Soft Buffer Partitioning for Cross-TTI HARQ Switching
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Current LTE and NR systems face challenges in efficiently managing soft buffers for dynamic switching between different Transmission Time Intervals (TTIs) and subcarrier spacings, leading to limitations in throughput and latency performance due to the need for complex and costly soft buffer management mechanisms.
Innovation Solution
The implementation of a soft buffer management mechanism that allows for full or partial sharing of soft buffer resources across different TTI lengths, including HARQ process pairing and dynamic partitioning based on signaled weighting factors, to enable efficient cross-TTI-Type HARQ operations and flexible retransmissions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of time
If dynamic switching between different TTI lengths is implemented, then latency performance is improved, but soft buffer management complexity increases
Solution Approach 1:
The soft buffer is segmented into multiple partitions, with each partition associated with a specific HARQ process. When switching between TTI lengths, the system selectively accesses specific buffer partitions corresponding to the active HARQ processes, avoiding the need to manage the entire buffer dynamically. This segmentation allows efficient TTI switching while maintaining organized buffer management.
Solution Approach 2:
The system performs preliminary configuration of HARQ processes and their associated soft buffer partitions before TTI switching occurs. By pre-establishing the mapping between HARQ processes and buffer partitions for different TTI lengths, the system avoids complex real-time buffer management decisions during switching, reducing operational complexity while enabling low-latency switches.
2Reliability
If separate soft buffers are allocated for different TTI types, then reliability of HARQ operations is improved, but resource utilization efficiency deteriorates
Solution Approach 1:
The soft buffer is designed with a unified structure that serves multiple TTI types through HARQ process pairing. Each soft buffer partition is associated with HARQ processes that can operate across different TTI lengths. This universal buffer design maintains reliability by providing dedicated storage for each HARQ process while improving resource utilization by allowing the same buffer infrastructure to support both long and short TTI operations.
Solution Approach 2:
The system changes the operational parameters of HARQ processes based on TTI type while maintaining the same soft buffer structure. By adjusting parameters such as process timing and buffer access patterns rather than creating separate buffers, the system achieves reliable HARQ operations for different TTI types while improving overall resource utilization efficiency.
3Adaptability or versatility
If complex soft buffer management mechanisms are implemented, then support for multiple TTI lengths is improved, but implementation cost increases
Solution Approach 1:
The system segments the soft buffer into standardized partitions that can be systematically allocated to different TTI types. This segmentation approach enables support for multiple TTI lengths using a regular, predictable buffer structure rather than requiring complex dynamic allocation mechanisms, thereby reducing implementation cost while maintaining versatility.
Solution Approach 2:
The system performs preliminary configuration and mapping of HARQ processes to soft buffer partitions for different TTI lengths before operation begins. This pre-configuration establishes clear rules for buffer access and management, enabling multi-TTI length support through simple, predetermined operations rather than complex real-time decisions, thus reducing implementation complexity and cost.
Data Source
AI summary
A device of a User Equipment (UE) includes a soft buffer including a plurality of soft buffer partitions to store a plurality of soft bits for a number of hybrid automatic retransmission request (HARQ) processes, wherein the number of HARQ processes includes first HARQ processes corresponding to a first Time Transmission Interval (TTI) Type of a first duration (TTI Type 1), and second HARQ processes corresponding to a second TTI Type of a second duration (TTI Type 2) shorter than the first duration. The device further includes processing circuitry to communicate with a base station in a cellular network, the processing circuitry further to effect a dynamic switching between a TTI Type 1 communication mode and a TTI Type 2 communication mode, and to selectively access the soft buffer partitions to perform, based on the switching, at least one of the first HARQ processes and the second HARQ processes.