System and method for adaptive configuration of cell structure based on the position of mobile stations

• US 7,920,870 B1
• Filed: 12/30/1999
• Issued: 04/05/2011
• Est. Priority Date: 12/30/1999
• Status: Expired due to Fees

• Current Assignee: Ericsson, Inc. (Telefonaktiebolaget LM Ericsson)
• Original Assignee: Telefonaktiebolaget LM Ericsson
• Inventors: Bhatia, Ranjit, Zadeh, Bagher
• Primary Examiner(s): Vo; Nguyen T.
• Assistant Examiner(s): Afshar; Kamran
• Application Number:
  US09/475,324
• Time in Patent Office: 4,114 Days
• Field of Search: 455/444, 455/446, 455/450, 455/434, 455/422, 455/404, 455/403, 455/456.1, 455/452.2, 455/447, 455/436, 455/449, 455/443, 455/448, 370/252, 370/339, 370/340
• US Class Current: 455/444
• CPC Class Codes: H04W 16/32 Hierarchical cell structures
• CPC Class Codes: H04W 24/02 Arrangements for optimising operational condition
• CPC Class Codes: H04W 64/00 Locating users or terminals or network equipment for network management purposes, e.g. mobility management

Abstract

A telecommunications system and method is disclosed for adaptively configuring the cell structure of a cell having at least two carrier frequencies between an overlaid/underlaid (OL/UL) sub-cell structure and a normal cell structure based on the position of mobile stations within the cell. A Base Station Controller (BSC) for the cell determines the position of all of the mobile stations involved in a call connection within the cell relative to the cell site. If the number of mobile stations within a predefined distance from the cell site is greater than a channel threshold, the BSC adapts the cell configuration to the OL/UL sub-cell structure. The channel threshold is an operator-defined percentage of available channels (throughout the cell or within either the overlaid or underlaid cell). However, if the BSC determines that the percentage of mobile stations closer than the predefined distance is less than the channel threshold, the BSC maintains the normal cell structure.

Claims

1. A base station controller for adaptively configuring the structure of a cell served by said base station controller, said cell having a plurality of mobile stations located therein and a base transceiver station associated therewith, said base transceiver station having at least two carrier frequencies associated therewith, said base station controller comprising:

measurement logic adapted to determine a respective distance of each of said mobile stations involved in a call connection within said cell from said base transceiver station;

first comparison logic adapted to compare each said respective distance to a distance threshold to determine a number of said mobile stations having said respective distance less than or equal to said distance threshold;

second comparison logic adapted to perform a comparison of said number to a channel threshold; and

configuration logic adapted to switch between an overlaid/underlaid sub-cell structure having at least one of said at least two carrier frequencies serving only a portion of said cell and a normal cell structure having all of said at least two carrier frequencies serving the entire area of said cell based on the results of said comparison.

2. The base station controller of claim 1, wherein said channel threshold is a number of traffic channels in use.

3. The base station controller of claim 2, wherein said configuration logic is adapted to switch to said overlaid/underlaid sub-cell structure when the results of said comparison indicate that said number of said mobile stations having said respective distance less than or equal to said distance threshold is greater than or equal to said channel threshold.

4. The base station controller of claim 1, wherein said channel threshold is a number of traffic channels available.

5. The base station controller of claim 4, wherein said configuration logic is adapted to switch to said overlaid/underlaid sub-cell structure when the results of said comparison indicate that said number of said mobile stations having said respective distance less than or equal to said distance threshold is less than or equal to said channel threshold.

6. The base station controller of claim 1, further comprising:

a timer, said measurement logic being adapted to begin measuring each said respective distance upon the expiration of said timer.

7. The base station controller of claim 1, wherein each said respective distance is a radius around said base transceiver station, said distance threshold being an additional radius around said base transceiver station.

8. The base station controller of claim 1, wherein each said respective distance is a specific distance from said base transceiver station, said distance threshold being a radius around said base transceiver station.

9. The base station controller of claim 1, wherein each said respective distance is a specific distance from said base transceiver station, said distance threshold being a function describing the shape of an overlaid sub-cell of said overlaid/underlaid sub-cell structure.

10. The base station controller of claim 1, wherein said channel threshold is based on the number of traffic channels associated with only one of said at least two carrier frequencies.

11. The base station controller of claim 1, wherein said channel threshold is based on the number of traffic channels associated with at least two of said at least two carrier frequencies.

