Soft Buffer Management for HARQ in Carrier Aggregation
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Solution Overview
Problem
In wireless communication systems, the conventional HARQ process is limited by the reception buffer size of user equipment in multiple carrier systems, leading to a decrease in coding gain due to the increased number of HARQ processors and reduced buffer size for each process.
Innovation Solution
A method and apparatus for managing a soft buffer in user equipment to determine the size based on the maximum number of cells that can be scheduled simultaneously, allowing effective HARQ process management in multiple carrier systems while maintaining the HARQ process mechanism used in single carrier systems.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the number of HARQ processors is increased in multiple carrier systems, then the number of HARQ processes that can be performed simultaneously is increased, but the reception buffer size for each HARQ process is decreased, resulting in decreased coding gain
Solution Approach 1:
The invention segments the HARQ processes into two categories: those requiring full buffer resources (first HARQ processes) and those that can share reduced buffer resources (second HARQ processes). This segmentation allows the system to maintain coding gain for critical processes while supporting a larger total number of HARQ processes through resource sharing.
Solution Approach 2:
Different buffer allocation strategies are applied to different HARQ processes based on their specific requirements. First HARQ processes receive full buffer allocation to maintain high coding gain, while second HARQ processes receive reduced buffer allocation, creating local quality differentiation in buffer management.
2Ease of manufacture
If the reception buffer size is limited in user equipment, then manufacturing costs are reduced, but the buffer size for each HARQ process is decreased when the number of HARQ processes is increased
Solution Approach 1:
The invention applies partial buffer allocation to second HARQ processes, where not all HARQ processes receive full buffer resources. This partial action approach allows the system to operate with limited total buffer size while still providing adequate resources to critical first HARQ processes, thereby maintaining acceptable coding gain despite overall buffer constraints.
3Productivity
If carrier aggregation is implemented to increase data rate, then multiple carriers are used, but the number of HARQ processors and processes must be significantly increased
Solution Approach 1:
The invention merges the management of multiple HARQ processes across multiple carriers into a unified buffer management framework. By categorizing HARQ processes into first and second types and applying consistent buffer allocation rules across all carriers, the system reduces the complexity of managing individual HARQ processors for each carrier while still supporting increased data rates through carrier aggregation.
Data Source
AI summary
The present invention relates to a method for managing a soft buffer for the hybrid automatic repeat request (HARQ) of a terminal to which a plurality of cells are set in a wireless communication system, and to an apparatus using the method. Through the method, information is received about the maximum number of cells capable of being simultaneously scheduled from among a plurality of cells, and the size of the soft buffer is determined for storing transmission blocks or code blocks of each cell on the basis of the information.