Embodiments of a Next Generation Node-B (gNB) and methods of communication are disclosed herein. The gNB may be configured with a gNB central unit (gNB-CU) and a gNB distributed unit (gNB-DU). The gNB-CU may determine a route for delivery of a data packet to a User Equipment (UE) on an integrated access backhaul (IAB) of relays. The gNB may generate a physical layer (PHY) data packet in accordance with a split between functionality of a packet data convergence protocol (PDCP) layer at the gNB-CU and functionality of a radio link control (RLC) layer at the gNB-DU. The PHY data packet may include the data packet, a PDCP header, an adaptation layer header, an RLC header, a medium access control (MAC) header, and a PHY header. The adaptation layer header may indicate one or more relays included in the route.