Selecting a communications channel for a mobile station based on handover intensity

• US 5,822,696 A
• Filed: 10/24/1996
• Issued: 10/13/1998
• Est. Priority Date: 10/24/1996
• Status: Expired due to Term

• Current Assignee: Telefonaktiebolaget LM Ericsson
• Original Assignee: Telefonaktiebolaget LM Ericsson
• Inventors: Bergkvist, Bengt Gunnar
• Primary Examiner(s): Eisenzopf, Reinhard J.
• Assistant Examiner(s): Aoki, Makoto
• Application Number:
  US08/736,196
• Time in Patent Office: 719 Days
• Field of Search: 455/441, 455/444, 455/437
• US Class Current: 455/436
• CPC Class Codes: H04W 36/04 Reselecting a cell layer in multi-layered cells

Abstract

A threshold limit representing the number of handovers allowed to be performed by a mobile station within a predetermined period of time is assigned to a serving mobile network. In case a fast moving mobile station exceeds the prescribed number of handovers, a cell selection in accordance with the hierarchical cell location method is overruled. Instead, a cell selection in accordance with the normal cell location method is implemented to reduce the number of future handovers by the fast moving mobile station.

Claims

1. A method for selecting a new cell channel for a mobile station traveling out of a cell area and traveling into a geographic area concurrently covered by a microcell and a macrocell within a mobile telecommunications network, wherein said mobile station can be assigned a traffic channel within either said macrocell or said microcell in accordance with a hierarchical cell selection procedure or another cell selection procedure, said method comprising the steps of:

determining a need to handover said mobile station to one of said microcell or macrocell;

determining an actual number of handovers that occurred within a particular period of time within said mobile telecommunications network;

determining whether the actual number of handovers performed by said mobile station within said particular period of time is less than a threshold number of handovers; and

in response to an affirmative determination,

performing said hierarchical cell selection procedure to handover said mobile station to either said macrocell or said microcell;

otherwise;

performing said another cell selection procedure to handover said mobile station to either said macrocell or said microcell based on a highest signal strength detected by said mobile station.

2. The method of claim 1 wherein said step of performing said hierarchical cell selection procedure comprises a step of selecting the traffic channel associated with said microcell.

3. The method of claim 1 wherein said step of performing said another cell selection procedure comprises a step of selecting the traffic channel associated with said macrocell.

4. The method of claim 1 wherein said step of performing said hierarchical cell selection procedure further comprises the steps of:

maintaining data representing said handover being performed to said selected cell; and

communicating said data to a telecommunications node associated with said selected cell.

5. The method of claim 4 wherein said telecommunications node comprises a base station controller (BSC) associated with said selected cell.

6. The method of claim 4 wherein said data further includes a time stamp indicating the time said handover was performed.

7. The method of claim 4 wherein said step of communicating said data utilizes handover signals.

8. A method for handing over a mobile station from a first geographic area to a second geographic area within a mobile telecommunications network, said second geographic area being served by a plurality of cells including a microcell and a macrocell, said method comprising the steps of:

determining a number of handovers performed by said mobile station within a particular period of time;

evaluating whether said determined number of performed handovers exceeds a threshold number of handovers;

if yes,

handing over said mobile station to a particular one of said plurality of cells using a first cell selection procedure based on signal strength detected by said mobile station;

otherwise,

handing over said mobile station to a particular one of said plurality of cells using a second cell selection procedure based on a hierarchical procedure.

9. The method of claim 8 wherein said second cell selection procedure includes handing over said mobile station to said microcell.

10. The method of claim 9 wherein said step of handing over said mobile station to said microcell further comprises the steps of:

generating data representing said handover to said microcell; and

communicating said data to a telecommunications node serving said microcell.

11. The method of claim 10 wherein said data includes a time stamp indicating the time of said handover.

12. The method of claim 8 wherein said step of handing over said mobile station to said particular one of said plurality of cells using said first cell selection procedure comprises a step of handing over said mobile station to said macrocell.

13. The method of claim 12 wherein said step of handing over said mobile station to said macrocell further comprises the step of initializing data representing a number of handovers performed by said mobile station.

14. A system for handing over a mobile station from a first geographic area to a second geographic area within a mobile telecommunications network, said second geographic area being served by a plurality of cells including a microcell and a macrocell, said system, comprising:

a processor for determining a number of handovers performed by said mobile station within a particular period of time;

said processor further includes evaluating whether said determined number of performed handovers exceeds a threshold number of handovers;

if yes,

a module for handing over said mobile station to particular one of said plurality of cells utilizing a first cell selection method based on signal strength detected by said mobile station;

otherwise,

said module for handing over said mobile station to particular one of said plurality of cells utilizing a second cell selection method based on a hierarchical procedure.

15. The system of claim 14 wherein said processor includes an application module.

16. The system of claim 14 wherein said module includes a base station controller.

17. The system of claim 14 wherein said particular one of said plurality of cells selected using said first cell selection method comprises said macrocell.

18. The system of claim 14 wherein said second cell selection method comprises a hierarchical cell selection method wherein said mobile station is handed over to said microcell.

19. The system of claim 18 further comprising:

a generator for generating data representing said handover to said microcell; and

a transmitter for communicating said data with said telecommunications node associated with said microcell.

20. The system of claim 19 wherein said system further includes a telecommunications node having a base station controller serving said microcell.

21. The system of claim 19 wherein said data includes a time stamp indicating the time of said handover.