NTN Satellite Diversity Transmission for Delay and Doppler Mismatch
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Solution Overview
Problem
The challenge in non-terrestrial networks (NTN) is the difficulty in applying multi-TRP transmission techniques due to significant differences in transmission delays and Doppler shifts between satellite links, particularly for terminals with low antenna gain or low link budgets, which degrade link quality.
Innovation Solution
A method and apparatus for diversity transmission in NTN that involves allocating reference signals to multiple satellites, compensating for time delays and Doppler shifts, and determining a transmission mode based on RS measurement reports to enhance data transmission efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If multi-TRP transmission techniques are applied in NTN, then link quality can be improved through diversity transmission, but transmission becomes infeasible due to significant differences in transmission delays and Doppler shifts between satellite links
Solution Approach 1:
The patent changes the parameters of reference signals by applying different time delays and Doppler shifts to reference signals transmitted via different satellites. This allows the receiver to compensate for the significant differences in transmission characteristics between satellite links, making diversity transmission feasible in NTN environments where traditional multi-TRP techniques would fail
Solution Approach 2:
The patent performs preliminary compensation of time delays and Doppler shifts on reference signals before transmission through multiple satellite links. By pre-adjusting these parameters, the system ensures that reference signals from different satellites can be properly measured and compared at the receiver, enabling diversity transmission to improve link quality without being overwhelmed by parameter mismatches
2Reliability
If diversity transmission utilizing multiple satellites is implemented, then performance can be enhanced for terminals with low antenna gain or low link budget, but it is difficult to directly apply terrestrial multi-TRP techniques due to significant differences in transmission delay and Doppler shift
Solution Approach 1:
The patent modifies the reference signal parameters by applying satellite-specific time delays and Doppler shifts, creating an adapted transmission scheme that works for NTN environments. This parameter adjustment makes diversity transmission applicable to satellite networks while maintaining the performance benefits needed for terminals with low antenna gain or link budget
Solution Approach 2:
The patent segments the reference signal transmission by allocating separate reference signals to different satellites with individually adjusted time delays and Doppler shifts. This segmentation allows each satellite link to be optimized independently, making the overall diversity transmission system adaptable to NTN conditions while preserving performance enhancements
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
The method allows for efficient data transmission by compensating for differences in transmission delay and Doppler shift, enabling either single or diversity transmission modes to improve link quality in NTN environments.
Implementation Method 1
differences in transmission delays and Doppler shifts between links via different satellites
Implementation Method 2
differences in transmission delays and Doppler shifts between links via different satellites
Data Source
AI summary
The present disclosure relates to a method of a base station in an NTN, and may comprise the steps of: allocating an RS corresponding to each of a first satellite and a second satellite; controlling that data and the RS corresponding to each satellite are transmitted to a UE through the first satellite and the second satellite; receiving an RS measurement report message from the UE; and determining, on the basis of the received RS measurement report message, a transmission mode from among a single transmission mode in which the data is transmitted through one of the first satellite and the second satellite, and a diversity transmission mode in which the data is transmitted through both the first satellite and the second satellite.