METHOD AND DEVICES FOR EFFICIENT DATA TRANSMISSION LINK CONTROL IN MOBILE MULTICAST COMMUNICATION SYSTEMS

摘要

A method for a data transmission with ARQ protocol using multicast groups such as GSM, GPRS or UMTS in a mobile communication system is described. Data is transmitted in data blocks (PDU) from a transmitter (T) to a plurality of receivers (R 1 -RM), said data blocks (PDU) being identifiable by an identification (e.g. a sequence number). The receivers (R 1 -RM) send status indications to the transmitter (T) whether a data block (PDU) is correctly received. The transmitter (T) is adapted to perform retransmissions according to the status indications and has a transmission window comprising the transmission status for the data blocks (PDU) according to their identification. In the method, a synchronization to the transmitter (T) is performed for at least one first of said receivers (Ri), wherein a range of identifications of transmitted data block (PDU) is selected in said synchronization. The transmitter (T) deletes the transmission status for the selected range of identifications from the transmitter window and the first receiver (Ri) stops sending status indications for the data blocks (PDU) corresponding to the selected range of identifications. In addition, a transmitter and a computer program implementing the method are described. As an example the transmitter can be a RNC extending the RLC and MAC-HSPDA protocols standardized by 3GPP for obtaining efficient and reliable point-to-multipoint radio links.