Non-Synchronized Random Access Handover Using Pre-Assigned Preambles
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Solution Overview
Problem
Current non-synchronized random access procedures in wireless communication systems, particularly during handover events, require temporary identities and resource allocation processes that increase complexity and latency, and are not optimized for handover scenarios.
Innovation Solution
A one-step non-synchronized random access procedure that directly assigns a C-RNTI and HO-specific preamble sequence, eliminating the need for temporary identities and reducing resource allocation complexity, by dividing preamble sequence space and using pre-known parameters for detection, thereby enabling efficient handover operations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If traditional non-synchronized random access procedure is used during handover, then the procedure can handle unsynchronized uplink transmissions, but the complexity and latency increase due to temporary identity assignment and resource allocation processes
Solution Approach 1:
The source eNB pre-configures the UE with target cell parameters including C-RNTI and HO-specific preamble sequence before handover execution. This preliminary assignment eliminates the need for temporary identity assignment during the actual handover procedure, reducing complexity while ensuring reliable handover execution.
Solution Approach 2:
The patent extracts and removes the temporary identity assignment step from the handover procedure. By using pre-assigned C-RNTI and HO-specific preambles, the complex resource allocation and temporary identity management processes are eliminated, simplifying the overall procedure while maintaining handover reliability.
2Reliability
If traditional non-synchronized random access procedure is used during handover, then the procedure can establish uplink synchronization, but the latency increases due to multiple signaling steps
Solution Approach 1:
The UE receives and stores target cell C-RNTI and HO-specific preamble sequence in advance during the handover preparation phase. This preconfiguration enables the UE to directly transmit the HO-specific preamble upon handover execution, eliminating multiple signaling rounds and reducing handover latency while ensuring synchronization reliability.
Solution Approach 2:
The patent enables the UE to skip intermediate resource allocation steps by directly using pre-assigned resources. The UE can immediately transmit the HO-specific preamble on the random access channel without waiting for dynamic resource allocation, significantly reducing handover latency while maintaining synchronization accuracy.
3Adaptability or versatility
If traditional random access procedure with temporary identities is used, then resource allocation can be managed, but bandwidth and radio resource usage are not optimized
Solution Approach 1:
The source eNB copies and forwards the assigned C-RNTI and preamble sequence from the target eNB to the UE during handover preparation. This copying mechanism enables efficient resource reuse and eliminates the need for new resource allocations at the target cell, optimizing radio resource usage while maintaining allocation flexibility.
Solution Approach 2:
The pre-assigned C-RNTI serves multiple functions: it acts as both the UE's identifier in the source cell and the target cell, and as the identifier used during random access preamble transmission. This multi-functionality reduces signaling overhead and optimizes radio resource efficiency while maintaining resource allocation flexibility.
Data Source
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AI summary
A method is provided including sending a source Node-B a target Node-B cell-specific unique identifier for a user equipment to be handed over to the target Node-B, sending the source Node-B a predetermined access preamble sequence for the user equipment to be handed over to the target Node-B, and in response to receiving the predetermined access preamble sequence from the user equipment, sending the user equipment handover related information in association with the cell-specific unique identifier for handing over to the target Node-B.