Non-Terrestrial Network Receivers With Dynamic Droop Compensation
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Solution Overview
Problem
Wireless communications systems face challenges in addressing the time-varying Doppler shift caused by low Earth orbit satellites, which can degrade signal quality and throughput due to uncompensated droop in front-end processing.
Innovation Solution
Implementing a Doppler-dependent droop compensation filter and a Doppler-independent droop compensation filter to address the Doppler shift, with separate filters for terrestrial and non-terrestrial networks, and utilizing a rotator for dynamic Doppler estimation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a fixed bandwidth filter is used for droop compensation, then the filter design is simple, but it cannot adequately address time-varying Doppler shifts in NTN communications
Solution Approach 1:
The patent implements a dynamic filter bandwidth adjustment mechanism that adapts the filter bandwidth based on the estimated Doppler shift. When Doppler shift is detected, the filter bandwidth is increased to accommodate the frequency variation, thereby maintaining signal quality while managing complexity through automated adaptation rather than fixed design
Solution Approach 2:
The patent changes the filter parameter (bandwidth) dynamically based on the Doppler shift conditions. The filter transitions from a fixed bandwidth configuration to a variable bandwidth configuration that responds to the time-varying Doppler effects in NTN communications, improving reliability without requiring complete redesign of the filter structure
2Reliability
If Doppler-dependent droop compensation is implemented, then signal quality improves, but computational complexity increases
Solution Approach 1:
The patent performs preliminary Doppler estimation and compensation setup before full signal processing. By estimating the Doppler shift in advance and pre-configuring the filter parameters accordingly, the system reduces the computational burden during main signal processing while still achieving Doppler-dependent droop compensation
Solution Approach 2:
The patent segments the droop compensation process into distinct stages: Doppler estimation, filter parameter adjustment, and signal filtering. This segmentation allows each component to be optimized independently, reducing overall computational complexity while maintaining signal quality through specialized processing at each stage
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 throughput by compensating for Doppler-induced droop, providing improved performance in non-terrestrial networks and reducing computational complexity.
Implementation Method 1
a signal received by a UE may exhibit a time-varying carrier frequency shift or Doppler shift up to 24 parts per million (ppm). For example, satellite motion relative to a stationary UE receiver may cause a Doppler shift in NTNs
Implementation Method 2
Doppler-dependent droop compensation may be performed using a Doppler-dependent droop compensation filter. In some approaches, Doppler-independent droop compensation may be performed. For example, a droop compensation filter may be designed for wider bandwidth that addresses a Doppler shift
Data Source
AI summary
Some wireless communications systems provide communications between user equipments (UEs) and non-terrestrial networks (NTNs). An NTN may include one or more NTN nodes (e.g., satellites). When communicating with low Earth orbit (LEO) satellites, a signal received by a UE may exhibit a time-varying carrier frequency shift or Doppler shift. Some examples of the techniques described herein may address the effects of NTN Doppler on front end processing. Some examples of the techniques described herein may use a Doppler-dependent droop compensation filter after Doppler compensation using a rotator. In some approaches, Doppler-independent droop compensation may be performed. For example, a droop compensation filter may be designed for wider bandwidth that addresses a Doppler shift. A filter for jammer rejection may be utilized based on the Doppler shift or based on an NTN or terrestrial network (TN) scenario.