Automated, dynamic minimization of inter-cell site interference in CDMA networks

Patent metadata

Field	Value
Publication number	US-10887040-B2
Application number	US-201816218110-A
Country	US
Kind code	B2
Filing date	Dec 12, 2018
Priority date	Mar 14, 2014
Publication date	Jan 5, 2021
Grant date	Jan 5, 2021

Abstract

Methods and apparatus for allocating scrambling codes to cells of a wireless network. In an example method, current scrambling code allocation information for a plurality of cells and network configuration information for a radio access network are received. A reallocation of scrambling codes to the plurality of cells is computed, based on the current scrambling code allocation information and the network configuration information, using a metaheuristic algorithm. A change in scrambling code for at least one of the plurality of cells is then triggered, based on the computed reallocation. In some embodiments, the metaheuristic algorithm is based on an objective function that comprises a summation of interference metrics for each of the plurality of cells, wherein the interference metrics depend on scrambling code allocations to the plurality of cells. In some embodiments, a simulated annealing metaheuristic is used.

First claim

What is claimed is:

1. A method, in a network management node operatively connected to a radio access network that comprises a plurality of cells, for allocating scrambling codes to the cells, the method comprising:
receiving current scrambling code allocation information for the plurality of cells and receiving network configuration information for the radio access network;
computing a reallocation of scrambling codes to the plurality of cells, based on the current scrambling code allocation information and the network configuration information, using a metaheuristic algorithm, wherein the metaheuristic algorithm is based on an objective function that comprises a summation of interference metrics for each of the plurality of cells and wherein the interference metrics depend on scrambling code allocations to the plurality of cells; and
triggering a change in scrambling code for at least one of the plurality of cells, based on the computed reallocation.

2. The method of claim 1 , wherein the metaheuristic algorithm employs a simulated annealing metaheuristic.

3. The method of claim 1 , wherein a predetermined number of scrambling codes are changed from each iteration of the metaheuristic algorithm to the next.

4. The method of claim 3 , wherein the predetermined number is 1.

5. The method of claim 1 , wherein scrambling code changes from each iteration of the metaheuristic algorithm to the next are tested to ensure that there are no duplicate scrambling codes among neighboring cells.

6. The method of claim 5 , further comprising determining neighbor cells for at least some of the plurality of cells based at least in part on neighbor cell information obtained from one or more radio network controllers.

7. The method of claim 5 , further comprising determining neighbor cells for at least some of the plurality of cells based at least in part on geo-positioning information for at least some of the plurality of cells.

8. The method of claim 1 , further comprising, after the reallocation has been computed, testing the computed reallocation to ensure that there are no duplicate scrambling codes among neighboring cells.

9. The method of claim 1 , wherein at least the computing operation of claim 1 is repeated at pre-determined intervals.

10. The method of claim 1 , wherein at least the computing and triggering operations are initiated in response to a problem detection in the radio access network.

11. The method of claim 1 , wherein at least the computing and triggering operations are initiated in response to an addition of a new cell to the radio access network.

12. A network management node, comprising:
communications interface circuitry configured to communicate with one or more nodes in a radio access network, and
a processing circuit configured to control the communications interface circuitry and to:
receive current scrambling code allocation information for the plurality of cells and receive network configuration information for the radio access network;
compute a reallocation of scrambling codes to the plurality of cells, based on the current scrambling code allocation information and the network configuration information, using a metaheuristic algorithm, wherein the metaheuristic algorithm is based on an objective function that comprises a summation of interference metrics for each of the plurality of cells and wherein the interference metrics depend on scrambling code allocations to the plurality of cells; and
trigger a change in scrambling code for at least one of the plurality of cells, based on the computed reallocation.

13. The network management node of claim 12 , wherein the metaheuristic algorithm employs a simulated annealing metaheuristic.

14. The network management node of claim 12 , wherein the processing circuit is configured to change a predetermined number of scrambling codes from each iteration of the metaheuristic algorithm to the next.

15. The network management node of claim 12 , wherein the processing circuit is configured to test scrambling code changes from each iteration of the metaheuristic algorithm to the next to ensure that there are no duplicate scrambling codes among neighboring cells.

16. The network management node of claim 15 , wherein the processing circuit is further configured to determine neighbor cells for at least some of the plurality of cells based at least in part on neighbor cell information obtained from one or more radio network controllers (RNCs).

17. The network management node of claim 15 , wherein the processing circuit is further configured to determine neighbor cells for at least some of the plurality of cells based at least in part on geo-positioning information for at least some of the plurality of cells.

18. The network management node of claim 12 , wherein the processing circuit is further configured to test, after the reallocation has been computed, the computed reallocation, to ensure that there are no duplicate scrambling codes among neighboring cells.

19. A network management node, comprising:
communications interface circuitry configured to communicate with one or more nodes in a radio access network, and
a processing circuit configured to control the communications interface circuitry and to:
receive current scrambling code allocation information for the plurality of cells and receive network configuration information for the radio access network;
compute a reallocation of scrambling codes to the plurality of cells, based on the current scrambling code allocation information and the network configuration information, using a metaheuristic algorithm;
test the computed reallocation, after the reallocation has been computed, to ensure that there are no duplicate scrambling codes among neighboring cells; and
trigger a change in scrambling code for at least one of the plurality of cells, based on the computed reallocation.

Assignees

• Ericsson Telefon Ab L M

Inventors

• Joshi Monil
• El Chebib Nader
• El-Najjar Jad

Classifications

• H04W72/541

  using the level of interference · CPC title

• H04L41/08

  Configuration management of networks or network elements (address allocation H04L61/50) · CPC title

• H04J13/16 Primary

  Code allocation · CPC title

• H04W88/08

  Access point devices · CPC title

• H04J11/005

  of intercell interference · CPC title