Method for performing synchronisation for multicast broadcast services in a wireless access communication network, corresponding multicast broadcast server and base station

1. A method for performing data synchronisation in a wireless access communication network, said data to be synchronised coming from an access network gateway and being sent to at least two base stations, said data being further sent from said base stations to user terminals over an air interface in downlink frames, said method comprising the step of sending a signalling message to said at least two base stations from the access network gateway, said signalling message comprising a set of parameters defining unambiguously position and size of said data in said downlink frames and the structure of said data, and sending said data at the position, size and using the structure prescribed in said signalling message from the access network gateway to said at least two base stations.

2. The method according to claim 1 , wherein said data are broadcast and multicast data, sent to said at least two base stations belonging to a predefined multicast and broadcast services (MBS) zone, said user terminals receiving said broadcast and multicast data simultaneously from said at least two base stations.

3. The method according to claim 1 , wherein said data are comprised in a MBS portion of said downlink frames, said signalling message comprising an indication related to the position and size of said MBS portion in said downlink frames.

4. The method according to claim 3 , wherein the structure of said data comprised in said MBS portion comprises indications on the number and/or size and/or position of bursts in said MBS portion.

5. The method according to claim 4 , wherein said downlink frame has a time and frequency extension, said bursts having a rectangular extension in said time and frequency.

6. The method according to claim 4 , wherein the structure of said data comprised in said MBS portion comprises indications on the number and/or size and/or position of MAC PDUs in said bursts.

7. The method according to claim 1 , wherein said signalling message is sent on a per downlink frame basis between said access network gateway and said base stations.

8. A serve for using in a wireless access communication network comprising an access network gateway and at least two base stations, said server comprising means for sending a signalling message to said at least two base stations, said signalling message comprising a set of parameters defining unambiguously position and size of data in a downlink frame sent between said at least two base stations and a user terminal and the structure of said data and means for sending said data in said downlink frame at the position, size and using the structure prescribed in said signalling message to said at least two base stations.

9. The server according to claim 8 , wherein the server belongs to an access network gateway.

10. A base station for use in a wireless access communication network, said base station comprising: means for receiving a signalling message comprising a set of parameters defining unambiguously position and size of data in a downlink frame sent between said base station and a user terminal and the structure of said data, means for encapsulating data received from an access network gateway in a downlink frame at the position, size and using the structure prescribed in said signalling message, means for forwarding said downlink frame and said encapsulated data towards user terminals.

11. The base station according to claim 10 , wherein said base station is operating in broadcast multicast mode.