Adaptive frequency reuse plan

• US 5,974,324 A
• Filed: 02/10/1997
• Issued: 10/26/1999
• Est. Priority Date: 02/10/1997
• Status: Expired due to Term

• Current Assignee: Optis Cellular Technology LLC (Brevet Capital)
• Original Assignee: Ericsson, Inc. (Telefonaktiebolaget LM Ericsson)
• Inventors: Henson, Steven Ray
• Primary Examiner(s): Urban, Edward F.
• Application Number:
  US08/797,404
• Time in Patent Office: 988 Days
• Field of Search: 455/446, 455/447, 455/450, 455/452, 455/453, 455/524, 455/62, 455/63
• US Class Current: 455/447
• CPC Class Codes: H04W 16/12 Fixed resource partitioning
• CPC Class Codes: H04W 16/24 Cell structures

Abstract

A cell pattern for use with a frequency reuse plan is disclosed. Seven clusters each comprising N cells per cluster are grouped together as a modified cluster. Each cell is further divided into three sectors. The total number of available frequency channels are divided into a F times seven (F*7) number of groups. Frequency channels associated with a group are then assigned to each of the cells within the modified cluster. In order to increase call capacity within a particular sector, a frequency channel previously assigned to a corresponding sector within the same cell group is reused. Within a continuing increase in channel re-usage within a particular modified cluster, the (N*7)/(F*7) reuse plan is gradually lowered to the original N/F reuse plan without re-configuring the frequency allocation throughout the network.

Claims

1. A method for assigning T number of frequency channels within a cellular telecommunications network having a plurality of cells, wherein N cells are arranged as a cluster, said method comprising the steps of:

associating C contiguous clusters together as a modified cluster, a plurality of said modified clusters covering a geographic area;

labeling said N cells within each of said C contiguous clusters according to a cell labeling order;

associating cells from two or more clusters having a same cell label as a cell group;

sequentially assigning said T number of frequency channels within each of said plurality of modified clusters; and

reusing, in a first cell in a first cluster, a frequency channel assigned to a second cell within a second cluster, said second cell within the same cell group as said first cell in order to increase capacity within said first cell of said first cluster.

2. The method of claim 1 further comprising the steps of:

dividing each of said N cells into D sectors;

labeling said D sectors according to a sector labeling order; and

reusing, in a first sector of said first cell in said first cluster, a frequency channel assigned to a second sector of said second cell within said second cluster with the same sector label as said first sector in order to increase capacity within said first sector of said first cell of said first cluster.

3. The method of claim 2 wherein said D number of sectors includes three (3) sectors within each cell.

4. The method of claim 2 wherein said step of assigning said T number of frequency channels further comprises the steps of:

(A) sequentially assigning a first portion of said T number of frequency channels to first sectors with a first sector label within each of said N number of cells associated with a first cluster within said modified cluster until each of said first sectors has been assigned a frequency channel from said first portion;

(B) sequentially assigning an additional portion of said T frequency channels to next sectors with a next sector label up to D sector labels within each of said N number of cells associated with said first cluster until each of said D sectors has been assigned a frequency channel from said additional portion; and

(C) sequentially assigning a remaining portion of said T frequency channels by repeating steps (A)-(B) for a next cluster up to C contiguous clusters within said modified cluster until N*C*D sectors have been assigned a frequency channel from said remaining portion and further repeating steps (A)-(B) using said remaining portion until each of said T number of frequency channels is assigned.

5. The method of claim 1 wherein said step of reusing further comprises the steps of:

reusing, in said first cell, first additional frequency channels assigned to said second cell until all of said first additional frequency channels are reused; and

reusing, in said first cell, second additional frequency channels assigned to a third cell of a third cluster, said third cell from the same cell group as said first cell.

6. The method of claim 1 wherein said C contiguous clusters includes seven (7) contiguous clusters within said modified cluster.

7. A mobile telecommunications network for providing radio coverage within a particular geographic area, comprising:

a plurality of cells, each cell comprising D sectors;

a plurality of clusters, each cluster comprising N cells;

a plurality of modified clusters, each modified cluster comprising C contiguous clusters; and

a T number of frequency channels distributed over and reused within each of said plurality of modified clusters, wherein said T number of frequency channels are reused according to a reuse plan whereby a first frequency channel is reused within a first sector associated with a first cluster, said first frequency channel assigned to a second sector associated with a second cluster wherein the difference in channel numbers assigned to said first sector and said first frequency channel being reused from said second sector is at least D times C.

8. The mobile telecommunications network of claim 7 wherein each of said D sectors is initially assigned more than one frequency channel with channel numbers N*C*D apart.

