Soft Buffer Segmentation for Mixed TTI HARQ Decoding
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Solution Overview
Problem
Conventional HARQ control in future radio communication systems, such as 5G, fails when data is transmitted using varying transmission time intervals (TTIs), leading to potential data decoding failures and reduced communication throughput.
Innovation Solution
A user terminal with a receiving section that saves soft bits of downlink signals and controls the decoding process using these saved bits and retransmitted signals, while avoiding the use of soft bits corresponding to signals transmitted in shorter TTIs when they overlap with longer TTI resources.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If varying TTI lengths are used in one carrier to meet different service requirements, then service flexibility and adaptability are improved, but data decoding reliability deteriorates due to HARQ control failure
Solution Approach 1:
The patent segments the soft buffer into multiple buffers, with each buffer corresponding to a specific TTI length. This segmentation allows the system to store and manage soft bits for different TTI lengths separately, preventing interference between them during HARQ decoding operations.
Solution Approach 2:
The patent introduces a soft buffer as an intermediary storage mechanism between the receiving section and the decoding section. This soft buffer temporarily stores soft bits before decoding, allowing the system to handle varying TTI lengths and maintain decoding reliability through proper buffer management.
2Productivity
If multiple TTI lengths are used in one carrier, then communication throughput is improved, but HARQ-based data retransmission control becomes ineffective
Solution Approach 1:
The patent divides the soft buffer into separate buffers for different TTI lengths, enabling independent management of soft bits. This segmentation allows HARQ control to function effectively even when multiple TTI lengths are used, as each buffer can be properly managed according to its corresponding TTI length.
Solution Approach 2:
The patent changes the parameter of soft buffer organization from a single unified buffer to multiple specialized buffers, each associated with a specific TTI length. This parameter change enables the system to maintain HARQ control effectiveness while supporting varying TTI lengths for improved throughput.
3Productivity
If soft bits from short TTIs are included in long TTI decoding, then resource utilization is improved, but decoding accuracy deteriorates due to resource overlap conflicts
Solution Approach 1:
The patent segments the soft buffer into separate buffers for different TTI lengths, preventing mixing of soft bits from different TTI lengths. This ensures that only appropriate soft bits are used in decoding operations, maintaining decoding accuracy while still allowing efficient resource utilization through proper buffer management.
Solution Approach 2:
The patent applies local quality by creating specialized soft buffers tailored to specific TTI lengths. Each buffer is optimized for its corresponding TTI length, ensuring that soft bits are correctly identified and used in decoding operations, thereby maintaining high decoding accuracy.
Data Source
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AI summary
The present invention is designed so that data can be decoded suitably even when multiple transmission time interval lengths are used in one carrier. According to one aspect of the present invention, a user terminal has a receiving section that receives a DL signal in a second transmission time interval (TTI) having a longer TTI length than a first TTI, and a control section that saves soft bits of the received DL signal, and controls a decoding process using the saved soft bits and a retransmitted DL signal, and, when a DL signal that is transmitted in the first TTI is scheduled in a resource allocated to the DL signal transmitted in the second TTI, the control section controls the decoding process without using a soft bit corresponding to the DL signal that is transmitted in the first TTI.