CFRA Resource Association for Handover Reliability
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Solution Overview
Problem
In dense urban deployments, contention-free random access (CFRA) resources are scarce due to the need for unique configuration per user equipment (UE), leading to potential resource scarcity and increased latency during handovers between cells controlled by different distributed units.
Innovation Solution
An apparatus and method that involve receiving an identification of a serving network access node and associating a sub-set of contention-free-random-access (CFRA) resources with the identified serving network access node, ensuring that each UE has a dedicated CFRA resource for handover operations without resource sharing across different serving network access nodes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If unique CFRA resources are configured per UE to prevent collisions, then reliability of handover is improved, but resource scarcity worsens in dense urban deployments
Solution Approach 1:
The patent segments CFRA resources by associating different subsets with different serving network access nodes (gNB-DUs). Instead of using a single pool of CFRA resources for all UEs across all nodes, the system divides the resource pool into node-specific subsets, allowing each node to have dedicated resources for its UEs while enabling other nodes to reuse the same physical resources for different UEs.
Solution Approach 2:
The patent applies local quality by making CFRA resource availability dependent on the local context of the serving network access node. Each gNB-DU is assigned specific CFRA resource subsets that are locally optimized for its UEs, while the same physical resources can be simultaneously used by UEs of different serving nodes, effectively creating location-specific resource allocation.
2Productivity
If CFRA resources are shared across multiple UEs, then resource efficiency is improved, but collision probability increases
Solution Approach 1:
The patent introduces the serving network access node identification as an intermediary parameter that mediates between resource sharing and collision avoidance. The association between CFRA resources and serving gNB-DU IDs acts as a virtual intermediary that allows physical resource sharing while maintaining logical separation, preventing collisions through identification-based differentiation rather than physical resource isolation.
3Loss of time
If dedicated CFRA resources are assigned to each UE, then handover latency is reduced, but device complexity increases
Solution Approach 1:
The patent applies preliminary action by pre-associating CFRA resource subsets with serving network access nodes before handover occurs. The gNB-DU ID to CFRA resource subset mappings are established in advance through configuration messages, so that when handover is triggered, the target node can immediately identify and allocate appropriate pre-configured resources without complex real-time calculations.
Data Source
AI summary
An apparatus (DU) comprising: means for receiving an identification of a serving network access node; and means for associating a sub-set of contention-free-random-access (CFRA) resources with the identified serving network access node. An apparatus (CU) comprising: means for sending a first message comprising an identification of a serving network access node (sDU) to enable association of a sub-set of contention-free-random-access (CFRA) resources with the identified serving network access node (sDU); and means for receiving, in reply, a second message specifying the association of the sub-set of contention-free-random-access (CFRA) resources with the identified serving network access node (sDU).