Dual Connectivity Handover Using Reserved Random Access Preambles
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Solution Overview
Problem
Current wireless communication systems face challenges in efficiently handling handovers between serving nodes in dual connectivity scenarios, particularly due to bottlenecks in the handling and distribution of random access channel preambles, which can lead to delays and increased risk of radio link failure during handovers.
Innovation Solution
The method involves reserving a group of random access channel preambles at a serving node and allocating them to a target serving node during handovers, allowing for seamless transitions without requiring further communication with the serving node, thereby speeding up the handover process and reducing signaling overhead.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If random access channel preambles are distributed dynamically during handover, then the serving node can maintain control over resource allocation, but the handover process experiences delays due to additional signaling communication
Solution Approach 1:
The source serving node pre-allocates and reserves a group of random access channel preambles before handover occurs. This preliminary action eliminates the need for real-time preamble allocation during handover, reducing signaling overhead and accelerating the handover process. The pre-allocated preambles are transmitted to the target serving node in advance, enabling immediate use during handover execution.
2Loss of time
If random access channel preambles are pre-allocated at the source serving node, then handover delays are reduced, but the serving node loses dynamic control over preamble distribution
Solution Approach 1:
The source serving node performs preliminary allocation of random access channel preambles from an available pool, reserving them for upcoming handovers. This reduces handover delay while maintaining controlled flexibility through the pre-selection process.
Solution Approach 2:
A designated group of preambles acts as an intermediary resource between the source and target serving nodes. This intermediary pool maintains resource availability and control while enabling fast handover execution without real-time negotiation.
3Reliability
If the source serving node waits for confirmation from the target serving node before allocating preambles, then resource conflicts are avoided, but handover reliability decreases due to increased risk of radio link failure
Solution Approach 1:
The source serving node pre-allocates preambles and transmits them to the target serving node before handover execution. The target node acknowledges receipt, ensuring resource availability is confirmed in advance, which improves reliability while maintaining efficiency.
Solution Approach 2:
The handover process skips the real-time preamble allocation step by using pre-allocated preambles. This rushing through of the allocation phase reduces the window for potential failures while maintaining resource conflict avoidance through prior coordination.
Data Source
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AI summary
A method comprising: receiving at a source serving node (505) an identifier associated with a group of random access channel preambles for allocation by the source serving node (505), the group of random access channel preambles having been reserved at a serving node (503) from available random access channel preambles for the serving node (503); allocating at least one from the group of random access channel preambles, in response to determining a handover from the source serving node (505) to a target serving node (507); and transmitting (515) a message to the target serving node (507), the message comprising the at least one from the group of random access channel preambles.