A process for synchronization in a communications network comprising at least two buses interconnected by a wireless communications network, each bus being linked to the wireless communications network by a portal. The process comprises the steps of: determining a so-called cycle server portal whose own clock will serve as a reference for the other portals; transmitting, via each portal, a synchronization signal at a predetermined instant with respect to the start of a frame and characteristic of each portal, the frame being defined with respect to each portal's own internal clock, the synchronization signal being achieved via the insertion of a control window; and detecting, via each portal, the control windows of other portals and selecting one of the detected windows for the synchronization of the receiver portal's own clock with the clock of the cycle server portal, the selected window corresponding to a portal whose clock is already synchronized with that of the cycle server portal. The invention also relates to receiver and transmitter apparatuses implementing the process.