Wireless Communication With Satellite-Delay Feedback for NTN Mobility
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Solution Overview
Problem
In Non-Terrestrial Network (NTN) scenarios, the unknown difference in propagation delays between satellites and terminals hinders accurate neighbor cell measurement configuration, leading to failures in mobility control due to insufficient SMTC and measurement gap configurations.
Innovation Solution
The terminal device reports signal propagation distance, delay, or quality information to the network device, allowing it to adjust SMTC and measurement gaps based on these differences, optimizing neighbor cell measurement configurations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If traditional terrestrial communication measurement configuration is used in NTN scenarios, then device complexity is reduced, but measurement precision deteriorates due to unknown propagation delay differences between satellites and terminals
Solution Approach 1:
The terminal device measures propagation delay to the serving satellite and feeds back this information to the network device. The network device uses this feedback to calculate the propagation delay difference between serving and neighbor satellites, then configures appropriate SMTC and measurement gap parameters. This feedback mechanism enables accurate measurement configuration while maintaining relatively simple device implementation.
Solution Approach 2:
The network device performs preliminary calculation of propagation delay differences using satellite ephemeris data and terminal location information before configuring measurement parameters. By pre-calculating the delay compensation values and incorporating them into the measurement configuration, the system achieves precise measurement setup without requiring complex real-time calculations at the terminal device.
2Reliability
If propagation delay difference is not considered in SMTC and measurement gap configuration, then device complexity is reduced, but reliability deteriorates due to failed mobility control
Solution Approach 1:
The terminal provides feedback on its measured propagation delay to the serving satellite, enabling the network device to accurately determine the propagation delay difference. This feedback allows the network device to configure reliable SMTC and measurement gap parameters that account for satellite-specific delays, ensuring successful mobility control while keeping terminal device complexity low.
Solution Approach 2:
The system dynamically adjusts SMTC window timing and measurement gap duration based on the calculated propagation delay difference between serving and neighbor satellites. By changing these configuration parameters according to the specific satellite geometry and terminal location, the system achieves reliable mobility control adapted to NTN conditions without requiring fundamental changes to device architecture.
3Measurement precision
If satellite-specific propagation delays are accounted for in measurement configuration, then measurement precision is improved, but loss of time increases due to additional information exchange and calculation
Solution Approach 1:
The network device performs preliminary calculation of propagation delay differences using pre-acquired satellite ephemeris data and terminal location information before the measurement process begins. By pre-computing the delay compensation values and embedding them in the measurement configuration messages, the system minimizes additional information exchange time while achieving precise satellite-specific measurement configuration.
Solution Approach 2:
The terminal device independently measures its propagation delay to the serving satellite using standard uplink timing procedures already present in the system. This self-measured delay information is then used by the network device to calculate the propagation delay difference, eliminating the need for separate dedicated measurement message exchanges and reducing overall signaling overhead and time loss.
Data Source
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AI summary
The embodiments of the present disclosure provide a wireless communication method, a terminal device, and a network device. The network device can learn a difference between propagation delays from a serving satellite and a neighbor satellite to a terminal, thereby optimizing neighbor cell measurement configuration. The wireless communication method includes: transmitting, by a terminal device, first information including at least one of: signal propagation distance information from a serving satellite and a neighbor satellite of the serving satellite to the terminal device; signal propagation delay information from the serving satellite and the neighbor satellite of the serving satellite to the terminal device; or signal quality of the serving satellite and/or at least one neighbor satellite of the serving satellite as measured by the terminal device.