TDD HARQ Resource Mapping for Mixed UL/DL Configurations
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Solution Overview
Problem
In LTE/LTE-A systems with time-division duplexing (TDD), legacy and advanced UEs may experience HARQ resource collisions due to different UL/DL configurations, leading to communication disruptions.
Innovation Solution
The advanced UE determines new association sets for HARQ resources based on the legacy UE's configuration, replacing subsets to avoid collisions and configuring mappings that respect both configurations, ensuring separate resource regions for HARQ feedback.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If the legacy UE and advanced UE use the same HARQ resource for feedback transmission, then the system maintains simplicity in resource allocation, but HARQ resource collision occurs when UEs have different UL/DL configurations
Solution Approach 1:
The patent segments the HARQ resource space by creating separate resource regions for legacy UEs and advanced UEs. The network device allocates first HARQ resources to legacy UEs and second HARQ resources to advanced UEs, ensuring that the resource sets do not overlap. This segmentation eliminates collisions while maintaining manageable complexity through structured resource division.
Solution Approach 2:
The patent applies local quality by allowing different HARQ resource allocation strategies for different UE types. Legacy UEs use traditional resource allocation based on their UL/DL configuration, while advanced UEs use a separate resource allocation mechanism that considers both legacy and advanced UE configurations. This localized differentiation resolves conflicts without requiring complete system redesign.
2Reliability
If the network allocates separate HARQ resources for legacy UE and advanced UE, then HARQ resource collision is avoided, but the resource allocation complexity increases
Solution Approach 1:
The network device performs preliminary action by pre-configuring separate HARQ resource regions for legacy and advanced UEs before actual data transmission. The association between downlink subframes and uplink HARQ feedback resources is established in advance, with the network device determining first association sets for legacy UEs and second association sets for advanced UEs that are guaranteed to be non-overlapping. This preliminary setup prevents collisions without requiring complex real-time resource management.
3Adaptability or versatility
If the UL/DL configuration is changed with lower periodicity to match fast varying traffic, then system adaptability improves, but HARQ resource collision risk increases due to configuration changes
Solution Approach 1:
The patent introduces dynamics by allowing the network device to flexibly adjust UL/DL configurations for advanced UEs while maintaining stable configurations for legacy UEs. The network can change the additional UL/DL configuration with lower periodicity to adapt to fast varying traffic, while the first UL/DL configuration remains stable. The HARQ resource allocation dynamically adapts to these configuration changes through the separate resource region approach, preventing collisions even when configurations change frequently.
Data Source
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AI summary
A method of determining HARQ resource of a UL subframe comprises determining a first new association set of the UL subframe according to an association set of the UL subframe of a first UL/DL configuration of a legacy communication device; replacing a subset of the first new association set by a subset of an association set of the UL subframe of a second UL/DL configuration of an advanced communication device, when the legacy communication device is not able to perform a reception in at least one subframe corresponding to the subset of the first new association set; configuring a mapping between at least one sequence index of the UL subframe of the first UL/DL configuration and the first new association set according to the first UL/DL configuration; and determining the HARQ resource of the UL subframe according to the mapping and the first new association set.