Prioritized Random Access During 5G Handover to Reduce Collisions
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Solution Overview
Problem
Existing mobile telecommunication systems face challenges in efficiently managing random access procedures during handover, particularly in 5G networks, leading to increased collisions and access failures due to contention-based access and beam failure recovery, which are not adequately addressed by current 3GPP requirements.
Innovation Solution
Implementing prioritized random access procedures by network nodes and user equipment, where the source gNB indicates the need for special treatment to the target gNB, allowing for high-priority RA parameters such as power ramping step and backoff settings based on UE buffer status, QoS flows, and dedicated capabilities, ensuring efficient handover with reduced collisions and access failures.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If contention-based random access is used during handover, then the random access procedure is simple to implement, but collisions and access failures increase
Solution Approach 1:
The random access procedure is segmented into two distinct types: contention-based random access for normal scenarios and prioritized collision-based random access for handover scenarios. This segmentation allows the system to apply the appropriate access method based on the specific situation, reducing collisions during handover while maintaining implementation simplicity for standard operations.
Solution Approach 2:
The system dynamically selects between contention-based and prioritized collision-based random access procedures based on the handover indication received from the source gNB. This dynamic adaptation enables the network to optimize access performance for handover events while maintaining the simplicity of contention-based access for other scenarios.
2Reliability
If prioritized collision-based random access is implemented, then collisions and access failures are reduced, but the system complexity increases
Solution Approach 1:
The source gNB provides a handover indication to the target gNB in advance, allowing the target gNB to prepare prioritized random access resources and parameters before the UE attempts access. This preliminary action enables the prioritized collision-based random access to function smoothly without requiring complex real-time decision-making during the actual access procedure.
Solution Approach 2:
The source gNB acts as an intermediary by transmitting the handover indication to the target gNB, which contains information about the UE's buffer status, QoS flows, and capabilities. This intermediary communication enables the target gNB to configure appropriate prioritized random access parameters without the UE needing to directly assess network conditions, simplifying the overall system architecture.
3Device complexity
If standard random access parameters are used during handover, then the configuration is simple, but handover performance and latency are degraded
Solution Approach 1:
Different random access parameters are applied locally based on the specific handover scenario. The target gNB configures UE-specific prioritized random access parameters including power ramping step, backoff indicator, and preamble selection based on the UE's buffer status, QoS requirements, and capabilities. This local customization optimizes handover performance for each UE without requiring complex network-wide reconfiguration.
Solution Approach 2:
The system changes key random access parameters dynamically during handover, including power ramping step, backoff indicator, and preamble selection. These parameter changes are tailored to the specific handover scenario and UE characteristics, enabling optimized handover performance while maintaining a relatively simple configuration framework based on existing random access mechanisms.
Data Source
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AI summary
Systems, methods, apparatuses, and computer program products for prioritized random access during handover are provided. One method may include transmitting, by a source network node, a handover request to a target network node. The handover request may include an indication of a recognition of prioritized random access for a user equipment. The method may also include receiving an acknowledgement from the target network node, building a reconfiguration message, for the user equipment, comprising a prioritized set of random access parameters, and transmitting, to the user equipment, the reconfiguration message comprising the prioritized set of random access parameters.