Registration Of A Mobile Station In A Mobile Communications Network

• US 20080070574A1
• Filed: 01/25/2005
• Published: 03/20/2008
• Est. Priority Date: 08/02/2004
• Status: Active Grant

• Current Assignee: Telefonaktiebolaget LM Ericsson
• Original Assignee: Telefonaktiebolaget LM Ericsson
• Inventors: Nylander, Thomas, Vikberg, Jari, Niska, Hakan
• Granted Patent: US 7,697,934 B2
• Time in Patent Office: Days
• US Class Current: 455/435.2
• CPC Class Codes: H04W 36/0033 with transfer of context information
• CPC Class Codes: H04W 36/00837 Determination of triggering parameters for hand-off
• CPC Class Codes: H04W 36/14 Reselecting a network or an air interface
• CPC Class Codes: H04W 36/38 by fixed network equipment
• CPC Class Codes: H04W 76/25 Maintenance of established connections
• CPC Class Codes: H04W 88/06 adapted for operation in multiple networks or having at least two operational modes, e.g. multi-mode terminals

Abstract

The current invention relates to the registration of mobile stations in a mobile communications network. It has particular relevance to handovers and roaming between base stations of an unlicensed radio access network (110) and those of a conventional cellular network (120). As the cells in an unlicensed radio access network have a rather small size, it means that handover potentially can occur far more frequently than for a conventional cellular network. This can result in an undesired ‘ping-pong’ effect, i.e. that the mobile station is switching back and forth between two radio cells too frequently. The current invention reduces this effect by preventing the mobile station to register to the unlicensed radio access network during a modifiable period of time (306).

Claims

1. A method in a telecommunication network of registering a mobile station, the telecommunication network including a core network portion of a licensed mobile communication network and at least two mobile communication access networks, at least one of which is an unlicensed radio access network, the unlicensed radio access network including an access network controller adapted to communicate with the core network portion and that is connected to at least one access point, said access network controller being adapted to exchange messages with the mobile station via an unlicensed radio interface with said access point, said access network controller further being adapted to send a value of an access reselection timer to the mobile station, said timer being adapted to prevent the mobile station from registering to the mobile communication access network before said timer expires, said method comprising the steps of:

receiving by the access network controller a registration request message from the mobile station;

creating a mobile context;

setting a value of the access reselection timer;

sending the value of the access reselection timer to the mobile station in a registration accept message;

receiving a de-registration message from the mobile station;

setting a value of a context keep-alive timer where the value of said timer is greater than the value of the access reselection timer;

starting the context keep-alive timer;

receiving by the access network controller another registration request message from the mobile station;

noting that the mobile context already is created;

stopping the context keep-alive timer;

setting for a second time a value of the access reselection timer; and

sending for a second time the value of the access reselection timer to the mobile station in a registration accept message.

3. The method of claim 1 where the mobile context is erased when the context keep-alive timer expires.

4. The method of claim 1 where said mobile communication access networks are both unlicensed radio access networks.

5. The method of claim 1 where the second time value of the access reselection timer is set by incrementing the current value.

6. The method of claim 1 where the value of the access reselection timer is set according to a scheme of timer values.

9. The access network controller as in claim 6, the memory area is adapted so that the values of the access reselection timer and the value of the context keep-alive timer in any of the schemes can be altered.

11. The access network controller as in claim 6 including a network management interface designed to be connected to an operation and maintenance center.

2. (canceled)

7. (canceled)

8. An access network controller in an unlicensed radio access network said access network controller being adapted to communicate with a core network portion of a licensed mobile communication network and is connected to at least one access point, said access network controller being further adapted to exchange messages with mobile stations communicating via an unlicensed radio interface within said access points, said access network controller comprising:

a processor;

a memory area arranged to be accessible by said processor, said memory area containing at least one scheme including values of an access reselection timer and a context keep-alive timer, the memory area further including at least one counter variable; and

means for;

the access network controller receiving a registration request message from a mobile station;

creating a mobile context;

setting a value of an access reselection timer;

sending the value of the access reselection timer to the mobile station in a registration accept message;

receiving a de-registration message from the mobile station;

setting a value of a context keep-alive timer where the value of said timer is greater than the value of the access reselection timer;

starting a context keep-alive timer;

receiving by the access network controller another registration request message from the mobile station;

noting that the mobile context already is created;

stopping the context keep-alive timer;

setting for a second time a value of the access reselection timer; and

sending for a second time the value of the access reselection timer to the mobile station in a registration accept message.

10. The access network controller as in claim 8 including a memory area adapted so that the values of the access reselection timer and the value of the context keep-alive timer in any of the schemes can be altered from a network management interface.

12. The access network controller as in claim 8, wherein the counter variable is adapted to point out the position of a current value of the access reselection timer in said memory area