IAB Node Timing Synchronization for 5G NTN Backhaul
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Solution Overview
Problem
There is a need for further study on deriving Integrated Access and Backhaul (IAB-DU) transmission timing when an IAB-MT is connected to a Non-Terrestrial Network (NTN) in 5G New Radio (NR) systems, as existing methods for terrestrial networks are not applicable.
Innovation Solution
A radio node and communication method that determines whether an IAB-MT is connected to an NTN and derives DU transmission timing using alternative synchronization sources like GNSS or PTP, and adjusts timing based on extended Timing Advance (TA) values and additional parameters to align DU transmission timings among IAB nodes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If traditional terrestrial network timing methods are used for IAB nodes, then timing synchronization is achieved in terrestrial networks, but timing accuracy deteriorates when MT is connected to NTN due to different propagation delay characteristics
Solution Approach 1:
The patent changes the timing derivation parameters based on network type. When MT is connected to NTN, it uses NTN-specific parameters including satellite orbital information, propagation delay calculations, and timing advance values that account for the much larger distances involved in satellite communication compared to terrestrial networks. This parameter adaptation resolves the contradiction by ensuring timing accuracy is maintained through appropriate parameter selection for each network type.
Solution Approach 2:
The patent introduces an intermediary timing adjustment mechanism that mediates between the NTN backhaul link timing and the access link timing. The IAB node calculates timing advance values and propagation delays as intermediary parameters to synchronize the DU transmission timing even when the MT is connected to NTN with different timing characteristics. This intermediary calculation layer resolves the timing synchronization issue across different network types.
2Adaptability or versatility
If a single timing derivation method is used for all IAB nodes, then device complexity is reduced, but adaptability to different network types (terrestrial and NTN) deteriorates
Solution Approach 1:
The patent implements dynamic timing derivation where the IAB node adaptively selects and adjusts timing parameters based on whether it is connected to terrestrial or NTN. The node dynamically calculates timing advance values, propagation delays, and transmission timings based on real-time network type detection and satellite orbital information. This dynamic adaptation enables versatility across network types while managing complexity through automated parameter adjustment rather than multiple static configurations.
Solution Approach 2:
The patent creates a universal timing derivation framework that can handle both terrestrial and NTN connections through a unified set of procedures. The IAB node uses a common timing derivation structure that automatically adapts to different network types by incorporating network-type-specific parameters such as satellite position, orbital velocity, and propagation delay. This universal approach provides multi-functionality without requiring entirely separate timing mechanisms for each network type.
Data Source
AI summary
A wireless node is disclosed including: a control unit for determining whether a mobile termination (MT) is connected to a non-terrestrial network (NTN), and, if the MT is connected to the NTN, deriving a transmission timing for a distributed unit (DU) by a method different from when the MT is not connected to the NTN; and a transmission unit for transmitting a signal to a child node and/or a terminal at the transmission timing for the DU.