Soft Buffer Management via Carrier Priority Partitioning
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Solution Overview
Problem
In LTE and LTE-Advanced systems, the increasing number of component carriers in carrier aggregation leads to a significant requirement for soft-buffer capacity, which is not efficiently managed, especially when dealing with licensed and unlicensed spectrum carriers with different characteristics, resulting in inefficient HARQ operation and potential memory constraints.
Innovation Solution
The proposed solution involves prioritizing soft buffer storage based on a carrier index, allocating guaranteed memory to higher-priority carriers and providing opportunistic access to lower-priority carriers, allowing flexible control of HARQ operations across carriers with varying characteristics, and optimizing memory usage by splitting the soft buffer across a subset of configured carriers.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If carrier aggregation with multiple component carriers is implemented to increase peak data rate, then data transmission capacity is improved, but soft-buffer memory requirements increase significantly
Solution Approach 1:
The soft buffer is segmented into multiple partitions, with each partition associated with a specific component carrier. This segmentation allows the system to manage memory resources more efficiently by allocating buffer space according to carrier priority rather than requiring uniform buffer capacity across all carriers, thus reducing total memory requirements while maintaining high data rate capability
Solution Approach 2:
Different quality levels of buffer storage are assigned to different component carriers based on their priority. High-priority carriers (such as licensed spectrum carriers) receive guaranteed buffer storage with higher quality assurances, while lower-priority carriers (such as unlicensed spectrum carriers) receive opportunistic buffer access. This local differentiation optimizes memory usage by ensuring critical carriers have sufficient buffer space while reducing allocation to less critical carriers
2Ease of operation
If equal soft buffer allocation is provided to all configured component carriers, then fairness is maintained, but memory efficiency decreases and costs increase
Solution Approach 1:
Instead of uniform buffer allocation, the system implements local quality differentiation where each component carrier receives buffer allocation proportional to its priority and characteristics. Licensed spectrum carriers receive guaranteed buffer partitions while unlicensed spectrum carriers receive opportunistic access, optimizing memory usage by matching buffer quality to carrier importance rather than applying equal allocation universally
Solution Approach 2:
The system changes the buffer allocation parameter from equal distribution to priority-based distribution. By introducing carrier priority as a variable parameter, the system dynamically adjusts buffer allocation ratios based on carrier characteristics (licensed vs. unlicensed spectrum), thereby reducing total memory requirements while maintaining operational fairness for high-priority carriers
3Reliability
If soft buffer capacity is increased to support many component carriers, then HARQ performance is improved, but device complexity and cost increase
Solution Approach 1:
The soft buffer is divided into multiple partitions corresponding to different component carriers, with each partition managed independently according to carrier priority. This segmentation simplifies memory management by allowing the system to handle high-priority carriers with guaranteed buffer space separately from low-priority carriers with opportunistic access, reducing overall system complexity while maintaining HARQ performance for critical carriers
Solution Approach 2:
Different buffer management policies are applied locally to different carrier groups. High-priority carriers receive guaranteed buffer access with simplified management, while low-priority carriers use opportunistic access with more complex but less frequently activated management logic. This local quality approach reduces overall device complexity by minimizing the complexity required for critical HARQ operations
Data Source
AI summary
Soft buffer management circuitry is provided for use in a device of a wireless communication system. The soft buffer management circuitry has input circuitry for receiving information relating to an aggregated carrier comprising a plurality, NDU/ULcells, of configured component carriers. Control circuitry is provided for prioritizing allocation of storage in the soft buffer depending on a carrier index value indicating a prioritization of a corresponding component carrier relative to the other configured component carriers. The buffer is partitioned into a number min (NC, NDL/ULcells) partitions, where NC gives a number of carriers for which soft buffer storage is to be prioritized. A UE comprising the soft buffer management circuitry and a soft buffer management method are also provided.