Adaptive Non-Terrestrial Packet Retransmissions Through Terrestrial RAN
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Solution Overview
Problem
Existing wireless communication systems face challenges in efficiently handling non-terrestrial network data retransmissions due to varying quality of service requirements and network energy saving modes, particularly in environments with mobile user equipment and diverse RAN resource demands.
Innovation Solution
A method is introduced where a terrestrial radio network node facilitates the reception of a delegated hybrid automatic repeat request from user equipment, transmitting a non-terrestrial payload fetch request to retrieve retransmitted protocol data units, and managing retransmissions based on channel conditions and latency criteria using modulation and coding schemes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Area of stationary object
If non-terrestrial network nodes transmit protocol data units to user equipment, then coverage area is extended, but retransmission latency increases due to orbital distance
Solution Approach 1:
A terrestrial relay node is introduced as an intermediary between the non-terrestrial network node and user equipment. The terrestrial node receives protocol data units from the non-terrestrial node, stores them temporarily, and handles retransmissions locally, thereby reducing retransmission latency while maintaining extended coverage benefits
Solution Approach 2:
The retransmission function is segmented from the non-terrestrial network node and assigned to a terrestrial relay node. This separation allows the non-terrestrial node to focus on initial transmission while the terrestrial node handles time-sensitive retransmission operations
2Productivity
If terrestrial radio network nodes handle retransmissions for non-terrestrial traffic, then retransmission efficiency improves, but network complexity increases
Solution Approach 1:
The terrestrial relay node is designed with multi-functionality, handling both terrestrial and non-terrestrial network traffic. By making the terrestrial node universal in its capabilities, the system improves retransmission efficiency without requiring dedicated complex infrastructure for each network type
Solution Approach 2:
The functions of non-terrestrial and terrestrial networks are merged at the relay node, which processes both types of traffic through unified protocols and procedures, thereby improving efficiency while managing complexity through consolidation rather than multiplication of components
3Reliability
If hybrid automatic repeat request protocols are used for non-terrestrial communications, then data reliability improves, but protocol complexity increases
Solution Approach 1:
The hybrid automatic repeat request protocol is configured with adjustable parameters such as redundancy versions and modulation and coding schemes. These parameters are dynamically changed based on channel conditions and traffic requirements, improving data reliability while managing complexity through adaptive rather than fixed configurations
Solution Approach 2:
The protocol operates dynamically, with the terrestrial relay node adapting transmission parameters, redundancy levels, and coding schemes in real-time based on feedback from user equipment and current channel conditions, thereby improving reliability while avoiding the rigidity of static complex protocols
Data Source
AI summary
A user equipment may receive downlink traffic packets according to a communication session with a non-terrestrial network node. The user equipment may request that retransmission of payload packet(s) transmitted by the non-terrestrial node to the user equipment that is/are unsuccessfully decoded by the user equipment be delegated to a terrestrial radio access network node. The user equipment may include modulation and coding scheme information and redundancy version information in a request to the terrestrial node for delegated retransmission of unsuccessfully decoded packet received from the non-terrestrial node. The terrestrial node may request and receive, from core network equipment or non-terrestrial node equipment, payload packet(s) for which the user equipment requested delegated retransmission, and may retransmit, to the user equipment, the requested payload according to the modulation and coding scheme and a next redundancy value with respect to transmission by the non-terrestrial node of the unsuccessfully decoded payload packet(s).