A method for controlling data transmission by a Radio Network Controller, RNC, in a communication system, comprising steps of: obtaining transmission delays and time differences between the RNC and each of a plurality of Node Bs managed by the RNC; configuring an offset of a system frame number, SFN, for each cell of the plurality of Node Bs relative to a Node B frame number, BFN, of the plurality of Node Bs using a reference Node B being one of the plurality of Node Bs, wherein the offset for the each cell is calculated as a time difference between a start time and a time indicated by the SFN for each cell; configuring a common channel for transmitting data from cells of the plurality of Node Bs, the common channel being used to transmit Multicast Broadcast and Multicast Service, MBMS; transmitting configuration parameters for each cell and configuration parameters of the common channel to a Node B of the plurality of Node Bs; and transmitting to a User Equipment, UE, the configuration parameters of the common channel, wherein the configuration parameters for each cell include the offset for each cell and enable the UE to determine a start time in relation to a reference frame, the method being characterized in that the configuration parameters of the common channel include a frame offset and a chip offset which are determined by a CHoff and a Soff, wherein the CHoff indicates a time difference between channel frame number, CFN, of different Multicast Broadcast and Multicast Service, MBMS, transmission channels and each of SFN for each cell, and wherein the Soff indicates a time difference between a CFN of the common channel and each of the SFN for each cell within one frame. obtaining transmission delays and time differences between the RNC and each of a plurality of Node Bs managed by the RNC; configuring an offset of a system frame number, SFN, for each cell of the plurality of Node Bs relative to a Node B frame number, BFN, of the plurality of Node Bs using a reference Node B being one of the plurality of Node Bs, wherein the offset for the each cell is calculated as a time difference between a start time and a time indicated by the SFN for each cell; configuring a common channel for transmitting data from cells of the plurality of Node Bs, the common channel being used to transmit Multicast Broadcast and Multicast Service, MBMS; transmitting configuration parameters for each cell and configuration parameters of the common channel to a Node B of the plurality of Node Bs; and transmitting to a User Equipment, UE, the configuration parameters of the common channel, wherein the configuration parameters for each cell include the offset for each cell and enable the UE to determine a start time in relation to a reference frame, the method being characterized in that the configuration parameters of the common channel include a frame offset and a chip offset which are determined by a CHoff and a Soff, wherein the CHoff indicates a time difference between channel frame number, CFN, of different Multicast Broadcast and Multicast Service, MBMS, transmission channels and each of SFN for each cell, and wherein the Soff indicates a time difference between a CFN of the common channel and each of the SFN for each cell within one frame.