CACHING IN MOBILE NETWORKS

• US 20120300747A1
• Filed: 02/01/2010
• Published: 11/29/2012
• Est. Priority Date: 02/01/2010
• Status: Active Grant

• Current Assignee: Telefonaktiebolaget LM Ericsson
• Original Assignee: Telefonaktiebolaget LM Ericsson
• Inventors: Westberg, Lars, Damola, Ayodele, Hellkvist, Stefan
• Granted Patent: US 9,198,089 B2
• Time in Patent Office: Days
• US Class Current: 370/331
• CPC Class Codes: H04L 65/1016 IP multimedia subsystem [IMS]
• CPC Class Codes: H04L 65/104 in the network
• CPC Class Codes: H04L 65/1069 Session establishment or de-establishment
• CPC Class Codes: H04L 65/611 for multicast or broadcast systems for broadcast or conference H04L12/18; arrangements for broadcast or distribution combined with broadcast H04H20/00; arrangements for broadcast applications with a direct linkage to broadcast information or to broadcast space-time H04H60/00; selective distribution of broadcast services, e.g. multimedia broadcast multicast service [MBMS], H04W4/06
• CPC Class Codes: H04W 36/0011 for data sessions of end-to-end connection
• CPC Class Codes: H04W 36/02 Buffering or recovering information during reselection ; Modification of the traffic flow during hand-off

Abstract

A method and apparatus for handing over a terminal connection. A handover request is sent from a source base station to a target base station. A first control message is also sent from the source base station to a control server, the first control message including a session identifier for identifying the session, and current parameters for the session. If the target base station is associated with a cache storage unit containing the content data, a second control message is sent from the control server to the target base station, the second control message including a content identifier, the session identifier and the current parameters. At the target base station, the content data packets are retrieved from the cache storage unit, and a header of each retrieved content data packet is populated with parameters calculated using the received current parameters and session identifier. The content data packets are then sent from the base station towards the terminal.

Claims

1. A target network element configured to act as a caching server for sending data in a session to a mobile terminal in a packet data network, the target network element comprising:

a communications system, configured to;

receive a handover request from a source network element in the network, the handover request instructing the target network element to continue the session previously handled by the source network element;

receive a control message from a control server, the control message comprising a content identifier for identifying content data packets stored in a cache storage unit associated with the target network element, a session identifier for identifying the session, and initial session state parameters for identifying a current session state in the source network element; and

retrieve the content data packets from the cache storage unit;

a local storage medium operatively connected to the communications system for storing session-independent parameters and the received initial session state parameters; and

a packet header generator operatively connected to the communications system and local storage medium, and configured to populate a header of each retrieved content data packet with header parameters calculated using the session-independent parameters together with the received initial session state parameters and session identifier;

wherein the communications system is further configured to send the content data packets towards the terminal.

2. The target network element of claim 1, wherein the packet header generator is configured to calculate static session-specific parameters from the initial session state parameters received from the control server, save the static session-specific parameters in the local storage medium, and insert the static session-specific parameters into each of the retrieved packets sent towards the terminal in that session.

3. The target network element of claim 1, wherein the packet header generator is configured to calculate dynamic parameters for each retrieved packet using the initial session state parameters received from the control server as a starting point, and insert the dynamic parameters into the retrieved packets.

7. The target network element of claim 1, wherein the target network element is a base station or is associated with a base station via a configured tunnel.

8. The target network element of claim 1, further configured so that, if it receives packets from a control server containing content data packets which are not stored in the cache storage unit, these content data packets are stored in the cache storage unit.

9. The target network element of claim 1, wherein the cache storage unit is included in the target network element.

10. The target network element of claim 1, wherein the data sent to the terminal is streaming data.

11. The target network element of claim 1, wherein the packets are RTP packets.

12. The target network element of claim 1, wherein the packet data network is a 3GPP network, and the target network element is an eNodeB.

4. A source network element configured to act as a caching server for sending data in a session to a mobile terminal in a packet data network, the source network element comprising:

a local storage medium for storing session-independent parameters and current session state parameters;

a communications system operatively connected to the local storage medium and configured to;

retrieve content data packets from a cache storage unit associated with the source network element;

identify that the terminal has moved within range of a target network element in the network;

send a handover request to the target network element, the handover request instructing the target network element to continue the session; and

send a session state message to a control server, the session state message comprising the current session state parameters and a session identifier for identifying the session; and

a packet header generator operatively connected to the communications system and local storage medium, and configured to populate a header of each retrieved content data packet with header parameters calculated using the session-independent parameters and current state parameters;

wherein the communications system is further configured to send the content data packets towards the terminal until handover to the target network element is complete.

5. The source network element of claim 4, wherein the packet header generator is configured to calculate static session-specific parameters, save the static session-specific parameters in the local storage medium, and insert the same static session-specific parameters into each of the retrieved packets sent towards the terminal in that session.

6. The source network element of claim 4, wherein the packet header generator is configured to calculate dynamic parameters for each retrieved packet using the current session state parameters as a starting point, and insert the dynamic parameters into the retrieved packets.

25. The source network element of claim 4, wherein the source network element is a base station or is associated with a base station via a configured tunnel.

26. The source network element of claim 4, further configured so that, if it receives packets from a control server containing content data packets which are not stored in the cache storage unit, these content data packets are stored in the cache storage unit.

