Non-Terrestrial Cellular Links with Doppler and Delay Compensation
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Solution Overview
Problem
Existing cellular communication standards are inadequate for providing reliable wireless data communication in remote areas without fixed infrastructure, especially for IoT devices with limited power, as they assume unlimited power and stationary locations, lacking solutions for non-terrestrial networks.
Innovation Solution
A method for a terminal device in a non-terrestrial cellular network that includes providing flight trajectory data and terminal location data to determine available communication slots, scheduling data transmission, and compensating for Doppler shift and delay using a data processing unit, enabling communication with airborne or spaceborne base stations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If traditional fixed cellular network infrastructure is deployed in remote areas, then network coverage is provided, but construction cost and complexity increase significantly due to low population density
Solution Approach 1:
The patent applies the dynamics principle by transitioning from static ground-based base stations to mobile non-terrestrial base stations (satellites, balloons, drones) that can move to provide network coverage. This dynamic infrastructure can be repositioned to serve remote areas temporarily without requiring permanent construction, thereby reducing infrastructure complexity while maintaining coverage reliability.
Solution Approach 2:
The patent moves the network infrastructure from the terrestrial plane to the non-terrestrial dimension (space, atmosphere). By deploying base stations on satellites, balloons, or drones operating in three-dimensional space above the Earth's surface, the system provides coverage to remote areas without requiring ground-based infrastructure construction.
2Reliability
If cellular network infrastructure is constructed in remote areas with low population density, then network access is provided, but construction and maintenance costs become excessively high
Solution Approach 1:
Instead of building permanent fixed infrastructure in low-density remote areas, the patent employs dynamic non-terrestrial base stations that can be repositioned or reused across multiple locations. This eliminates the need for costly construction and maintenance of permanent ground infrastructure while ensuring network access availability through mobile platforms.
Solution Approach 2:
The non-terrestrial base stations serve multiple functions and multiple geographic areas. A single satellite or drone can provide network access to numerous remote locations sequentially, making the infrastructure universally applicable across different regions rather than requiring dedicated infrastructure for each specific remote area.
3Reliability
If existing communication standards are used for non-terrestrial networks, then infrastructure can be deployed, but power consumption exceeds available limits for battery-powered IoT devices
Solution Approach 1:
The patent modifies communication parameters specifically for non-terrestrial scenarios, including adjusting transmission power levels, modulation schemes, and timing synchronization to account for satellite motion and varying signal conditions. These parameter changes enable reliable communication while optimizing power consumption for battery-powered IoT devices operating in remote areas.
Solution Approach 2:
The system performs preliminary actions by predicting satellite positions and communication opportunities in advance. Terminal devices can schedule their transmissions to coincide with optimal satellite passes, avoiding unnecessary power consumption during periods when no satellite is visible or when communication conditions are poor.
4Area of stationary object
If non-terrestrial base stations are deployed, then coverage in remote areas is achieved, but Doppler shift and transmission delays increase due to motion and distance
Solution Approach 1:
The patent implements feedback mechanisms where the non-terrestrial base station continuously monitors and measures the Doppler shift and transmission delay affecting signals from terminal devices. Based on this feedback, the base station adjusts its reception parameters and timing to compensate for the motion-induced effects, thereby maintaining signal accuracy despite the expanding coverage area and relative motion.
Solution Approach 2:
The system applies preliminary anti-action by pre-compensating for expected Doppler shift and timing delays based on predicted satellite positions and velocities. Before actual signal transmission or reception occurs, the system adjusts frequencies and timing offsets to counteract the anticipated effects of satellite motion, thereby maintaining measurement precision across the expanded non-terrestrial coverage area.
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 efficient power management and communication with non-terrestrial base stations, allowing IoT devices to connect to global networks without fixed infrastructure by predicting availability and compensating for transmission delays and frequency shifts.
Implementation Method 1
compensating for transmission delays and frequency shifts
Data Source
AI summary
In an embodiment, a method for estimating a location of a terminal device of a non-terrestrial cellular data communication network, where the non-terrestrial cellular data communication network has one or more airborne or spaceborne base stations moving along a respective flight trajectory and the terminal device, includes the following. At the terminal device, performing a random wake-up and a blind acquisition of a carrier that is made available by a respective one of one or more airborne or spaceborne base stations to attach the terminal device to the non-terrestrial cellular data communication network; and, once the terminal device attaches successfully to the non-terrestrial cellular data communication network via one of the one or more base-stations, estimating terminal location data based on arrival times of at least three reference timing signals received at the terminal device from different positions taken by the one or more airborne or spaceborne base stations.