Ciphering method in a mobile communication system supporting a multimedia broadcast/multicast service

• US 20050026607A1
• Filed: 08/02/2004
• Published: 02/03/2005
• Est. Priority Date: 08/02/2003
• Status: Active Grant

• Current Assignee: Samsung Electronics Co. Ltd.
• Original Assignee: Samsung Electronics Co. Ltd.
• Inventors: Choi, Sung-Ho, Hwang, Sung-Oh, Kim, Eun-Jung, Lee, Kook-Heui
• Granted Patent: US 7,526,287 B2
• Time in Patent Office: Days
• US Class Current: 455/428
• CPC Class Codes: H04L 12/189 in combination with wireless systems selective distribution or broadcast in wireless communication networks H04W4/06
• CPC Class Codes: H04L 63/0428 wherein the data content is protected, e.g. by encrypting or encapsulating the payload
• CPC Class Codes: H04L 63/062 for key distribution, e.g. centrally by trusted party cryptographic mechanisms or cryptographic arrangements for key distribution involving a central third party H04L9/0819
• CPC Class Codes: H04L 63/068 using time-dependent keys, e.g. periodically changing keys cryptographic mechanisms or cryptographic arrangements for controlling usage of secret information H04L9/088
• CPC Class Codes: H04L 65/1101 Session protocols
• 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: H04L 65/70 Media network packetisation
• CPC Class Codes: H04W 12/033 of the user plane, e.g. user's traffic
• CPC Class Codes: H04W 12/04 Key management, e.g. using generic bootstrapping architecture [GBA]
• CPC Class Codes: H04W 4/06 Selective distribution of broadcast services, e.g. multimedia broadcast multicast service [MBMS]; Services to user groups; One-way selective calling services
• CPC Class Codes: H04W 76/40 for selective distribution or broadcast

Abstract

A method for ciphering MBMS (Multimedia Broadcast/Multicast Service) data in a wired/wireless communication system is provided. The MBMS service enables the same service or desired services to be provided to a number of users. In the ciphering method, a ciphering key for encoding MBMS data is previously provided to an authorized UE, and the authorized UE is informed of when MBMS data encoded using the ciphering key is to be transmitted, thereby preventing unauthorized UEs from illegally receiving the MBMS service.

Claims

1. A method of transmitting data for a broadcast service from a Core Network (CN) in a mobile communication system including the CN for providing broadcast services, at least one Universal Mobile Telecommunications System (UMTS) Terrestrial Radio Access Network (UTRAN) connected to the CN, and at least one User Equipment (UE) for receiving broadcast services through the UTRAN, the method comprising the steps of:

transmitting a plurality of ciphering keys, which are generated for encoding data for the broadcast service, to the at least one UE;

generating a data frame including data encoded using a ciphering key selected from the plurality of the ciphering keys; and

transmitting a ciphering key indicator of the ciphering key to the at least one UE by incorporating the ciphering key indicator into header information of the data frame.

2. The method according to claim 1, further comprising the step of:

if the ciphering key used to encode the data for the broadcast service is changed, transmitting a ciphering key indicator of a changed ciphering key by incorporating the changed ciphering key indicator into the header information of the data frame.

3. The method according to claim 2, wherein the ciphering key used to encode the data is changed at intervals of a predetermined period.

4. The method according to claim 1, wherein the broadcast service is a Multimedia Broadcast/Multicast Service (MBMS) service.

5. The method according to claim 1, wherein the plurality of ciphering keys are transmitted to the at least one UE through a broadcast service response message, in response to a broadcast service request from the at least one UE.

6. A method of receiving data for a broadcast service by at least one User Equipment (UE) in a mobile communication system including a Core Network (CN) for providing broadcast services, at least one Universal Mobile Telecommunications System (UMTS) Terrestrial Radio Access Network (UTRAN) connected to the CN, and the at least one UE for receiving the broadcast services through the UTRAN, the method comprising the steps of:

requesting the broadcast service from the CN;

receiving a plurality of ciphering keys for encoding data for the broadcast service from the CN, in response to the request;

checking a ciphering key indicator included in header information of a data frame received for the broadcast service; and

decoding data received through the data frame using a ciphering key selected from the plurality of ciphering keys indicated by the ciphering key indicator.

7. The method according to claim 6, wherein the ciphering key indicator included in the header information of the data frame is changed at intervals of a predetermined period.

8. The method according to claim 6, wherein the broadcast service is a Multimedia Broadcast/Multicast Service (MBMS) service.

9. A method of transmitting data for a broadcast service from a Core Network (CN) in a mobile communication system including the CN for providing broadcast services, at least one Universal Mobile Telecommunications System (UMTS) Terrestrial Radio Access Network (UTRAN) connected to the CN, and at least one User Equipment (UE) for receiving the broadcast services through the UTRAN, the method comprising the steps of:

transmitting a plurality of ciphering keys generated for encoding data for the broadcast service to the at least one UE;

transmitting a ciphering key indicator of a ciphering key selected from the plurality of ciphering keys for use in encoding the data to the at least one UE through the UTRAN by incorporating the ciphering key indicator into a message indicating that the broadcast service is to be started; and

transmitting the data for the broadcast service encoded using the ciphering key indicated by the ciphering key indicator to the at least one UE.

10. The method according to claim 9, wherein the message indicating that the broadcast service is to be started is a session start message.

11. The method according to claim 9, further comprising the steps of:

changing the ciphering key when a new session is started; and

transmitting a ciphering key indicator of the changed ciphering key by incorporating the changed ciphering key indicator into a session start message indicating that the new session is started.

