COMMUNICATIONS SYSTEM

• US 20130035056A1
• Filed: 04/13/2011
• Published: 02/07/2013
• Est. Priority Date: 04/15/2010
• Status: Abandoned Application

• Current Assignee: Lenovo Innovations Ltd Hong Kong (Lenovo Group Ltd.)
• Original Assignee: NEC Corporation
• Inventors: Prasad, Anand Raghawa, Jactat, Caroline
• Application Number:
  US13/641,021
• Publication Number:
  US 20130035056A1
• Time in Patent Office: Days
• US Class Current: 455/404.1
• CPC Class Codes: H04W 12/062 Pre-authentication
• CPC Class Codes: H04W 36/14 Reselecting a network or an air interface
• CPC Class Codes: H04W 4/90 Services for handling of emergency or hazardous situations, e.g. earthquake and tsunami warning systems [ETWS]
• CPC Class Codes: H04W 60/00 Affiliation to network, e.g. registration; Terminating affiliation with the network, e.g. de-registration
• CPC Class Codes: H04W 76/50 for emergency 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

A cellular communications system is provided in which a user device maintains and provides a last non-emergency security context to a core network when moving from a network that provided restricted services to a network that provides unrestricted services. In this way, re-authentication of the user device can be avoided in the network that provided unrestricted services.

Claims

1. A method performed by a mobile communications device, the method comprising:

a first registering step of registering, in a normal service mode, with a first cellular network;

obtaining a non-emergency security context from the first cellular network;

storing the non-emergency security context;

a second registering step of registering, in a limited service mode, with a second cellular network;

obtaining an emergency security context from the second cellular network; and

a third registering step of registering, in the normal service mode, with a third cellular network;

wherein the third registering step includes the step of providing the third cellular network with the non-emergency security context obtained from said first cellular network.

2. A method according to claim 1, wherein said providing step includes said non-emergency security context within a tracking area update request that is transmitted to the third cellular network.

3. A method according to claim 1, wherein said third registering step includes the step of receiving a command from the third cellular network to use the non-emergency security context obtained from the first cellular network.

4. A method according to claim 3, comprising removing the emergency security context upon reception of the network command from the third cellular network to use the non-emergency security context obtained from the first cellular network.

5. A method according to claim 1, wherein the first and third cellular networks are the same cellular network.

20. A computer implementable instructions product comprising computer implementable instructions for causing a programmable computer device to perform the method of claim 1.

6. A method performed by a cellular network, the method comprising:

receiving a registration request from a mobile communications device, the registration request including an emergency security context obtained from a current cellular network to which the mobile device is registered in a limited service mode; and

registering the mobile communications device with the cellular network;

wherein the method further comprises;

receiving a non-emergency security context from the mobile communications device;

detecting the received non-emergency security context from the mobile communications device; and

in response to detecting the received non-emergency security context, registering the mobile communications device without authenticating the mobile communications device if the cellular network has an indicated non-emergency security context.

7. A method according to claim 6, wherein the non-emergency security context is received with the registration request.

8. A method according to claim 6, wherein said registration request comprises a tracking area update request.

9. A method according to claim 6, comprising sending a command to the mobile communications device to use the non-emergency security context received from the mobile communications device.

10. A mobile communications device comprising:

means for registering, in a normal service mode, with a first cellular network;

means for obtaining a non-emergency security context from the first cellular network;

means for storing the non-emergency security context;

means for registering, in a limited service mode, with a second cellular network;

means for obtaining an emergency security context from the second cellular network; and

means for registering, in the normal service mode, with a third cellular network;

wherein the means for registering with a third cellular network includes means for providing the third cellular network with the non-emergency security context obtained from said first cellular network.

11. A device according to claim 10, wherein said providing means is operable to include said non-emergency security context within a tracking area update request that is transmitted to the third cellular network.

12. A device according to claim 10, wherein said means for registering with the third cellular network includes the means for receiving a command from the third cellular network to use the non-emergency security context obtained from the first cellular network.

13. A device according to claim 12, operable to remove the emergency security context upon reception of the network command from the third cellular network to use the non-emergency security context obtained from the first cellular network.

14. A device according to claim 10, wherein the first and third cellular networks are the same cellular network.

15. A communications node of a cellular network comprising:

means for receiving a registration request from a mobile communications device, the registration request including an emergency security context obtained from a current cellular network to which the mobile device is registered in a limited service mode; and

means for registering the mobile communications device with the cellular network;

wherein the communications node further comprises;

means for receiving a non-emergency security context from the mobile communications device;

means for detecting the received non-emergency security context from the mobile communications device; and

means, responsive to the detection of the received non-emergency security context, for registering the mobile communications device without authenticating the mobile communications device if the cellular network has an indicated non-emergency security context.

16. A communications node according to claim 15, operable to receive the non-emergency security context with the registration request.

17. A communications node according to claim 15, wherein said registration request comprises a tracking area update request.

18. A communications node according to claim 15, comprising means for sending a command to the mobile communications device to use the non-emergency security context received from the mobile communications device.

19. A mobile communications device that has a normal operating mode when registered with a cellular network that provides unrestricted access to communication services and a limited service operating mode when registered with a cellular network that provides restricted service to communication services, the mobile communications device comprising a controller which is configured such that when the mobile communications device is roaming from a cellular network that provides restricted access to a cellular network that provides unrestricted access, the mobile communications device transmits a previously obtained non-emergency security context to the cellular network that provides unrestricted access.