the plurality of base stations wherein the adjacent base stations avoid using the same antenna direction at the same time; and

a base station has a means for selecting a directivity segregation number as a natural number smaller than the number of directivity segregation, each of base stations adjacent to the base station has a means for selecting a directivity segregation number different from the first directivity segregation number, and each of remote base stations can repeatedly select the first directivity segregation number.

10. The method according to claim 9, further including the steps of:

establishing a correlation between a period obtained by equaling dividing a communication frame by a number of the plurality of direction determining patterns and the direction of the directional antenna;

selecting one of the plurality of direction determining patterns;

determining an antenna direction used for communication with a terminal station; and

allocating a communication slot for communicating with the terminal station from a plurality of communication slots included in the period, which correlates to the determined antenna direction.

11. The method according to claim 9, further including the steps of:

establishing a correlation between a timing obtained by equaling dividing a communication frame by a number of the plurality of direction determining patterns and the direction of the directional antenna;

selecting one of the plurality of direction determining patterns;

determining an antenna direction used for communication with a terminal station; and

allocating a communication slot for communicating with the terminal station from a plurality of communication slots included in the timing, which correlates to the determined antenna direction.

12. The method according to claim 9, further including the steps of:

broadcasting common information to terminal stations over a plurality of broadcasting channels associated with each of the plurality of base stations;

selecting a broadcasting channel different from one or more broadcasting channels associated with the adjacent base stations to avoid interference;

setting a number of broadcasting channels to be the same as the number of direction determining patterns; and

selecting one of the plurality of direction determining patterns correlated to the selected broadcasting channel.

13. In a radio communication system having a directional antenna in each of a plurality of base stations, the each of the plurality of base stations communicating with a terminal station over a communication slot, a method for setting a direction of the directional antenna for the communication slot, the radio communication system repeatedly using radio waves of the same frequency, the method comprising:

setting, in the radio communication system, a directivity segregation to an integer more than two;

selecting, in a first base station, a first directivity segregation number as a natural number smaller than the number of directivity segregation;

selecting in adjacent base stations, a second directivity segregation number different from the first directivity segregation number; and

repeatedly selecting in the remote base stations the first directivity segregation number, wherein one or more of the base stations is further configured to;

obtain sector numbers as natural numbers into which an angle of a radio wave to a terminal station is classified;

obtaining allocation target slots different from each other by combining the obtained sector numbers with the directivity segregation number of the base station; and

allocating slots to terminal stations around each of the allocation target slots.

14. The method according to claim 13, further including the steps of:

broadcasting common information to terminal stations over a plurality of broadcasting channel;

selecting a broadcasting channel different from those of adjacent base stations to avoid interference from adjacent base stations;

setting a number of broadcasting channels to be the same as the number of directivity segregation;

selecting the directivity segregation number correlated to the selected broadcasting channel.

15. In a radio communication system having a directional antenna in each of a plurality of base stations, the each of the plurality of base stations communicating with a terminal station over a communication slot, a method for setting a direction of the directional antenna for the communication slot, the radio communication system repeatedly using radio waves of the same frequency, the method comprising:

setting, in the radio communication system, a directivity segregation to an integer more than two;

selecting, in a first base station, a first directivity segregation number as a natural number smaller than the number of directivity segregation;

selecting, in adjacent base stations, a second directivity segregation number different from the first directivity segregation number; and

repeatedly selecting in the remote base stations the first directivity segregation number, wherein one or more of the base stations is further configured to;

obtain allocation target slots as natural numbers into which an angle of a radio wave to a terminal station is classified;

obtaining allocation target slots different from each other by combining the obtained allocation target slots with the directivity segregation number of the base station; and

allocating slots to terminal stations around each of the allocation target slots.

16. The method according to claim 15, further including the steps of:

broadcasting common information to terminal stations over a plurality of broadcasting channel;

selecting a broadcasting channel different from those of adjacent base stations to avoid interference from adjacent base stations;

setting a number of broadcasting channels to be the same as the number of directivity segregation; and

selecting the directivity segregation number correlated to the selected broadcasting channel.