Methods and apparatus for performing dual active protocol stack handover in integrated access backhaul in wireless communication systems

A relay device configured for performing handover from a first node to a second node in a wireless network, the relay device comprising a processor and a transmitter/receiver unit configured to:

• receive information indicating a handover command;
• determine, a channel quality for a first link between the relay device and the first node, and a channel quality for a second link between the relay device and the second node;
• during the handover, send uplink data via the first link and the second link based on any of:
• (1) the determined channel quality for the first link, (2) the determined channel quality for the second link, and/or (3) an uplink data buffer occupancy at the relay device;
• and
• send, to a wireless transmit/receive unit (WTRU) served by the relay device via a third link, information indicating a completion of the handover of the relay device from the first node to the second node.

The relay device according to claim 11, wherein the transmitter/receiver unit is further configured:

• receive information indicating a handover configuration;
• send a request establish the second link between the relay device and the second node using the received information indicating the handover configuration
• wherein the handover configuration indicates one or more backhaul (BH) radio link control (RLC) channels associated with the first link, and further comprising sending the uplink data via the one or more BH RLC channels associated with the first link, and/or
• wherein the handover configuration indicates one or more BH RLC channels associated with the second link, and further comprising sending the uplink data via the one or more BH RLC channels associated with the second link.

The relay device according to WTRU of claim 11, wherein:

• the transmitter/receiver unit is further configured:
• receive a downlink packet via the first link or the second link;
• wherein the processor is further configured to:
• determine a routing identifier associated with the downlink packet;
• and
• determine, on condition that the routing identifier associated with the downlink packet corresponds to any of a first address associated with the first node and a second address associated with the second node, that the downlink packet is addressed to the relay device.