9. The mobile telecommunications network of claim 8 wherein said C includes a numerical value of seven (7).

10. The mobile telecommunications network of claim 7 wherein said D includes a numerical value of three (3).

11. A cell structure for use with a frequency reuse pattern, comprising:

a plurality of cells, each cell comprising a plurality of sectors;

a plurality of clusters, each cluster comprising an N number of cells from said plurality of cells;

a plurality of modified clusters;

a T number of frequency channels wherein said T number of frequency channels are divided into F number of frequency groups and distributed over and reused within each of said plurality of modified clusters;

a plurality of sub-frequency groups formed from said F number of frequency groups, wherein each of said plurality of sectors is assigned frequency channels associated with one of said plurality of sub-frequency groups; and

wherein in order to increase the capacity for a first sector within a first cluster, a frequency channel assigned to a second sector associated with a second cluster is reused within said plurality of modified clusters, the difference in channel numbers between said frequency channels already assigned to said first sector and said channel frequency being reused from said second sector is at least twenty-one.

12. The cell structure of claim 11, wherein in order to further increase the capacity for said first sector, a frequency channel from a third sector within a third cluster is reused in said first sector only after all frequency channels from said second sector have been reused by said first sector.

13. A method for adaptively changing a first reuse plan to a second reuse plan within a cellular telecommunications network, said method comprising the steps of:

associating N cells as a cluster;

associating a plurality of clusters as a modified cluster;

distributing T number of frequency channels within said modified cluster according to said first reuse plan by;

assigning a first group of frequency channels to a first cell in a first cluster; and

assigning a second group of frequency channels to a second cell in a second cluster, wherein said first group is different from said second group; and

reusing, in order to accommodate an increase in call capacity within said first cell, frequency channels from said second group of frequency channels within said first cell to adaptively change to said second reuse plan.

14. The method of claim 13, wherein said step of reusing further includes reusing, within said first cell associated with a first cluster within said modified cluster, a first frequency channel assigned to said second cell associated with a second cluster within the same modified cluster wherein the difference in channel numbers between a second frequency channel assigned to said first cell and said first frequency channel reused from said second cell is at least seven.

15. The method of claim 13 further comprising the steps of:

partitioning each cell within said modified cluster into D number of sectors; and

assigning said D number of sectors one or more of said T number of frequency channels according to said first reuse plan.

16. The method of claim 15 further comprising the step of reusing, within a first sector within said first cell of a first cluster within said modified cluster, a first frequency channel assigned to a second sector within said second cell of said second cluster within said modified cluster, wherein the difference in channel numbers between a second frequency channel assigned to said first sector and said first frequency channel being reused from said second sector is at least twenty-one.

17. The method of claim 16, wherein said step of reusing further includes the step of reusing a third frequency channel from a third sector within a third cluster only after all frequency channels from said second sector have been reused.

18. The method of claim 13 wherein said N includes a numerical value of seven (7).

19. A method for automatically adapting from a first reuse plan to a second reuse plan within a cellular telecommunications network having a plurality of cells divided into one or more sectors, said method comprising the steps of:

associating N cells in a predetermined sequence as a cluster;

associating M clusters as a modified cluster having M*N cells;

associating cells from each of said M clusters having a same respective sequence position as a cell group;

distributing T number of frequency channels within said modified cluster such that each of said T number of frequency channels is assigned to only one of said M*N cells in said modified cluster to establish said first reuse plan;

adapting from said first reuse plan to said second reuse plan by reusing said T number of frequency channels within said N cell groups to establish said second reuse plan.

20. The method of claim 19 wherein said step of adapting further comprises the steps of:

a) reusing, in a first cell of a corresponding cell group, one or more frequency channels assigned to a second cell in said corresponding cell group until all of said one or more frequency channels are reused; and

b) reusing, in said first cell, a second one or more frequency channels assigned to one or more additional cells in said corresponding cell group not to exceed a maximum of M cells, until all of said second one or more frequency channels are reused.

21. The method of claim 20 wherein said step of adapting further comprises the steps of:

repeating steps a) and b) of claim 20 for each of said M corresponding cells in said N cell groups until said second reuse plan is established for said modified cluster such that said each of said M corresponding cells in said N cell groups is assigned an identical group of said T number of frequency channels.

22. The method of claim 19 wherein said step of adapting further comprises the steps of:

a) reusing, in a first sector of a first cell of a corresponding cell group, one or more frequency channels assigned to a second sector of a second cell in said corresponding cell group until all of said one or more frequency channels are reused; and

b) reusing, in said first sector of said first cell, a second one or more frequency channels assigned to one or more additional sectors of additional cells in said corresponding cell group not to exceed a maximum of M cells, until all of said second one or more frequency channels are reused.

23. The method of claim 22 wherein each of said M cells in said N cell groups further includes a plurality of sectors and said step of adapting further comprises the steps of:

repeating steps a) and b) of claim 22 for each of said plurality of sectors of said M corresponding cells in said N cell groups until said second reuse plan is established for said modified cluster such that said each of said plurality of sectors in said M corresponding cells in said N cell groups is assigned an identical group of said T number of frequency channels.