System and method for managing neighbor-channel interference in channelized cellular systems

• US 5,740,536 A
• Filed: 12/29/1995
• Issued: 04/14/1998
• Est. Priority Date: 12/29/1995
• Status: Expired due to Term

• Current Assignee: AT&T Corporation (AT&T, Inc.)
• Original Assignee: AT&T Corporation (AT&T, Inc.)
• Inventors: Benveniste, Mathilde
• Primary Examiner(s): Vo, Nguyen
• Assistant Examiner(s): Armstrong, Darnell R.
• Application Number:
  US08/580,570
• Time in Patent Office: 837 Days
• Field of Search: 455/33.1, 455/32.2, 455/56.1, 455/54.1, 455/63, 455/296, 455/450, 455/446, 455/452, 455/451, 455/449, 455/447, 455/62
• 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

Novel methodologies are provided for managing neighbor channel interference in a cellular wireless communications system as a function of a service-quality factor for a communications channel within such a system. Those methodologies, and their essential function are characterized as:

Even/Odd Cell Designation--for eliminating adjacent-channel conflicts within a cell;

Vertical Channel-Set Construction--for eliminating adjacent-channel conflicts between abutting sectors in sectorized cells; and

Minimum Adjacency Circuit Method--for reducing the number of adjacent edges between abutting cells or sectors in a regular channel assignment.

Claims

1. In a wireless communication network having service areas partitioned into a plurality of cells, wherein a second plurality of communication channels are available for allocation among cells and at least a portion of said channels are successively disposed along a frequency continuum, a method for avoiding use of any two of said channels having adjacent frequencies within a common cell, and reducing co-channel and neighbor channel interference, comprising the steps of:

arranging channels into disjoint categories by the steps of assigning odd/even parity to each cell and assigning to cells channels with numbers of the assigned parity;

arranging channels into a number of vertical columns equal to a reuse factor with a plurality of vertical groupings across all columns for identifying channels for sectors of cells.

determining adjacent edges between adjacent cells in a system which define the existence of adjacent channels in adjacent cells and from vertical listings of available channels.

2. In a wireless communication network having service areas partitioned into a plurality of cells, wherein a second plurality of communication channels are available for allocation among cells and at least a portion of said channels are successively disposed along a frequency continuum, a method for avoiding use of any two of said channels having adjacent frequencies within a common cell, and reducing co-channel and neighbor channel interference, comprising the steps of:

arranging channels into disjoint categories by the steps of assigning odd/even parity to each cell and assigning to cells channels with numbers of the assigned parity;

determining adjacent edges between adjacent cells in a system which define the existence of adjacent channels in adjacent cells and constructing a neighbor graph with nodes corresponding to cells in a reuse cluster; and

assigning channels in a way so as to minimize adjacent edges;

constructing channel sets for individual cell by selecting channels from one disjoint set, and by determining adjacent edges to identify adjacent channel interference and reduce adjacent edges in channel selection.

3. A method of managing co-channel, neighbor channel and adjacent channel interference in a wireless communications network having service areas partitioned into a plurality of cells, wherein a second plurality of communication channels derived from a defined frequency spectrum are available for allocation among cells, said method comprising the steps of:

causing a transmission pattern in said cells in at least one of said service areas to be directed among a plurality of sectors;

partitioning said plurality of communications channels into a plurality of disjoint segments, said plurality of segments being numerically equal to said plurality of sectors, wherein each said partition of said communications channels in each said disjoint segment is comprised of essentially contiguous channels;

constructing a table of channels in a vertical set construction having listings of the numbers in sequence with cyclic repeats from column to column;

the table comprising a predefined channel set wherein a number of columns in said table correspond to individual cells from a predetermined grouping of said cells to be served by channels in said channel set and further wherein said channels shown in each of said columns of said table are assigned to said corresponding cell;

dividing each of said columns into portions related to said segments in said plurality of disjoint segments.

4. A method for managing neighbor channel interference in a wireless communication system in which channel reuse is defined by assignment of channels to a pattern of a plurality of cells defining service areas, comprising the steps of:

designating alternate individual cells with even/odd numbers combined with providing disjoint frequency lists so that adjacent channel conflicts do not arise in neighboring cells;

organizing channel sets between abutting sectors in sectorized cells into a tabulated vertical channel-set construction; and

minimizing numbers of adjacent edges between abutting cells or sectors.