Uplink Control Channel Resource Allocation in TDD Wireless Systems
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Solution Overview
Problem
In wireless communication systems, particularly in TDD mode, efficiently allocating uplink resources for HARQ feedback is challenging due to the need for unique resources for each subframe while minimizing overhead, especially when there are fewer uplink subframes than downlink subframes, which affects data transmission resources.
Innovation Solution
A method in a radio network node involves dividing downlink control channel resources into subsets and associating each subset with unique uplink control channel resources, allowing for efficient allocation and reducing overhead by scheduling only a subset of downlink control channel resources in all subframes, thereby minimizing the number of reserved uplink resources.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If unique uplink resources are allocated for each downlink subframe in TDD mode, then HARQ feedback reliability is improved, but uplink control channel overhead increases
Solution Approach 1:
The patent segments the downlink control channel resources into multiple subsets, where each subset is associated with a specific uplink control channel resource. This segmentation allows the system to allocate uplink resources more efficiently by grouping downlink subframes that can share the same uplink feedback resource, thereby reducing overall uplink control channel overhead while maintaining HARQ feedback reliability.
Solution Approach 2:
The patent implements a mapping relationship where a single uplink control channel resource can serve multiple downlink control channel resource subsets. This multi-functionality allows one uplink resource to carry HARQ feedback for multiple downlink subframes, reducing the total number of uplink resources needed while ensuring reliable feedback transmission.
2Reliability
If more uplink resources are reserved for HARQ feedback, then feedback transmission reliability is improved, but resources available for data transmission decrease
Solution Approach 1:
By segmenting downlink control channel resources into subsets and mapping multiple subsets to shared uplink resources, the patent reduces the total number of uplink resources dedicated to HARQ feedback. This frees up time-frequency resources that can be reallocated for data transmission, thereby improving data transmission capacity while maintaining sufficient feedback reliability through the segmented mapping structure.
3Reliability
If downlink control channel resources are scheduled in all subframes, then downlink transmission reliability is improved, but uplink control channel resource requirements increase
Solution Approach 1:
The patent divides downlink control channel resources into multiple subsets that can be scheduled across different subframes. By associating these subsets with uplink control channel resources through a mapping relationship, the system can achieve reliable downlink transmission without requiring proportional uplink resources for every downlink subframe, thus reducing overall uplink control channel resource requirements.
Data Source
Figure 1A~1B
Figure 2A~2C
Figure 3~4A
AI summary
Methods and nodes, for assignment of uplink control channel resources for providing HARQ feedback for data transmitted on a downlink data channel associated with a downlink control channel. The downlink control channel comprises at least a set of downlink control channel resources, which is configurable over a subset of available time frequency resources. The method comprises dividing the set of downlink control channel resources into at least two subsets of references, comprising indices to the respective downlink control channel resources. Also, the method comprises defining, for each such subset of references, an associated subset of references comprising indices to unique uplink control channel resources. Furthermore, the method comprises associating each element in the subset of references with a subframe and an element in the subset of references. Additionally, the method further comprises transmitting data on the downlink data channel associated with the downlink control channel.