FIG. 9A shows another scenario where the child nodes and/or UEs may start a timer, for example, timer Tyyy, based on receiving an Upstream RLF notification. While the timer Tyyy is running, Node A may attempt to recover the upstream link by performing cell selection. In the scenario depicted in FIG. 9, Node A has successfully found a new parent node (Parent node 2) and may initiate the RRC reestablishment procedure. Node A, based on receiving F1-AP* configuration update from the CU of the IAB-donor, may transmit/send Upstream Recovery notification—a notification indicating that the upstream is recovered—to the child IAB-node and/or the UEs. If timer Tyyy has not expired yet, the child IAB-node and/or the UEs that receive the notification may stop timer Tyyy and stay connected with Node A. If the timer expires before receiving Upstream Recovery notification, the child IAB-node and/or the UEs may perform cell selection/RRC reestablishment as shown in FIG. 8. In one embodiment, the timer value/configuration may be pre-configured. In another embodiment, the timer value/configuration may be configured by the parent node (e.g., Parent node 1) via a dedicated signaling or via a broadcast signaling (e.g., system information, such as MIB, SIB1 or any of the other SIBs).
Similar to the previous scenario, in one embodiment, the Upstream RLF notification may be carried by the Adaptation Layer, RLC, MAC, or a physical layer signaling. Additionally, the notifications may be broadcasted via system information (e.g., MIB, SIB1 or any of the other SIBs) or transmitted in a dedicated manner.
