Method and apparatus, for synchronising communications between a radio access network (RAN) node and a wireless device (WD) provisioned with a set of synchronised communication configurations. The method comprises, after receiving, by the RAN node, a downstream protocol data unit (PDU), selecting a synchronised communication configuration from the set of synchronised communication configurations where each synchronised communication configuration includes a downlink portion governing downlink data transmissions to the WD, an uplink portion governing uplink data transmissions from the WD, and a sidelink portion governing sidelink data transmissions between WDs, respective ones of the set of synchronised communication configurations being associated with a periodic communications synchronisation indicator (PCSI). The method further includes transmitting, by the RAN node to the WD, the PCSI associated with the selected synchronised communication configuration, transmitting, by the RAN node to the WD, at a pre-determined interval following transmission of the PCSI, the downstream PDU in accordance with the downlink portion of the selected synchronised communication configuration, and receiving, by the RAN node, an upstream PDU transmitted by the WD in accordance with the uplink portion of the selected synchronised communication configuration.