Method and system for solving cellular communications frequency planning problem

• US 6,178,328 B1
• Filed: 06/11/1998
• Issued: 01/23/2001
• Est. Priority Date: 06/11/1998
• Status: Expired due to Term

• Current Assignee: RPX Clearinghouse LLC (RPX Corporation)
• Original Assignee: Nortel Networks Corporation
• Inventors: Djurkovic, Roderick, Tang, Yuqiang
• Primary Examiner(s): Eisenzopf, Reinhard J.
• Assistant Examiner(s): Aoki, Makoto
• Application Number:
  US09/096,426
• Time in Patent Office: 957 Days
• Field of Search: 455/446, 455/447, 455/450, 455/449
• 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 16/18 Network planning tools
• CPC Class Codes: H04W 16/24 Cell structures

Abstract

A method and system for use with wireless communications systems having a plurality of groups of channels, and wherein the method and system assign specific groups of channels such that channel interference is minimized. The method and system accomplish their objects via the use of communications equipment adapted to do the following: define a geographic area; map the defined geographic area with at least one high bandwidth cell cluster wherein each cell has at least one sector; and eliminate channel adjacencies by selectively assigning channels, drawn from the plurality of groups of channels, to the at least one high bandwidth cell cluster. The method and system further accomplish their objects via the use of communications equipment adapted to do the following: select a frequency reuse table having a predefined frequency reuse factor; and define a high bandwidth cell cluster over which the frequency reuse table is utilized such that the defined frequency reuse factor is effectively maintained while the communications efficiency of a wireless communications system is enhanced.

Claims

1. A method for channel allocation in a wireless communications system having a plurality of groups of channels, said method comprising the steps of:

mapping a geographic area with a high bandwidth cell cluster, wherein each cell in said high bandwidth cell cluster is comprised of a plurality of sectors;

reserving at least one channel group from said plurality of groups of channels to provide at least one reserved channel group and at least one non-reserved channel group; and

selectively assigning a channel group from said plurality of groups of channels to each cell within said high bandwidth cell cluster by first assigning a channel group from among said at least one non-reserved channel group to each cell of said high bandwidth cell cluster and then assigning a channel group from among said at least one reserved channel group to pairs of adjacent cells among said high bandwidth cell cluster is in which channel group adjacencies exists, wherein said channel group adjacencies are substantially eliminated and high bandwidth is maintained.

2. The method of claim 1, wherein said step of mapping further includes the steps of:

defining a first basic cell cluster within which frequency groups are to be mapped;

defining a second basic cell cluster within which frequency groups are to be mapped; and

mapping the defined geographic area with the first and second basic cell clusters.

3. The method of claim 2, wherein said step of selectively assigning channels, further includes the steps of:

obtaining a frequency reuse table having a plurality of channel groups available for allocation to said first basic cell cluster and said second basic cell cluster, wherein said frequency reuse table further includes additional channel groups which are utilized for said at least one reserved channel group; and

assigning the plurality of channel groups to the first basic cell cluster and the second basic cell cluster.

4. The method of claim 1, wherein said high bandwidth cell cluster comprises a first high bandwidth cell cluster and said method further comprises the steps of:

obtaining a frequency reuse table having a plurality of channel groups wherein a first channel group is selectable as said at least one non-reserved channel group and a second channel group is selectable as said at least one reserved channel group;

determining a number of cells in said first high bandwidth cell cluster for which said frequency reuse table was generated;

mapping said geographic area with a second high bandwidth cell cluster adjacent to said high bandwidth cell cluster; and

assigning said unreserved channels and said reserved channels to both said first high bandwidth cell cluster and said second high bandwidth cell cluster, wherein channels are assigned in a manner which substantially maximizes spacing between adjacent channels in cells of both said first high bandwidth cell cluster and said second high bandwidth cell cluster.

5. The method of claim 4, further comprising the steps of:

subdividing the at least one reserved channel group into at least two subgroups; and

assigning the at least two subgroups to separate sectors within at least one cell among the first high bandwidth cell cluster and the second high bandwidth cell cluster such that channels of the at least one reserved channel group are spread among different sectors to substantially maximize separation of said channels within a cell and within adjacent cells.

6. The method of claim 4, further comprising the steps of:

reserving at least one channel for control information; and

assigning the at least one control channel such that interference on the control channel is substantially minimized.

7. The method of claim 1, further comprising the steps of:

reserving at least one channel for control information; and

assigning the at least one control channel such that interference on the control channel is substantially minimized.

