Mobility management entity tracking for group mobility in wireless communication network

1. A method for updating a mobile device with mobility management entity (MME) identification information during group mobility in a wireless communication network, the method comprising:

camping on a mobile relay node (RN) that supports group mobility in the wireless communication network,

the mobile RN connected to a first base station supported by a first MME;

receiving, at the mobile device, an identity associated with a second MME when the mobile RN connects to a second base station served by the second MME,

the identity of the second MME received while the mobile device is camped on the mobile RN without the mobile device first sending a registration message to the second MME.

2. The method of claim 1 further comprising:

decamping the mobile device from the mobile RN and camping the mobile device on a new base station,

transmitting, from the mobile device, the identity associated with the second MME to the new base station.

3. The method of claim 1 further comprising

camping on the mobile RN for a continuous time interval;

receiving, at the mobile device, the identity associated with the first MME and the identity associated with the second MME during the continuous time interval.

4. The method of claim 1 further comprising:

storing the identity associated with the first MME;

updating the identity associated with the first MME with the identity associated with the second MME after receipt of the identity associated with the second MME.

5. The method of claim 1 , receiving the first updated mobility management entity (MME) identification information in a non-access stratum message.

6. The method of claim 1 , receiving the identity associated with the second MME in a system message broadcast by the mobile RN.

7. The method of claim 1 further comprising operating the mobile device in a radio resource control (RRC) connected mode, wherein the identity associated with the second MME is received in a radio resource control (RRC) message from the mobile RN.

8. The method of claim 1 , sending a first registration message, to the first MME via the mobile RN, the first registration message for bounding a context of the mobile device with a context of the mobile RN.

9. A method in a mobile device coupled to a mobile relay node that supports group mobility, the method comprising:

connecting the mobile device to a wireless communication network via a mobile relay node (RN) that supports group mobility;

sending a registration message to an MME via the mobile RN, the MME associated with a first base station to which the mobile RN is connected;

in response to sending the registration message, receiving an indication to use mobile RN specific mobility management entity (MME) identification information in future registration messages,

the mobile RN specific MME identification information is uniquely associated with the mobile RN;

connecting the mobile device to the wireless communication network via a new base station other than the mobile RN; and

communicating, from the mobile device, the mobile RN specific MME identification information to the new base station.

10. The method of claim 9 , communicating the mobile RN specific MME identification information to the new base station in a radio resource control (RRC) Connection Setup Complete message carrying a registration message.

11. The method of claim 9 , communicating the mobile RN specific MME identification information to an MME serving the new base station in a registration message.

12. A method in a mobility management entity (MME) in a wireless communication network, the method comprising:

receiving mobile relay node (RN) specific MME identification information from a mobile device camped on a base station served by the MME,

the mobile RN specific MME identification information is uniquely associated with a mobile RN that served the mobile device before the mobile device camped on the base station served by the MME;

obtaining mobile device context information from another MME that served the mobile RN with which the mobile RN specific MME identification information is associated,

wherein the context information for the mobile device is bound on the another MME with context information for the mobile RN with which the mobile RN specific MME identification information is uniquely associated.

13. The method of claim 12 , wherein the mobile device context information includes network capability and service subscription information for the mobile device.

14. The method of claim 12 , wherein the context of the mobile device includes authentication and security information of the mobile device.