Soft Buffer Allocation for Carrier Aggregation
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
In LTE communication systems, the limited soft buffer size in terminals restricts the storage of codewords during higher rate transmissions, leading to inefficiencies in HARQ incremental redundancy retransmissions, especially in dual-codeword MIMO operations, and poses challenges during carrier reconfiguration periods where synchronization between network nodes and terminals is critical.
Innovation Solution
A method where the terminal allocates its soft buffer by equally dividing it into sub-buffers across HARQ processes and further dividing each sub-buffer into codewords across all configured component carriers, ensuring full utilization of the soft buffer memory and maintaining synchronization during reconfiguration periods by adjusting transmission strategies based on received reconfiguration messages.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If the soft buffer size is increased to store complete codewords for higher rate transmissions, then the storage capacity is improved, but the terminal complexity and cost increase
Solution Approach 1:
The soft buffer is divided into multiple sub-buffers, each associated with a specific codeword. This segmentation allows the terminal to manage limited buffer resources more efficiently by allocating space only for active codewords rather than requiring a single large buffer for all possible codewords, thus reducing terminal complexity while maintaining adequate storage capacity.
2Device complexity
If the terminal uses a limited sized soft buffer for higher rate transmissions, then the terminal complexity is reduced, but the terminal cannot store complete codewords leading to transmission errors
Solution Approach 1:
The soft buffer allocation is made dynamic by allowing the terminal to request and receive soft buffer size information from the network node. The terminal can then adapt its buffer allocation strategy based on actual transmission conditions, ensuring reliable storage of complete codewords when needed while maintaining low complexity through flexible management rather than fixed oversized buffers.
3Productivity
If the eNB transmits coded bits based on assumed soft buffer size, then the transmission efficiency is improved, but mismatches in soft buffer size understanding cause soft buffer corruption
Solution Approach 1:
The terminal provides feedback to the network node about its soft buffer allocation and size. This feedback mechanism ensures that the network node's transmission assumptions match the terminal's actual buffer capacity, preventing soft buffer corruption while maintaining high transmission efficiency through coordinated resource allocation.
4Ease of operation
If the soft buffer is divided equally among HARQ processes, then the allocation simplicity is improved, but the soft buffer size per codeword is reduced limiting incremental redundancy gains
Solution Approach 1:
Instead of uniform equal division, the soft buffer allocation is optimized with local quality adjustments where codewords with higher redundancy needs or lower priority receive different portions of the buffer. This allows maintaining overall allocation simplicity while ensuring sufficient buffer space for critical codewords to maximize incremental redundancy gains.
Data Source
AI summary
A terminal (e.g., mobile communication device, UE) and a method are described herein for allocating a soft buffer after interacting with a network node (e.g., base station, eNB). In addition, a network node (e.g., base station, eNB) and a method are described herein that facilitates robust operations during a reconfiguration period while a terminal allocates a soft buffer located therein.