Uplink Synchronization via Downlink Timing Differences
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Solution Overview
Problem
Existing wireless communication systems face challenges in efficiently determining uplink synchronization information for terminal devices, leading to high uplink resource overheads and prolonged transmission delays due to the inflexibility of the random access procedure.
Innovation Solution
A method where a terminal device, while being in uplink synchronization with a first transmission-reception point (TRP), determines uplink synchronization information for a second TRP using information such as uplink synchronization information for the first TRP, downlink time difference of arrival, and transmission timing difference between the TRPs, without initiating a random access procedure to the second TRP.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the terminal device uses the random access procedure to obtain uplink synchronization information for each TRP, then the uplink synchronization can be established, but the uplink resource overheads increase and transmission delay becomes lengthy
Solution Approach 1:
The terminal device performs downlink signal strength measurement and calculates uplink synchronization information in advance before actual uplink transmission. By pre-calculating the timing advance value based on downlink time difference of arrival, the device avoids performing random access procedure at the moment of uplink transmission, thereby reducing transmission delay while ensuring synchronization reliability
Solution Approach 2:
The patent introduces downlink signal measurement and time difference calculation as an intermediary process between downlink reception and uplink transmission. Instead of directly using random access procedure, the terminal uses downlink signal characteristics to derive uplink synchronization information, serving as a mediator that eliminates the need for lengthy random access exchange
2Reliability
If the terminal device uses the random access procedure to obtain uplink synchronization information for each TRP, then the uplink synchronization can be established, but the uplink resource overheads increase
Solution Approach 1:
The terminal device autonomously calculates uplink synchronization information by measuring downlink signals and computing time difference of arrival. This self-service approach allows the device to generate its own timing advance value without requiring network side random access responses, thereby eliminating uplink resource overheads associated with random access procedure while ensuring reliable synchronization establishment
3Loss of time
If the terminal device determines uplink synchronization information based on downlink time difference of arrival and transmission timing difference, then the transmission delay is reduced, but the complexity of synchronization management increases
Solution Approach 1:
The patent transforms the synchronization management approach by changing from event-driven random access triggers to parameter-based continuous calculation. The terminal device monitors downlink time difference of arrival and transmission timing difference parameters, dynamically adjusting uplink synchronization information based on these parameter changes, thereby reducing delay while managing complexity through parameter monitoring rather than procedural complexity
Data Source
AI summary
A wireless communication method, a terminal device, and a network device are provided. The method includes: when a terminal device is being in uplink synchronization with a first TRP, determining, by the terminal device, uplink synchronization information for a second TRP, where the uplink synchronization information for the second TRP is determined based on one or more of following information: uplink synchronization information for the first TRP; a downlink time difference of arrival, where the downlink time difference of arrival is used for indicating a difference between a time at which a signal of the first TRP arrives at the terminal device and a time at which a signal of the second TRP arrives at the terminal device; or a transmission timing difference between the first TRP and the second TRP.