Active Coordination Sets for NTN Delay and Doppler Compensation
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Solution Overview
Problem
Non-terrestrial communication systems face challenges such as poor signal quality, increased bit errors, and unreliable connections due to orbital velocity, interference, and limited power density, which affect user equipment (UE) mobility and hardware constraints.
Innovation Solution
Implementing active coordination sets (ACS) that involve a coordinating base station to select and compensate for propagation delay and Doppler shift, integrating terrestrial and non-terrestrial networks through joint-communication with UE, using ephemeris information and system information to form an active coordination set.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If non-terrestrial communication systems use satellite relays to provide coverage to remote locations, then coverage flexibility is improved, but signal quality deteriorates due to orbital velocity
Solution Approach 1:
The patent introduces an Active Coordination Set (ACS) as an intermediary mechanism that coordinates between terrestrial and non-terrestrial networks. The ACS includes a coordinating base station and candidate base stations that work together to manage the communication link, providing a mediator structure that handles the complexity of satellite mobility and signal quality degradation through coordinated transmission and reception operations.
Solution Approach 2:
The patent applies parameter changes by dynamically adjusting transmission parameters based on orbital velocity and propagation delay conditions. The system modifies transmission timing, frequency compensation, and synchronization parameters in response to changing satellite positions and velocities, allowing the system to adapt to the dynamic environment while maintaining signal quality.
2Adaptability or versatility
If non-terrestrial networks operate at high orbital velocities, then communication coverage is extended to remote areas, but bit errors increase
Solution Approach 1:
The patent implements preliminary action by pre-compensating for propagation delay and Doppler shift effects before transmission occurs. The system calculates and applies compensation factors based on predicted satellite positions and orbital parameters, preparing the transmission parameters in advance to counteract the harmful effects of high orbital velocity and reduce bit errors.
Solution Approach 2:
The system employs feedback mechanisms where the coordinating base station receives information about actual transmission conditions and adjusts parameters accordingly. The feedback loop includes monitoring bit error rates and signal quality, then using this information to refine transmission parameters and improve overall reliability in the high-velocity satellite environment.
3Reliability
If active coordination sets combine terrestrial and non-terrestrial networks, then service reliability is improved, but system complexity increases
Solution Approach 1:
The patent segments the coordination function into distinct components: a coordinating base station that manages control plane operations, candidate base stations that provide transmission alternatives, and UE-specific coordination logic. This segmentation divides the complex system into manageable functional blocks that can operate semi-independently, reducing overall system complexity while maintaining reliability.
Solution Approach 2:
The Active Coordination Set framework provides multi-functionality by handling multiple operations through a unified structure: it manages both terrestrial and non-terrestrial network connections, performs timing and frequency compensation, coordinates transmission and reception, and adapts to different satellite configurations. This universal approach consolidates multiple functions into a single coordinated system, reducing complexity compared to separate specialized systems.
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
Enhances signal quality and reliability by compensating for delay and Doppler effects, improving UE connectivity and reducing bit errors in non-terrestrial networks.
Implementation Method 1
sends the UE's rough location information to the NTN BS that directs the NTN BS to precompensate for propagation delay and/or Doppler shift during downlink joint-transmissions in the ACS and compensate for propagation delay and/or Doppler shift during uplink joint-receptions in the ACS
Implementation Method 2
sends the UE's rough location information to the NTN BS that directs the NTN BS to precompensate for propagation delay and/or Doppler shift during downlink joint-transmissions in the ACS and compensate for propagation delay and/or Doppler shift during uplink joint-receptions in the ACS
Data Source
AI summary
In aspects, a coordinating base station that forms an active coordination set (ACS) is described that includes at least the coordinating base station and a non-terrestrial network base station (NTN BS) for joint-communication with a user equipment (UE). Based on an evaluation of terrestrial channel conditions for the UE, the coordinating base station selects one or more non-terrestrial NTN BSs as candidate base stations to add to the ACS. The coordinating base station transmits ephemeris information for the one or more NTN BSs to the UE. The UE acquires and measures signal quality of each of the NTN BSs and sends an indication to the coordinating base station. Based on the indication, the coordinating base station sends an invitation to the NTN BS to join the ACS which communicates using timing and frequency compensation to compensate for distance and Doppler effects.