A method for synchronizing communication devices comprises receiving, in a communication device (102), a first synchronization signal transmitted from a network apparatus (101). Based on the first synchronization signal, communication device (102) performs a coarse synchronization process. Based on the coarse synchronization process, the communications device (102) transmits a scheduling request message to the network apparatus (101). The communication device (102) receives (306), from the network apparatus (101), a second synchronization signal, together with a scheduling grant, at a predetermined time window with reference to the scheduling request, and transmits (307) data from the communication device (102) to the network apparatus (101), based on the scheduling grant.