Uplink Timing Alignment for Ultra-Reliable Multi-Cell Handover
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Solution Overview
Problem
Current wireless communication systems face challenges in ensuring reliable handovers between master and slave cells due to differences in propagation delays, leading to potential interference and reduced communication efficiency.
Innovation Solution
The method involves a slave cell receiving a propagation delay difference from a master cell, determining adjacent buffer gap resources, and reserving both uplink and buffer gap resources to accommodate uplink transmissions based on the master cell's timing advance, ensuring coordinated multi-cell communication and reducing interference.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a user device performs uplink transmission to both master cell and slave cell using timing advance associated with master cell, then handover reliability is improved, but transmission timing alignment deteriorates due to propagation delay differences
Solution Approach 1:
The slave cell determines buffer gap resources in advance based on the propagation delay difference received from the master cell. This preliminary determination of buffer timing allows the slave cell to accommodate the timing advance used by the user device for master cell transmission, ensuring proper reception timing without requiring separate timing advance for slave cell
Solution Approach 2:
The buffer gap acts as an intermediary mechanism between the master cell's timing advance and the slave cell's reception timing. By introducing this intermediate buffer period, the system reconciles the timing mismatch caused by different propagation delays, allowing the user device to use a single timing advance while maintaining synchronization at both cells
2Object-affected harmful factors
If buffer gap resources are reserved to accommodate timing differences, then interference is reduced, but resource efficiency deteriorates due to additional reserved resources
Solution Approach 1:
The slave cell determines the buffer gap resources by changing the timing parameter based on the propagation delay difference. This dynamic adjustment of buffer timing parameters allows the system to minimize the buffer gap size while still preventing interference, thereby optimizing resource efficiency rather than using a fixed conservative buffer
3Reliability
If propagation delay difference is determined and communicated between cells, then transmission coordination is improved, but system complexity deteriorates due to additional signaling
Solution Approach 1:
The propagation delay difference is determined in advance during the handover preparation phase, before the actual handover execution. This preliminary determination and communication of the delay difference allows both cells to pre-coordinate their resource allocation and buffer timing, simplifying the actual handover execution and reducing real-time complexity
Data Source
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AI summary
A technique may include receiving, by a user device in a wireless network, an indication of a set of uplink time-frequency resources to be used for an uplink transmission from the user device to both a master cell and a slave cell, determining, by the user device, a timing advance associated with the master cell, and performing a single transmission, by the user device, of a block of data to both of the master cell and the slave cell via the set of uplink time-frequency resources using the timing advance associated with the master cell.