Downlink (DL) transmission timing of integrated access and backhaul (IAB) node

An apparatus comprising:

• one or more processors configured to cause a radio access node to:
• determine a first reference timing of a first communication connection between the radio access node and a second, parent radio access node;
• determine a second reference timing of a second communication connection between the radio access node and a third, child radio access node;
• generate a request for the child radio access node to perform a timing advance adjustment based on the first and second reference timings, so that an uplink receive signal transmitted by the child radio access node arrives at the same time at the radio access node as a downlink transmission signal transmitted by the radio access node arrives at the child radio access node in case of frequency division multiplexed signals;
• and
• apply different analog spatial beamformers for the receive signals transmitted by the parent radio access node and the child radio access node.

A non-transitory memory medium storing program instructions, wherein the instructions, when executed by one or more processors, cause a radio access node to:

• determine a first reference timing of a first communication connection between the radio access node and a second, parent radio access node;
• determine a second reference timing of a second communication connection between the radio access node and a third, child radio access node;
• generate a request for the child radio access node to perform a timing advance adjustment based on the first and second reference timings, so that an uplink receive signal transmitted by the child radio access node arrives at the same time at the radio access node as a downlink receive signal transmitted by the parent radio access node arrives at the radio access node in case of frequency division multiplexed signals;
• and
• apply different analog spatial beamformers for the receive signals transmitted by the parent radio access node and the child radio access node.