Method of determining the validity of service announcements

1. A method of determining validity of service announcements in a cellular mobile network, wherein a multimedia broadcast/multicast service is provided and a service area is defined by the availability of a specific broadcast/multicast service which availability is announced in each cell, comprising:

generating a service announcement area identification which is the same for cells with identical service announcements; and

checking by a user entity upon arrival in a new cell which service announcement is valid by receiving the service announcement area identification; and wherein

the user entity receives a service announcement in the new cell if the received service announcement area identification is new to the user entity.

2. The method according to claim 1 , wherein the service announcement area identification is included in System Information Block messages which are transmitted in 3 rd Generation cells.

3. A method of determining validity of service announcements in a cellular mobile network, wherein a multimedia broadcast/multicast service is provided, a service area is defined by the availability of a specific broadcast/multicast service which availability is announced in each cell and there are service-specific announcements which are the same for the whole service area, comprising:

generating a service announcement area identification which is the same for cells with identical service announcements; and

checking by a user entity upon arrival in a new cell which service announcement is valid by receiving the service announcement area identification; and wherein

the user entity receives a service announcement in the new cell if the received service announcement area identification is new to the user entity.

4. The method according to claim 3 , wherein:

the service announcement area identification is included in System Information Block messages which are transmitted in 3 rd Generation cells.

5. A method of determining the validity of service announcements in a cellular mobile network, wherein a multimedia broadcast/multicast service is provided, a service area is defined by the availability of a specific broadcast/multicast service which availability is announced in each cell, a local area is defined as an area where the service content is the same, a service area comprises at least one local area, and there are content-specific announcements which are different for different local areas, comprising:

generating a service announcement area identification which is the same for cells with identical service announcements; and

checking by a user entity upon arrival in a new cell which service announcement is valid by receiving the service announcement area identification; and wherein

the user entity receives a service announcement in the new cell if the received service announcement area identification is new to the user entity.

6. The method according to claim 5 , wherein:

the service announcement area identification is included in System Information Block messages which are transmitted in 3 rd Generation cells.

7. A system for determining the validity of service announcements in a cellular mobile network, wherein the network provides a multimedia broadcast/multicast service, comprising:

service areas which are defined by availability of a specific respectively provided broadcast/multicast service;

means adapted to announce the availability in each cell; and

means adapted to generate a service announcement area identification which is the same for cells with identically provided and announced services; and wherein

the means adapted to generate the service announcement area identification includes identical System Information Block messages which are transmitted in 3 rd Generation cells.

8. The system according to claim 7 , wherein:

the means adapted to announce the availability of a service are provided for a whole service area.

9. The system according to claim 7 , wherein:

the system further comprises local areas which are defined as an area where service content is identical and at least one local area is comprised in a service area, and the means adapted to announce the availability of a service are different for different local areas.

10. A user entity for determining the validity of service announcements in a cellular mobile network, comprising:

means adapted to check, upon arrival in a new cell, which service announcement of a multimedia broadcast/multicast service providing system is valid; and

means adapted to receive a service announcement area identification which is identical for cells with identical service announcements and means adapted to receive a service announcement in the new cell if the received service announcement area identification is new to the user entity.

11. The user entity according to claim 10 , comprising:

means adapted to receive the service announcement area identification included in System Information Block messages which are transmitted in 3 rd Generation cells.

12. The user entity according to claim 10 , comprising:

means adapted to process service-specific announcements which are identical for a whole service area being defined by the availability of a specific broadcast/multicast service which availability is announced in each cell.

13. The user entity according to claim 10 , comprising:

means adapted to process content-specific announcements which are different for different local areas being respectively defined as an area where the service content is identical, wherein a service area comprises at least one local area and the service area is defined by availability of a specific broadcast/multicast service which availability is announced in each cell.

14. A method of determining validity of service announcements in a cellular mobile network, wherein a multimedia broadcast/multicast service is provided and a service area is defined by the availability of a specific broadcast/multicast service which availability is announced in each cell, comprising:

generating a service announcement area identification which is identical for cells with identical service announcements;

checking by a user entity upon arrival in a new cell which service announcement is valid by receiving the service announcement area identification; and wherein

the user entity retrieves the availability of a specific broadcast/multicast service from a memory if the received service announcement area identification is known to the user entity from within an already visited cell.

15. A method of determining validity of service announcements in a cellular mobile network, wherein a multimedia broadcast/multicast service is provided, a service area is defined by the availability of a specific broadcast/multicast service which availability is announced in each cell, and there are service-specific announcements which are identical for the whole service area comprising:

generating a service announcement area identification which is identical for cells with identical service announcements; and

checking by a user entity upon arrival in a new cell which service announcement is valid by receiving the service announcement area identification; and wherein

the user entity retrieves an availability of a specific broadcast/multicast service from a memory if the received service announcement area identification is already known to the user entity from within a previously visited cell.

16. A method of determining the validity of service announcements in a cellular mobile network, wherein a multimedia broadcast/multicast service is provided, a service area is defined by the availability of a specific broadcast/multicast service which availability is announced in each cell, a local area is defined as an area where the service content is identical, wherein a service area comprises at least one local area and there are content-specific announcements which are different for different local areas, comprising:

generating a service announcement area identification which is identical for cells with identical service announcements; and

checking by a user entity upon arrival in a new cell which service announcement is valid by receiving the service announcement area identification; and wherein

the user entity retrieves an availability of a specific broadcast/multicast service from a memory if the received service announcement area identification is already known to the user entity from within a previously visited cell.

17. A user entity for determining the validity of service announcements in a cellular mobile network, comprising

means adapted to check, upon arrival in a new cell, which service announcement of a multimedia broadcast/multicast service providing system is valid;

means adapted to receive a service announcement area identification which is identical for cells with identical service announcements; and

a memory and means adapted to retrieve an availability of a specific broadcast/multicast service from the memory if the received service announcement area identification is known to the user entity from within an already visited cell.