Registration of a mobile station in a mobile communications network

• US 7,697,934 B2
• Filed: 01/25/2005
• Issued: 04/13/2010
• Est. Priority Date: 08/02/2004
• Status: Active Grant

• Current Assignee: Telefonaktiebolaget LM Ericsson
• Original Assignee: Telefonaktiebolaget LM Ericsson
• Inventors: Vikberg, Jari Tapio, Nylander, Tomas, Niska, Hakan
• Primary Examiner(s): Lao; Lun-Yi
• Assistant Examiner(s): Shen; Qun
• Application Number:
  US11/573,171
• Publication Number:
  US 20080070574A1
• Time in Patent Office: 1,904 Days
• Field of Search: 455/435.1, 455/435.2, 455/435.3, 4554321-4323, 455436-444
• 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 of registering a mobile station in a telecommunication network having 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, said method comprising the steps of:

receiving by an access network controller in the unlicensed radio access network, a registration request message from the mobile station, wherein the registration request message is received via an access point utilizing an unlicensed radio interface;

creating a mobile context for the mobile station;

setting a value of an access reselection timer, wherein the mobile station is prevented from registering with the unlicensed radio access network before the access reselection timer expires;

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;

starting a context keep-alive timer, wherein a value of the context keep-alive timer is greater than the value of the access reselection 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;

resetting the value of the access reselection timer; and

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

2. The method as recited in claim 1, wherein the mobile context is erased when the context keep-alive timer expires.

3. The method as recited in claim 1, wherein the mobile communication access networks are both unlicensed radio access networks.

4. The method as recited in claim 1, wherein the reset value of the access reselection timer is set by incrementing the value first set.

5. The method as recited in claim 1, wherein the value of the access reselection timer is set and reset according to a scheme of timer values.

6. An access network controller in an unlicensed radio access network for controlling access to the unlicensed radio access network by mobile stations, the access network controller being in communication with a core network portion of a licensed mobile communication network and with at least one access point in the unlicensed radio access network, the access network controller comprising:

a processor;

a memory area accessible by the processor, the memory area containing values of an access reselection timer, a value of a context keep-alive timer, and at least one counter variable; and

communication means for receiving a registration request message from a mobile station via an access point utilizing an unlicensed radio interface;

means for creating a mobile context for the mobile station in response to receiving the registration request message;

means for setting a value of the access reselection timer;

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

communication means for receiving a de-registration message from the mobile station;

means for starting the context keep-alive timer, wherein the value of the context keep-alive timer is greater than the value of the access reselection timer;

communication means for receiving a second registration request message from the mobile station;

means for noting that the mobile context is already created;

means for stopping the context keep-alive timer;

means for resetting the value of the access reselection timer; and

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

7. The access network controller as recited in claim 6, wherein the values of the access reselection timer and the value of the context keep-alive timer are alterable according to or predefined schemes.

8. The access network controller as recited in claim 6, further comprising a network management interface for communicating between the access network controller and an operation and maintenance center.

9. The access network controller as recited in claim 8, wherein the values of the access reselection timer and the value of the context keep-alive timer are alterable by the operation and maintenance center via the network management interface.

10. The access network controller as recited in claim 6, wherein the counter variable points out the position of a current value of the access reselection timer in the memory area.