IAB Bearer Management via Segmented Path Determination

The patent segments the bearer management process into distinct phases: path determination phase (where the CU determines the forwarding path through IAB nodes) and configuration phase (where DRB setup request messages are transmitted to each node). This segmentation allows complex bearer management to be broken down into manageable, standardized steps that improve reliability without overwhelming system complexity.

The patent implements preliminary action by determining the forwarding path through IAB nodes before establishing the data radio bearers. The CU identifies the complete path from the serving cell to the donor cell in advance, then uses this predetermined path information to configure DRBs at each node along the path. This preliminary path determination ensures reliable bearer management while simplifying the actual DRB establishment process.

The CU performs preliminary determination of the forwarding path through IAB nodes before transmitting DRB setup request messages. By pre-identifying which nodes require configuration and what configuration parameters are needed, the system achieves accurate bearer configuration while minimizing the time required for signaling exchanges.

The patent implements a feedback mechanism where each node responds to DRB setup request messages with confirmation of successful configuration or reports of failures. The CU uses this feedback information to determine which QoS flows and UE data bearers were successfully established and which require retry or alternative handling, thereby improving overall configuration accuracy without requiring excessive reconfiguration time.

The patent segments latency management into node-specific discard mechanisms. Each IAB node along the forwarding path implements its own discard mechanism based on the total latency requirement and its position in the multi-hop relay system. This segmentation allows the complex overall latency management to be distributed across simpler, identical mechanisms at each node, improving QoS compliance without centralizing complexity.

The patent uses parameter changes by configuring discard timers at each IAB node based on the remaining latency budget. As data packets traverse the multi-hop relay system, each node adjusts its discard timer parameter according to the residual latency allowance, ensuring that packets meeting QoS requirements are forwarded while exceeding packets are discarded. This parameter-based approach manages latency complexity through standardized, adjustable thresholds rather than complex active management.