Directional frequency allocation in an N=6 cellular radio system

• US 5,802,474 A
• Filed: 06/20/1996
• Issued: 09/01/1998
• Est. Priority Date: 06/20/1996
• Status: Expired due to Term

• Current Assignee: RPX Clearinghouse LLC (RPX Corporation)
• Original Assignee: Northern Telecom Limited (Nortel Networks Corporation)
• Inventors: Faruque, Saleh
• Primary Examiner(s): Eisenzopf, Reinhard J.
• Assistant Examiner(s): Bhattacharya, Sam
• Application Number:
  US08/667,831
• Time in Patent Office: 803 Days
• Field of Search: 455/62, 455/63, 455/422, 455/446, 455/447, 455/448, 455/450, 455/452, 455/524
• US Class Current: 455/447
• 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

Abstract

The process of the present invention is based on a tri-cellular platform where nine, or a multiple of nine, frequency groups are directionalized and reused in the same direction. Directional antennas are located in the center of the tri-cell group. Each antenna radiates into a 120° sector of each cell, effectively radiating the entire cell from the corner. The reused frequency groups are aligned along the 0°, 120°, and 240° axes of each tri-cell group. The frequency groups are reused in the same direction along each axis, reducing the number of dominant interfering cells to one.

Claims

1. A method for frequency allocation in a cellular system, the cellular system having a plurality of available frequencies and comprising a plurality of cells, the method comprising the steps of:

forming a tri-cell group from three of the plurality of cells, the tri-cell group having three axes of frequency use;

forming a cellular cluster from seven of the at least one tri-cell groups, the cellular cluster having a plurality of layers for each frequency use axis;

grouping the plurality of available frequencies into a predetermined number of frequency groups;

locating a plurality of antennas substantially in the center of each tri-cell group, each antenna of the plurality of antennas radiating into a predetermined sector of the tri-cell group; and

allocating the frequency groups such that a first frequency group is used only along a first frequency use axis, of the three frequency use axes, in the cellular cluster.

2. The method of claim 1 wherein the predetermined sector is a 120°

sector that covers a cell of the tri-cell group.

3. The method of claim 1 and further including the step of repeating the cellular cluster to cover a geographical region.

4. The method of claim 1 wherein the step of allocating the frequency groups further includes allocating the frequency groups such that the first frequency group alternates with a second frequency group along the first frequency use axis.

5. The method of claim 1 wherein the predetermined number of frequency groups is equal to a multiple of 9.

6. The method of claim 1 wherein the predetermined number of frequency groups is equal to a multiple of 12.

7. A method for frequency allocation in a cellular system, the cellular system having a plurality of available frequencies and comprising a plurality of cells, the method comprising the steps of:

forming a tri-cell group comprising three of the plurality of cells, the tri-cell group having three axes of frequency use;

forming a cellular cluster from seven of the tri-cell groups, the cellular cluster having a plurality of layers for each frequency use axis;

grouping the plurality of available frequencies into a multiple of 9 frequency groups;

locating a plurality of antennas in a location that is substantially central to each of the tri-cell groups, each antenna radiating a 120°

pattern such that each antenna radiation pattern substantially covers a different cell of the tri-cell group; and

assigning a first frequency group of the multiple of 9 frequency groups to each antenna such that the first frequency group is continuously repeated along a first axis, of the three frequency use axes, of the cellular cluster.

8. A cellular communication system for the efficient reuse of a plurality of channel frequencies, the system comprising:

a plurality of cells that are grouped into tri-cell groups comprising three cells of the plurality of cells, the tri-cell groups being further grouped into cellular clusters comprising seven tri-cell groups, each tri-cell group having a plurality of frequency use axes;

a plurality of directional antennas located substantially in the center of each tri-cell group, each antenna oriented such that it radiates into a different cell of the tri-cell group; and

a plurality of transceivers coupled to the plurality of antennas, each transceiver operating on at least one channel frequency of the plurality of channel frequencies such that a first and a second channel frequency alternate along each frequency use axis.

9. A cellular communication system for the efficient reuse of a plurality of channel frequencies, the system comprising:

a plurality of cells that are grouped into tri-cell groups comprising three cells of the plurality of cells, the tri-cell groups being further grouped into cellular clusters comprising seven tri-cell groups, each tri-cell group having a plurality of frequency use axes;

a plurality of directional antennas located substantially in the center of each tri-cell group, each antenna oriented such that it radiates into a different cell of the tri-cell group; and

a plurality of transceivers coupled to the plurality of antennas, each transceiver operating on at least one channel frequency of the plurality of channel frequencies such that a first channel frequency is reused only along a first frequency use axis of the plurality of frequency use axes.