15. The method of claim 1, further comprising the steps of:

determining when said channel group adjacencies exist among said pairs of adjacent cells, said pairs comprising a first cell and a second cell;

in response to said determining step, assigning said channel group from said at least one reserved channel group to a sector of said first cell, wherein said sector is directly adjacent to a next sector of said second cell, wherein channel group adjacencies are substantially eliminated in directly adjacent sectors of said pairs of adjacent cells.

16. The method of claim 1, further comprising the step of empirically determining an allocation scheme for channels within said at least one reserved channel group, wherein said allocation scheme substantially removes all channel adjacencies in adjacent cells and adjacent sectors when said channels of said at least one non-reserved channel group are assigned to said cell cluster.

17. The method of claim 5, said method implemented within a data processing system as a program product on a computer readable medium and further comprising the step of:

outputting an allocation scheme including an allocation of channels from both non-reserved and reserved channel groups and said at least one control channel, said allocation scheme providing said substantial separation between channels within each of said high bandwidth cell clusters and within said plurality of cell clusters.

8. A system for channel allocation in a wireless communications system having a plurality of groups of channels, and wherein said system assigns specific groups of channels such that channel interference is minimized, said system comprising:

means for mapping a geographic area with at least one high bandwidth cell cluster, wherein each cell in said high bandwidth cell cluster is comprised of a plurality of sectors;

means for reserving at least one channel group from said plurality of groups of channels to provide at least one reserved channel group and at least one non-reserved channel group; and

means for selectively assigning a channel group from said plurality of groups of channels to each cell within said high bandwidth cell cluster by first assigning a channel group from among said at least one non-reserved channel group to each cell of said high bandwidth cell cluster and then assigning a channel group from among said at least one reserved channel group to pairs of adjacent cells among said high bandwidth cell cluster in which channel group adjacencies exists, wherein said channel group adjacencies are substantially eliminated and high bandwidth is maintained.

9. The system of claim 8, wherein said means for mapping further includes:

means for defining a first basic cell cluster within which frequency groups are to be mapped;

means for defining a second basic cell cluster within which frequency groups are to be mapped; and

means for mapping the defining geographic area with the first and second basic cell clusters.

10. The system of claim 9, wherein said means for selectively assigning channels, further includes:

means for obtaining a frequency reuse table having a plurality of channel groups available for allocation to said first basic cell cluster and said second basic cell cluster, wherein said frequency reuse table further includes additional channel groups which are utilized for said at least one reserved channel group; and

means for assigning the plurality of channel groups to the first basic cell cluster and the second basic cell cluster.

11. The system of claim 8, wherein said high bandwidth cell cluster comprises a first high bandwidth cell cluster and said system further comprises:

means for obtaining a frequency reuse table having a plurality of channel groups, wherein a first channel group is selectable as said at least one non-reserved channel group and a second channel group is selectable as said at least one reserved channel group;

means for mapping said geographic area with a second high bandwidth cell cluster adjacent to said high bandwidth cell cluster; and

means for assigning said unreserved channels and said reserved channels to both said first high bandwidth cell cluster and said second high bandwidth cell cluster, wherein channels are assigned in a manner which substantially maximizes spacing between adjacent channels in cells of both said first high bandwidth cell cluster and said second high bandwidth cell cluster.

12. The system of claim 11, further including:

means for subdividing the at least one reserved channel group into at least two subgroups; and

means for assigning the at least two subgroups to separate sectors within at least one cell among the first high bandwidth cell cluster and the second high bandwidth cell cluster such that channels of the at least one reserved channel group are spread among different sectors to substantially maximize separation of said channels within a cell and within adjacent cells.

13. The system of claim 11, further comprising:

means for reserving at least one channel for control information; and

means for assigning the at least one control channel such that interference on the control channel is substantially minimized.

14. The system of claim 8, further comprising:

means for reserving at least one channel for control information; and

means for assigning the at least one control channel such that interference on the control channel is substantially minimized.

18. The system of claim 8, further comprising:

means for determining when said channel group adjacencies exist among said pairs of adjacent cells, said pairs comprising a first cell and a second cell;

means, in response to said determining means, for assigning said channel group from said at least one reserved channel group to a sector of said first cell, wherein said sector is directly adjacent to a next sector of said second cell, wherein channel group adjacencies are substantially eliminated in directly adjacent sectors of said pairs of adjacent cells.

19. The system of claim 8, further comprising means for empirically determining an allocation scheme for channels within said at least one reserved channel group, wherein said allocation scheme substantially removes all channel adjacencies in adjacent cells and adjacent sectors when said channels of said at least one non-reserved channel group are assigned to said cell cluster.