Satellite Initial Access via Propagation Delay Signaling
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Solution Overview
Problem
Non-terrestrial wireless networks (NTNs) face challenges in initial access due to large propagation delays and significant Doppler shifts, especially when terminals lack GPS, complicating the initial access procedure and increasing complexity and time.
Innovation Solution
The described techniques involve communicating satellite information, such as propagation delay and Doppler data, to simplify initial access by signaling relevant information to terminals, allowing them to adjust for these factors, thereby reducing the complexity and time of the initial access procedure.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If terminals in NTNs compensate for propagation delay and Doppler shift without GPS, then initial access procedure complexity increases, but device cost and complexity are reduced
Solution Approach 1:
The patent introduces an intermediary mechanism where the network side (base station or satellite) provides reference signals and timing information that terminals can use to compensate for propagation delay and Doppler shift without requiring GPS. The network acts as a mediator that supplies the necessary synchronization data to terminals, enabling them to overcome the harmful effects of large RTD and Doppler in NTNs without increasing terminal complexity.
Solution Approach 2:
The patent applies preliminary action by having the network side pre-transmit timing reference information and synchronization signals before the terminal needs to perform initial access. This allows terminals to acquire timing synchronization and compensate for propagation delay in advance, simplifying the initial access procedure rather than calculating these parameters in real-time during access.
2Measurement precision
If GPS is used for RTD and Doppler compensation, then compensation accuracy is improved, but device cost and complexity increase
Solution Approach 1:
The network side serves as an intermediary that provides reference timing information and synchronization signals, allowing terminals to achieve accurate RTD and Doppler compensation without GPS. The network supplies the necessary reference data that would otherwise require GPS to obtain, thereby maintaining compensation accuracy while reducing terminal complexity and cost.
Solution Approach 2:
The patent uses copying by having the network transmit timing reference information and synchronization signals that terminals can copy and use for synchronization. Instead of terminals independently calculating timing parameters using GPS, they copy the reference timing information provided by the network, achieving the same synchronization effect with reduced complexity.
3Productivity
If detailed satellite information is signaled to terminals, then initial access efficiency is improved, but signaling overhead increases
Solution Approach 1:
The patent extracts only the essential satellite information needed for initial access, such as timing reference information and synchronization parameters, rather than signaling all possible satellite data. This selective extraction provides sufficient information for terminals to perform initial access efficiently while minimizing signaling overhead by omitting unnecessary details.
Solution Approach 2:
The patent applies partial action by providing a subset of satellite information that is sufficient for initial access purposes. Rather than signaling complete and excessive satellite data, the network provides the partial set of parameters (timing references, synchronization signals) that terminals need, achieving efficient access without the overhead of complete information signaling.
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
This approach simplifies the initial access procedure by providing terminals with necessary information to compensate for propagation delays and Doppler shifts, leading to more efficient initial access in NTNs.
Implementation Method 1
identifying propagation delay information associated with wireless communications between a gateway and a UE in an NTN, where the propagation delay information is identified based on a distance between a satellite in communication with the gateway and the UE and a geographical area associated with a transmission beam from the satellite
Implementation Method 2
the Doppler shift experienced by transmissions in NTNs (e.g., communications with non-geostationary satellites) may be orders of magnitude greater than the Doppler shift commonly experienced by transmissions in terrestrial networks
Data Source
AI summary
Methods, systems, devices, and apparatuses for wireless communications are described that support techniques for initial access in wireless systems. Generally, the described techniques provide for communicating satellite information to simplify initial access procedures. A wireless communications system may signal relevant information (e.g., Doppler information or propagation delay information) associated with communications through a satellite to mobile terminals (e.g., user equipment (UEs)). The mobile terminals may utilize the relevant information to generate an uplink transmission (e.g., a random access message or an initial access message) that compensates for the Doppler shift and propagation delay that may be experienced by communications between the mobile terminals and the satellite.