27. The source network element of claim 4, wherein the cache storage unit is included in the source network element.

28. The source network element of claim 4, wherein the data sent to the terminal is streaming data.

29. The source network element of claim 4, wherein the packets are RTP packets.

30. The source network element of claim 4, wherein the packet data network is a 3GPP network, and the source network element is an eNodeB.

13. A control server for managing the provision of data in a session to a mobile terminal attached to a network element in a packet data network, comprising:

a communications system, configured to receive a request from the terminal to begin sending content data;

a storage medium containing records of content data cached at cache storage units in the network; and

a controller, operatively connected to the communications system and the storage medium, and configured to;

retrieve the records from the storage medium;

identify the content data requested by the terminal;

determine whether the network element is associated with a cache storage unit containing the content data requested by the terminal; and

if so, instruct the communications system to send a control message towards the network element, the control message comprising a content identifier for identifying the content data in the cache storage unit, a session identifier, and initial parameters for the data stream.

14. The control server of claim 13, wherein the communications system is configured to receive a notification from a target network element in the network that the terminal is now attached to the target network element, and to receive a message including the current session state and current parameters from the first network element;

and wherein the controller is configured to;

retrieve the records from the storage medium;

identify whether the target network element is associated with a cache storage unit containing the content data; and

if so, instruct the communications system to send a control message towards the target network element, the control message comprising the content identifier, current session identifier, and current parameters for the data stream.

15. The control server of claim 14, wherein:

a control cache storage unit comprising the content data is associated with the control server; and

the controller is configured, if the cache storage unit associated with the target network element does not contain the content data, to;

instruct the communications system to retrieve the content data from the control cache storage unit;

populate a header of each packet of the retrieved content data with parameters calculated using the received current parameters and session identifier; and

instruct the communications system to send the content data packets towards the terminal via the target network element.

16. The control server of claim 14, wherein the control cache storage unit is part of the control server.

17. A system for transmitting data through one or more packet data networks, the system comprising a target network element configured to act as a caching server for sending data in a session to a mobile terminal in a packet data network, the target network element comprising:

a communications system, configured to;

receive a handover request from a source network element in the network, the handover request instructing the target network element to continue the session previously handled by the source network element;

receive a control message from a control server, the control message comprising a content identifier for identifying content data packets stored in a cache storage unit associated with the target network element, a session identifier for identifying the session, and initial session state parameters for identifying a current session state in the source network element; and

retrieve the content data packets from the cache storage unit;

a local storage medium operatively connected to the communications system for storing session-independent parameters and the received initial session state parameters; and

a packet header generator operatively connected to the communications system and local storage medium, and configured to populate a header of each retrieved content data packet with header parameters calculated using the session-independent parameters together with the received initial session state parameters and session identifier;

wherein the communications system is further configured to send the content data packets towards the terminal; and

the control server of claim 13.

18. A method of initiating a data transfer session between a network element and a terminal in a packet data network, the network element configured to act as a caching server and associated with a cache storage unit, the method comprising, at the network element:

receiving a control message from a control server, the control message comprising a content identifier for identifying content data packets stored in the cache storage unit, a session identifier for identifying the session, and initial parameters for the session;

retrieving the content data packets from the cache storage unit;

populating a header of each retrieved content data packet with parameters calculated using the received initial parameters and session identifier; and

sending the content data packets from the network element towards the terminal.

20. The method of claim 18, wherein the data sent to the terminal is streaming data.

19. A method of handing over a connection to a terminal from a source network element to a target network element in a packet data network when the source network element is acting as a caching server and sending content data towards the terminal, the method comprising:

sending a handover request from the source network element to the target network element;

sending a first control message from the source network element to a control server, the first control message including a session identifier for identifying the session, and current parameters for the session;

at the control server, identifying whether or not the target network element is associated with a cache storage unit containing the content data;

if the target network element is associated with a cache storage unit containing the content data, sending a second control message from the control server to the target network element, the second control message including a content identifier, the session identifier and the current parameters;

at the target network element, retrieving the content data packets from the cache storage unit;

populating a header of each retrieved content data packet with parameters calculated using the received current parameters and session identifier; and

sending the content data packets from the network element towards the terminal.

21. A non-transitory computer program product comprising code adapted to be executed on a network element in a packet data network, the code operable to:

read a control message received at the network element from a control server, the control message comprising a content identifier for identifying content data packets stored in a cache storage unit associated with the network element, a session identifier for identifying a session, and initial parameters for the session;

retrieve the content data packets from the cache storage unit

populate a header of each retrieved content data packet with parameters calculated using the received initial parameters and session identifier; and

send the content data packets towards a terminal.

22. A non-transitory computer program product comprising code adapted to be executed on a source network element in a packet data network, the code operable to:

retrieve content data from a cache storage unit and send the content data towards a terminal;

identify that the terminal is moving out of range of the source network element;

send a handover request to a target network element;

send a control message to a control server, the control message including a session identifier for identifying the session, and current parameters for the session.

23. A non-transitory computer program product comprising code adapted to be executed on a control server in a packet data network, the code operable to:

read a path switch request to a target network element received from a source network element;

read a first control message received from the source network element, the first control message including a session identifier for identifying a session for transferring content data to a terminal, and current parameters for the session;

identify whether or not the target network element is associated with a cache storage unit containing the content data;

if the target network element is associated with a cache storage unit containing the content data, send a second control message from the control server to the target network element, the second control message including a content identifier, the session identifier and the current parameters.

24. (canceled)