Methods and techniques in channel assignment in a cellular network

• US 6,728,544 B1
• Filed: 12/15/1999
• Issued: 04/27/2004
• Est. Priority Date: 12/15/1999
• Status: Expired due to Fees

• Current Assignee: Verizon Laboratories Incorporated (Verizon Communications Inc.)
• Original Assignee: Verizon Laboratories Incorporated (Verizon Communications Inc.)
• Inventors: Freeman, David R., Boyer, Pete A., Vicharelli, Pablo, Rossoni, Philip G.
• Primary Examiner(s): Trinh, Sonny
• Application Number:
  US09/461,990
• Time in Patent Office: 1,595 Days
• Field of Search: 455/446, 455/447, 455/450, 455/452.1, 455/452.2, 455/422.1, 455/464, 455/509, 455/451, 455/507, 455/453, 455/455, 455/524, 455/525
• US Class Current: 455/450
• CPC Class Codes: H04W 16/10 Dynamic resource partitioning
• CPC Class Codes: H04W 16/18 Network planning tools
• CPC Class Codes: H04W 28/16 Central resource management; Negotiation of resources or communication parameters, e.g. negotiating bandwidth or QoS [Quality of Service]

Abstract

A cellular network configuration tool is described that performs frequency assignments for use in a cellular network. The channels are assigned in accordance with input configuration data such as a channel separation matrix, geographic data, and requested channel assignments for each sector included in the cellular network being configured. The configuration is performed in accordance with predetermined constraints and criteria and quality of service input. The tool uses frequency assignment techniques to perform the channel assignments in accordance with varying constraints and criteria.

Claims

1. A method executed in a computer system for performing channel assignments in a cellular network, the method comprising:

selecting a first set of selection criteria in accordance with a desired level of computational complexity; and

determining a channel assignment in accordance with the first set of selection criteria,

wherein selecting the first set of selection criteria includes;

determining a first time estimate for a single channel assignment in accordance with the first set of selection criteria;

determining a total time estimate using the first time estimate; and

comparing the total time estimate with a predetermined time threshold.

2. The method of claim 1, further comprising:

determining a second set of selection criteria based on comparing the total time estimate with the pre-determined time threshold.

3. The method of claim 2, wherein at least one of the first and second set of selection criteria includes frequency selection criteria.

4. The method of claim 2, wherein at least one of the first and second set of selection criteria includes sector selection criteria.

5. The method of claim 1, wherein determining the first time estimate comprises:

performing a total carrier to interference calculation.

6. The method of claim 1, wherein determining the first time estimate comprises:

adjusting a bias used in determining subsequent channel assignments.

7. The method of claim 6, wherein adjusting comprises:

adjusting the bias based on comparing the total time estimate with the pre-determined time threshold.

8. The method of claim 1, wherein determining a channel assignment comprises:

selecting one or more assignment criteria from a plurality of assignment criteria options; and

determining the channel assignment using carrier to interference values and a predetermined threshold in accordance with the one or more assignment criteria, the carrier to interference values being determined by considering carrier signal strength and interference signal strength when both the carrier and the interference signals operate at a first frequency, the predetermined threshold representing a quality of service criteria.

9. The method of claim 8, further comprising:

using the carrier to interference values in evaluating one or more channel assignments for a cellular network.

10. The method of claim 8, further comprising:

using a first set of carrier to interference values and a second set of carrier to interference values in evaluation of alternative channel assignments.

11. The method of claim 1, wherein the first set of selection criteria include frequency selection criteria.

12. The method of claim 1, wherein the first set of selection criteria include sector selection criteria.

13. The method of claim 1, wherein determining a channel assignment comprises:

performing a total carrier to interference calculation.

14. The method of claim 1, wherein determining a channel assignment comprises:

adjusting a bias used in determining subsequent channel assignments.

15. A method executed in a computer system for determining channel assignments, the method comprising:

selecting a set of assignment criteria from a plurality of assignment criteria options;

determining for each pair of sectors included in a cellular network whether each pair are probable neighbors;

determining pairwise carrier to interference values for each pair of sectors including a first and a second sector if the pairwise carrier to interference values are included in the selected set of assignment criteria, the first sector having a carrier value and the second sector having an interference value, the first and second sectors operating at the same frequency; and

using the probable neighbors and the pairwise carrier to interference values in determining whether to perform a channel assignment for the cellular network, the channel assignment associating one or more channels with each sector included in the cellular network.

16. The method of claim 15, further comprising:

determining contiguous regions for servers in accordance with geographic areas;

determining total and common boundary measurements for each sector included in the servers, the total boundary measurement representing a boundary surrounding the geographic area associated with each sector, the common boundary measurement representing a boundary corresponding to a geographic area common between one of the pairs of sectors; and

determining if one of the pairs of sectors are probable neighbors in accordance with the total and the common boundary measurements associated with the one pair of sectors.

