Candidate Cell Random Access for Faster Inter-Cell Mobility
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Solution Overview
Problem
Current random access procedures in wireless communication networks face challenges when transitioning between cells, particularly in terms of BWP operation, random access type selection, and triggering mechanisms, leading to increased delays and overhead during inter-cell mobility.
Innovation Solution
A method and apparatus that enable switching of active uplink BWPs and setting appropriate random access types (4-step or 2-step) for candidate cells, along with a mechanism to initiate random access procedures based on link quality evaluation, ensuring timely acquisition of timing advance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If traditional L3-based serving cell changes are performed, then complete layer 1 and layer 2 reset is achieved, but interruption times and delays are increased
Solution Approach 1:
The patent segments the cell change process into two distinct parts: L1/L2 rapid switching for immediate service continuity, and L3 reconfiguration for complete protocol stack reset when needed. This allows the system to choose the appropriate granularity based on requirements, avoiding unnecessary full resets and reducing interruption times.
Solution Approach 2:
The patent implements preliminary configuration of candidate cells with all necessary L1/L2 parameters before handover is needed. This pre-configuration allows the UE to rapidly switch to the target cell without waiting for full L3 reconfiguration, significantly reducing interruption times while maintaining reliability.
2Loss of time
If L1/L2-based rapid cell switching is implemented, then interruption times are reduced, but complete layer 1 and layer 2 reset is not achieved
Solution Approach 1:
The patent makes the cell change mechanism dynamic by allowing selection between L1/L2 rapid switching and L3-based full reconfiguration based on current network conditions and requirements. The system can adaptively choose the appropriate method, providing rapid switching when possible and full reset when reliability demands it.
Solution Approach 2:
The patent creates a universal cell change framework that encompasses both L1/L2 rapid switching and L3-based full reconfiguration as valid options. This multi-functional approach allows the same handover mechanism to serve different reliability and speed requirements, making the system more versatile.
3Adaptability or versatility
If multiple random access types are supported, then adaptability to different scenarios is improved, but device complexity increases
Solution Approach 1:
The patent changes the approach from supporting multiple complex random access procedures to parameterizing a single flexible procedure. By introducing parameters that define different access characteristics, the system achieves adaptability without the complexity of multiple separate procedures, simplifying device implementation.
Data Source
AI summary
A random access apparatus configured in a terminal equipment, includes: a memory; and processor circuitry coupled to the memory and configured to: when the terminal equipment evaluates a serving cell and determines that the serving cell satisfies a first condition or when the terminal equipment receives an MAC (media access control) CE (control element) indicating a candidate cell, initiate a random access procedure on the candidate cell.