Soft Buffer Size Determination for 8-Layer MIMO and 256 QAM
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Solution Overview
Problem
Current 3GPP specifications lack a method to determine the soft buffer size for new UE categories supporting bit rates higher than 1 Gbps but less than 3 Gbps, leading to inadequate HARQ process performance and improper rate matching by base stations.
Innovation Solution
A method is developed to calculate the soft buffer size for UE categories supporting up to 8-layer MIMO and 256 QAM, allowing proper communication by defining new UE categories with specific soft buffer sizes and modulation schemes, enabling accurate rate matching and HARQ processes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If 8-layer MIMO and 256 QAM are configured for new UE categories to achieve higher bit rates, then the data transmission rate is improved, but the soft buffer size becomes insufficient for proper HARQ processing
Solution Approach 1:
The patent changes the parameter of soft buffer size allocation by introducing a new determination method that considers the number of MIMO layers and modulation scheme. Specifically, when 8-layer MIMO and 256 QAM are configured, the soft buffer size is determined using a new formula that allocates sufficient buffer space proportional to the increased data rate requirements, thereby maintaining HARQ process reliability while supporting higher transmission rates.
2Reliability
If the soft buffer size is increased to support 8-layer MIMO and 256 QAM, then the HARQ process reliability is improved, but the device complexity increases
Solution Approach 1:
The patent implements a dynamic soft buffer size determination mechanism where the buffer size is not fixed but adapts based on the configured MIMO layers and modulation scheme. The base station and user equipment dynamically calculate the required soft buffer size using a determination formula that incorporates the actual transmission parameters, allowing the system to allocate exactly the necessary buffer resources rather than provisioning for maximum possible complexity in all cases.
3Adaptability or versatility
If a new UE category is defined without a specific soft buffer size determination method, then the adaptability to different configurations is improved, but the communication reliability deteriorates due to improper rate matching
Solution Approach 1:
The patent introduces a specific parameter determination method for soft buffer size that changes based on the UE category and transmission configuration. The determination formula incorporates parameters such as the number of MIMO layers and modulation scheme order, creating a systematic way to calculate appropriate buffer sizes for different UE categories including new categories supporting 8-layer MIMO and 256 QAM, thereby maintaining both adaptability and reliability.
Data Source
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AI summary
There is provided a user apparatus of a radio communication system provided with a base station and the user apparatus, the user apparatus including a determination unit configured to determine a size of a soft buffer to be secured within the user apparatus based on a total soft buffer size corresponding to a UE category of the user apparatus, a modulation scheme configured for a downlink by the base station, and a MIMO-layer number configured for the downlink by the base station; and a receiving unit configured to store data received from the base station in the soft buffer with the size determined by the determination unit, wherein the UE category includes 2 layers, 4 layers, and 8 layers as maximum MIMO-layer numbers to be supported, and the UE category includes 64 QAM and 256 QAM as the modulation schemes to be supported.