Terminal Soft Buffer Segmentation for NTN Retransmission Control
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Solution Overview
Problem
In Non-Terrestrial Networks (NTNs) like satellite communications, the large propagation delay and increased number of processes in Hybrid Automatic Repeat Request (HARQ) lead to increased soft buffer size in terminals, which raises costs and chip size, while reducing the number of processes decreases throughput and user experience due to delayed retransmissions.
Innovation Solution
A terminal and base station configuration that includes control circuitry to manage buffering based on priority information, allowing for efficient retransmission control by prioritizing data storage and combining in the soft buffer, reducing the need for large buffers while maintaining high-priority data throughput.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the number of HARQ processes is increased to handle large propagation delay in NTN, then retransmission reliability is improved, but soft buffer size increases leading to higher terminal costs and larger chip size
Solution Approach 1:
The patent segments the soft buffer into multiple independent buffer regions, each associated with a specific HARQ process. This segmentation allows the buffer to be efficiently managed by allocating memory in discrete units corresponding to individual HARQ processes, reducing the overall buffer size requirement while maintaining support for multiple concurrent processes needed in NTN environments with large propagation delays
Solution Approach 2:
The patent implements dynamic buffer management where the buffer allocation and HARQ process activation are adapted based on current channel conditions and traffic requirements. The terminal can dynamically adjust the number of active HARQ processes and buffer usage patterns to match the propagation delay characteristics of the specific NTN scenario, optimizing the balance between reliability and buffer size
2Volume of stationary object
If the number of HARQ processes is decreased to reduce soft buffer size, then terminal costs and chip size are reduced, but throughput decreases and user experience deteriorates due to delayed retransmissions
Solution Approach 1:
The patent changes key parameters including the buffer size configuration, HARQ process timing, and combining window duration to optimize performance for NTN conditions. By adjusting these parameters based on the specific propagation delay and channel characteristics, the system achieves adequate throughput and user experience while maintaining a reduced buffer size suitable for cost-effective terminal implementation
3Productivity
If larger soft buffer is allocated to maintain throughput in NTN, then retransmission performance is preserved, but terminal hardware costs increase
Solution Approach 1:
The patent segments the buffer management approach by creating separate buffer regions for different HARQ processes and prioritizing them based on traffic type and channel conditions. This segmentation enables the system to maintain throughput performance by efficiently utilizing a smaller total buffer size through optimized allocation and reuse of buffer resources across multiple processes
Solution Approach 2:
The patent implements a buffer recovery mechanism where buffer resources are promptly released and made available for reuse after successful decoding or timeout. This discarding and recovering approach ensures that the limited buffer space is continuously utilized for active retransmission processes, maintaining throughput performance without requiring permanently allocated large buffer memory, thus reducing terminal hardware costs
Data Source
AI summary
The present invention implements appropriate retransmission control processing in accordance with a radio propagation environment. This terminal is provided with a reception circuit for receiving control information relating to buffering for retransmission control, and a control circuit for controlling buffering on the basis of the control information.