12. The method according to claim 9, wherein the broadcast service is a Multimedia Broadcast/Multicast Service (MBMS) service.

13. The method according to claim 9, wherein the plurality of ciphering keys are transmitted through a broadcast service response message, in response to a broadcast service request of the UE.

14. A method of transmitting data for a broadcast service from at least one Universal Mobile Telecommunications System (UMTS) Terrestrial Radio Access Network (UTRAN) in a mobile communication system including a Core Network (CN) for providing broadcast services, the at least one UTRAN connected to the CN, and at least one User Equipment (UE) for receiving the broadcast services through the UTRAN, the method comprising the steps of:

receiving a ciphering key indicator of a ciphering key for encoding the data through a session start message from the CN;

transmitting the ciphering key indicator to the at least one UE by incorporating the ciphering key indicator into a notification message; and

transmitting data for the broadcast service encoded using the ciphering key indicated by the ciphering key indicator to the at least one UE.

15. The method according to claim 14, wherein the broadcast service is a Multimedia Broadcast/Multicast Service (MBMS) service.

16. A method of receiving data for a broadcast service by at least one User Equipment (UE) in a mobile communication system including a Core Network (CN) for providing broadcast services, at least one Universal Mobile Telecommunications System (UMTS) Terrestrial Radio Access Network (UTRAN) connected to the CN, and the at least one UE for receiving the broadcast services through the UTRAN, the method comprising the steps of:

requesting the broadcast service from the CN;

receiving a plurality of ciphering keys for encoding data for the broadcast service from the CN, in response to the request;

receiving a ciphering key indicator of a ciphering key for encoding the data among the plurality of ciphering keys from the UTRAN through a message indicating that the broadcast service is to be started; and

decoding data received from the CN using the ciphering key indicated by the ciphering key indicator.

17. The method according to claim 16, wherein the message indicating that the broadcast service is to be started is a notification message.

18. The method according to claim 16, further comprising the step of:

receiving a new ciphering key indicator through a notification message transmitted from the UTRAN when a new session is started.

19. The method according to claim 16, wherein the broadcast service is a Multimedia Broadcast/Multicast Service (MBMS) service.

20. A method of transmitting data for a broadcast service from a Core Network (CN) in a mobile communication system including the CN for providing broadcast services, at least one Universal Mobile Telecommunications System (UMTS) Terrestrial Radio Access Network (UTRAN) connected to the CN, and at least one User Equipment (UE) for receiving the broadcast services through the UTRAN, the method comprising the steps of:

transmitting a plurality of ciphering keys generated for encoding data for the broadcast service to UEs that have requested the broadcast service;

establishing a Radio Access Bearer (RAB) with the UTRAN;

transmitting a ciphering key indicator of a ciphering key selected from the plurality of ciphering keys for encoding the data by incorporating the ciphering key indicator into a response message associated with the establishment of the RAB; and

transmitting the data for the broadcast service that is encoded using the ciphering key indicated by the ciphering key indicator.

21. The method according to claim 20, further comprising the steps of:

changing the ciphering key when a new session is started; and

transmitting a ciphering key indicator of the changed ciphering key by incorporating the changed ciphering key indicator into a response message associated with an established RAB established when the new session is started.

22. The method according to claim 20, wherein the broadcast service is a Multimedia Broadcast/Multicast Service (MBMS) service.

23. The method according to claim 20, wherein the plurality of ciphering keys are transmitted to the UE through a broadcast service response message, in response to a broadcast service request of the UE.

24. A method of transmitting data for a broadcast service from at least one Universal Mobile Telecommunications System (UMTS) Terrestrial Radio Access Network (UTRAN) in a mobile communication system including a Core Network (CN) for providing broadcast services, the at least one UTRAN connected to the CN, and at least one User Equipment (UE) for receiving the broadcast services through the UTRAN, the method comprising the steps of:

receiving a ciphering key indicator of a ciphering key for encoding the data from the CN through a response message associated with establishment of a Radio Access Bearer (RAB) with the CN;

transmitting the ciphering key indicator to the at least one UE by incorporating the ciphering key indicator into a Radio Bearer (RB) setup request message; and

transmitting the data encoded using the ciphering key indicated by the ciphering key indicator to the at least one UE.

25. The method according to claim 24, wherein the broadcast service is a Multimedia Broadcast/Multicast Service (MBMS) service.

26. A method of receiving data for a broadcast service by at least one User Equipment (UE) in a mobile communication system including a Core Network (CN) for providing broadcast services, at least one Universal Mobile Telecommunications System (UMTS) Terrestrial Radio Access Network (UTRAN) connected to the CN, and the at least one UE for receiving the broadcast services through the UTRAN, the method comprising the steps of:

transmitting a broadcast service request message to the CN;

receiving a plurality of ciphering keys for use in encoding the data from the CN through a broadcast service response message;

receiving a ciphering key indicator of a ciphering key selected from the plurality of ciphering keys for use in encoding the data from the UTRAN through a Radio Bearer (RB) setup request message;

setting up an RB with the UTRAN; and

decoding data received through the UTRAN from the CN using the ciphering key indicated by the ciphering key indicator.

27. The method according to claim 26, further comprising the step of:

receiving a new ciphering key indicator of a ciphering key changed when a new session is started, wherein said new ciphering key indicator is received from the UTRAN through an RB setup request message transmitted from the UTRAN.

28. The method according to claim 26, wherein the broadcast service is a Multimedia Broadcast/Multicast Service (MBMS) service.