Satellite Frame Pre-Compensation for 5G Time Alignment
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Solution Overview
Problem
Existing mobile terminals and network equipment are not interoperable between different satellite systems or with terrestrial mobile networks, limiting their use to niche markets and preventing their adoption in the consumer market, despite ongoing efforts by 3GPP to standardize 5G for satellite systems.
Innovation Solution
A method and device for pre-compensating time and frequency differences in uplink and downlink service frames exchanged between a satellite and a mobile terminal, using parameters like satellite position, velocity, and acceleration to align frames and compensate for variable delays, allowing standard equipment reuse.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If standard 5G equipment is used for satellite communication, then interoperability with terrestrial networks is maintained, but time alignment between uplink and downlink frames deteriorates due to variable propagation delays
Solution Approach 1:
The patent applies preliminary action by calculating and applying pre-compensation values for time differences before the actual transmission occurs. The base station computes expected time offsets based on satellite ephemeris data and applies these corrections in advance to downlink frames, and provides corresponding pre-compensation information to mobile terminals for uplink transmission, thereby preventing time misalignment issues before they occur.
Solution Approach 2:
The patent changes the time parameters of transmitted frames by applying pre-compensation offsets. The base station modifies the timing of downlink frames based on calculated satellite position and velocity parameters, and instructs mobile terminals to adjust their uplink transmission timing accordingly, thereby maintaining synchronization despite varying propagation delays.
2Manufacturing precision
If specialized satellite communication equipment is used, then time alignment precision is improved, but device complexity and cost increase
Solution Approach 1:
The patent makes standard 5G base stations and mobile terminals multi-functional by enabling them to perform satellite communication operations. The base station uses existing satellite ephemeris acquisition capabilities and extends its timing functions to handle pre-compensation calculations, while mobile terminals use their existing positioning and timing mechanisms augmented with pre-compensation parameters, thereby avoiding the need for specialized dedicated satellite equipment.
Solution Approach 2:
The patent enables self-service by allowing standard equipment to handle its own time alignment needs through software-based pre-compensation. The base station autonomously calculates pre-compensation values using available satellite orbital data, and mobile terminals autonomously apply received pre-compensation parameters to adjust their transmission timing, eliminating the need for complex external synchronization infrastructure.
3Adaptability or versatility
If 3GPP standard modifications are made for satellite access, then satellite interoperability is improved, but base station and core network complexity increase
Solution Approach 1:
The patent applies preliminary action by having the base station acquire satellite ephemeris data in advance and compute pre-compensation parameters before satellite communication sessions begin. This advance preparation allows the network to handle satellite-specific timing requirements through pre-calculated parameters, minimizing real-time processing complexity in the base station and core network.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
Enables seamless integration of satellite access into the 3GPP cellular ecosystem, supporting commercially available terminals and network equipment without requiring changes in their behavior, and minimizing the need for core network transformations.
Implementation Method 1
The pre-compensation is a Doppler pre-compensation for compensating frequency differences
Data Source
AI summary
A method is provided for compensating time differences for the time alignment of uplink service frames and downlink service frames, the uplink service frames and the downlink service frames being exchanged between a satellite and a mobile terminal. The mobile terminal belonging to a 5G cell comprising a cell centre, the pre-compensation is calculated on the basis of a main beam directed towards the centre (O) of the cell (5G).