12. A telecommunications system for adaptively configuring the structure of a cell within a cellular network, said cell having a plurality of mobile stations located therein, said telecommunications system comprising:

a base transceiver station within said cell in wireless communication with said plurality of mobile stations, said base transceiver station having at least two carrier frequencies associated therewith; and

a base station controller connected to said base transceiver station, said base station controller being adapted to measure a respective distance of each of said mobile stations involved in a call connection within said cell from said base transceiver station, compare each said respective distance to a distance threshold to determine a number of said mobile stations having said respective distance less than or equal to said distance threshold, perform a comparison of said number to a channel threshold and switch between an overlaid/underlaid sub-cell structure having at least one of said at least two carrier frequencies serving only a portion of said cell and a normal cell structure having all of said at least two carrier frequencies serving the entire area of said cell based on the results of said comparison.

13. The telecommunications system of claim 12, wherein said channel threshold is a number of traffic channels in use.

14. The telecommunications system of claim 13, wherein said base station controller is adapted to switch to said overlaid/underlaid sub-cell structure when the results of said comparison indicate that said number of said mobile stations having said respective distance less than or equal to said distance threshold is greater than or equal to said channel threshold.

15. The telecommunications system of claim 12, wherein said channel threshold is a number of traffic channels available.

16. The telecommunications system of claim 15, wherein said base station controller is adapted to switch to said overlaid/underlaid sub-cell structure when the results of said comparison indicate that said number of said mobile stations having said respective distance less than or equal to said distance threshold is less than or equal to said channel threshold.

17. The telecommunications system of claim 12, wherein said base station controller further comprises a timer, said base station controller being adapted to begin measuring each said respective distance upon the expiration of said timer.

18. The telecommunications system of claim 12, wherein each said respective distance is a radius around said base transceiver station, said distance threshold being an additional radius around said base transceiver station.

19. The telecommunications system of claim 12, wherein each said respective distance is a specific distance from said base transceiver station, said distance threshold being a radius around said base transceiver station.

20. The telecommunications system of claim 12, wherein each said respective distance is a specific distance from said base transceiver station, said distance threshold being a function describing the shape of an overlaid sub-cell of said overlaid/underlaid sub-cell structure.

21. The telecommunications system of claim 12, wherein said base transceiver station has at least two transceiver units associated therewith, each of said at least two transceiver units having a respective one of said at least two carrier frequencies associated therewith.

22. The telecommunications system of claim 21, wherein said base station controller is adapted to switch to said overlaid/underlaid sub-cell structure by reducing the power to at least one of said at least two transceiver units.

23. A method for adaptively configuring the structure of a cell served by a base station controller, said cell having a plurality of mobile stations located therein and a base transceiver station associated therewith, said base transceiver station having at least two carrier frequencies associated therewith, said method comprising the steps of:

determining a respective distance of each of said mobile stations involved in a call connection within said cell from said base transceiver station;

comparing each said respective distance to a distance threshold to determine a number of said mobile stations having said respective distance less than or equal to said distance threshold;

performing a comparison of said number to a channel threshold; and

switching between an overlaid/underlaid sub-cell structure having at least one of said at least two carrier frequencies serving only a portion of said cell and a normal cell structure having all of said at least two carrier frequencies serving the entire area of said cell based on said step of performing.

24. The method of claim 23, wherein said channel threshold is a number of traffic channels in use, said step of switching further comprising the step of:

switching to said overlaid/underlaid sub-cell structure when the results of said comparison indicate that said number of said mobile stations having said respective distance less than or equal to said distance threshold is greater than or equal to said channel threshold.

25. The method of claim 23, wherein said channel threshold is a number of traffic channels available, said step of switching further comprising the step of:

switching to said overlaid/underlaid sub-cell structure when the results of said comparison indicate that said number of said mobile stations having said respective distance less than or equal to said distance threshold is less than or equal to said channel threshold.

26. The method of claim 23, further comprising the steps of:

initializing a timer, said step of measuring each said respective distance being performed upon the expiration of said timer.

27. The method of claim 23, wherein said base transceiver station has at least two transceiver units associated therewith, each of said at least two transceiver units having a respective one of said at least two carrier frequencies associated therewith, said step of switching further comprising the step of:

switching to said overlaid/underlaid sub-cell structure by reducing the power to at least one of said at least two transceiver units.