17. The method of claim 16, wherein, for each pair of sectors including a first and a second sector, the method further comprises:

determining a first ratio of a common boundary common between the first and the second sectors to a total boundary for the first sector; and

comparing the first ratio with a first predetermined boundary threshold.

18. The method of claim 17, wherein for each pair of sectors, the method further comprises:

determining a second ratio of a common boundary common between the first and the second sectors to a total boundary for the second sector; and

comparing the second ratio with a second predetermined boundary threshold.

19. The method of claim 18, further comprising:

determining that the first and the second sectors are probable neighbors based on comparing the first ratio with the first predetermined boundary threshold and the second ratio with the second predetermined boundary threshold.

20. The method of claim 19, wherein the first and second predetermined boundary thresholds are the same.

21. A method executed in a computer system for performing channel assignments in a cellular network, the method comprising:

selecting a first set of selection criteria in accordance with a desired level of computational complexity; and

determining a channel assignment in accordance with the first set of selection criteria, wherein determining the channel assignment includes;

selecting a set of assignment criteria from a plurality of assignment criteria options;

determining, in accordance with the set of assignment criteria, pairwise carrier to interference values for each pair of sectors including a first and a second sector, the first sector having a carrier value and the second sector having an interference value, the first and the second sectors operating at the same frequency; and

determining total carrier to interference values by combining one or more pairwise carrier to interference values.

22. The method of claim 21, wherein the total carrier to interference values include a co-channel carrier to interference value and an adjacent channel carrier to interference value.

23. The method of claim 22, wherein the co-channel carrier to interference value is computed as:

${\left(C/I\right)}_{j,i}=\frac{1}{\sum <br><br>\frac{1}{{\left(C/I\right)}_{k,j<br><br>\text{\hspace{1em}<br><br>}<br><br>\mathrm{pairwise}}}}$

wherein the summation is for all k such that channel i is assigned to sector k.

24. The method of claim 22, wherein the adjacent channel carrier to interference value is computed as:

${\left(C/I\right)}_{j,i}=\frac{1}{\sum <br><br>\frac{1}{{\left(C/I\right)}_{k,j<br><br>\text{\hspace{1em}<br><br>}<br><br>\mathrm{pairwise}}}}$

wherein the summation is for all k such that sector k is an adjacent channel being one of channel i−

1 or channel i+1.

25. The method of claim 21, further comprising:

performing frequency assignments to two or more sectors in accordance with the total carrier to interference values and a predetermined threshold.

26. The method of claim 21, wherein determining pairwise carrier to interference values comprises:

determining a probability density for each portion of a best server area;

weighting the probability density in accordance with cellular network traffic associated with portions of the best server area; and

determining a pairwise carrier to interference value in accordance with a percentile of the probability density.

27. The method of claim 21, wherein the first set of selection criteria include frequency selection criteria.

28. The method of claim 21, wherein the first set of selection criteria include sector selection criteria.

29. The method of claim 21, wherein determining the channel assignment comprises:

performing a total carrier to interference calculation.

30. The method of claim 21, wherein determining the channel assignment comprises:

adjusting a bias used in determining subsequent channel assignments.

31. A computer program product for determining channel assignments, the computer program product comprising:

means for selecting a set of assignment criteria from a plurality of assignment criteria options;

means for determining for each pair of sectors included in a cellular network whether each pair are probable neighbors;

means for determining pairwise carrier to interference values for each pair of sectors including a first and a second sector if the pairwise carrier to interference values are included in the selected set of assignment criteria, the first sector having a carrier value and the second sector having an interference value, the first and the second sectors operating at the same frequency; and

means for using the probable neighbors and the pairwise carrier to interference values in determining whether to perform a channel assignment for the cellular network, the channel assignment associating one or more channels with each sector included in the cellular network.

32. The computer program product of claim 31, further comprising:

means for determining contiguous regions for servers in accordance with geographic areas;

means for determining total and common boundary measurements for each sector included in the servers, the total boundary measurement representing a boundary surrounding the geographic area associated with each sector, the common boundary measurement representing a boundary corresponding to a geographic area common between one of the pairs of sectors; and

means for determining if one of the pairs of sectors are probable neighbors in accordance with the total and the common boundary measurements associated with the one pair of sectors.

33. A computer program product for performing channel assignments in a cellular network, the computer program product comprising:

machine executable code for selecting a first set of selection criteria in accordance with a desired level of computational complexity; and

machine executable code for determining a channel assignment in accordance with said first set of selection criteria,

wherein machine executable code for determining the channel assignment includes

machine executable code for selecting a set of assignment criteria from a plurality of assignment criteria;

machine executable code for determining, in accordance with the set of assignment criteria, pairwise carrier to interference values for each pair of sectors including a first and a second sector, the first sector having a carrier value and the second sector having an interference value, the first and the second sectors operating at the same frequency; and

machine executable code for determining total carrier to interference values by combining one or more pairwise carrier to interference values.

34. The computer program product of claim 33, wherein the total carrier to interference values include a co-channel carrier to interference value and an adjacent channel carrier to interference value.