Terminal Early Synchronization for Low-Latency Cell Handover
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Solution Overview
Problem
Conventional communication systems face challenges in maintaining communication quality and reducing handover latency during cell transitions, particularly in scenarios involving device-to-device, machine-to-machine, and vehicle-to-everything communications.
Innovation Solution
Implementing an early synchronization process for terminal devices, where the transmitting power is determined based on first information, allowing for controlled power ramping during random access processes to candidate cells, thereby reducing the need for additional random access procedures and improving communication quality.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of time
If conventional handover process is used, then communication continuity is maintained, but handover latency increases and communication quality deteriorates
Solution Approach 1:
The patent implements early synchronization processes before actual handover occurs. The terminal device performs synchronization with the target cell in advance, determines appropriate transmitting power based on first information (such as downlink signal quality measurements), and prepares uplink timing advance values beforehand. This preliminary action eliminates the need for random access procedures during handover, significantly reducing handover latency while ensuring communication quality through optimized power control.
2Reliability
If transmitting power is increased for synchronization signals, then synchronization success rate improves, but energy consumption increases
Solution Approach 1:
The patent dynamically adjusts transmitting power parameters based on measured downlink signal quality (first information). Instead of using fixed high power for all synchronization transmissions, the terminal device calculates appropriate power levels by measuring reference signal received power (RSRP) or reference signal received quality (RSRQ) of the target cell and applying power offset values. This parameter adaptation ensures sufficient synchronization success rate while minimizing unnecessary energy consumption.
Solution Approach 2:
The terminal device autonomously determines its transmitting power for synchronization signals by measuring the downlink signal quality of the target cell and calculating the required power level based on predefined relationships between downlink quality and uplink power requirements. This self-service mechanism eliminates the need for network device intervention in power determination, reducing signaling overhead and enabling efficient energy utilization.
3Reliability
If additional random access procedures are performed during handover, then uplink synchronization is achieved, but handover latency increases
Solution Approach 1:
The patent performs uplink synchronization as a preliminary action before handover execution. The terminal device determines transmitting power based on measured downlink signal quality and transmits synchronization signals to the target cell in advance, obtaining timing advance values and confirming uplink synchronization status. By completing this synchronization beforehand, the patent eliminates the need for additional random access procedures during the actual handover process, significantly reducing handover latency while ensuring reliable uplink synchronization.
Data Source
AI summary
A terminal device is provided. The terminal device includes a memory and a processor, where the memory is configured to store a computer program, and the processor is configured to execute the computer program stored in the memory to cause the terminal device to perform an operation of: initiating an early synchronization process, where a transmitting power corresponding to the early synchronization process is determined based on first information.