PUCCH Resource Allocation for HARQ-ACK in eIMTA Wireless Systems
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Solution Overview
Problem
In wireless communication systems, transmitting HARQ-ACKs efficiently while avoiding collisions between Physical Uplink Control Channel (PUCCH) resources, especially when Enhanced Interference Mitigation and Traffic Adaptation (eIMTA) is configured for User Equipment (UE), is a challenge due to the complexity of resource allocation and interference management.
Innovation Solution
The method involves determining PUCCH resources using an HARQ-ACK Resource Offset (ARO) to shift resources for subframes, ensuring that PUCCH resources for eIMTA and non-eIMTA UEs are allocated contiguously or offset to prevent collisions, with ARO values calculated based on the number of Enhanced Control Channel Elements (ECCEs) in the EPDCCH PRB sets, allowing efficient use of resources across different subframe sets.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If PUCCH resources are allocated for multiple downlink subframes in eIMTA systems, then HARQ-ACK transmission capability is improved, but PUCCH resource collision between eIMTA and non-eIMTA UEs occurs
Solution Approach 1:
The patent divides downlink subframes into two distinct sets: a first subframe set common to both eIMTA and non-eIMTA UEs, and a second subframe set specific to eIMTA UEs. This segmentation allows separate PUCCH resource allocation strategies for each set, preventing resource collisions while maintaining high HARQ-ACK transmission capability. The ARO parameter is applied differently to each subframe set to achieve orthogonal resource allocation.
Solution Approach 2:
The patent applies different ARO values to different subframe sets based on their specific requirements. The first subframe set uses one ARO configuration optimized for compatibility with non-eIMTA UEs, while the second subframe set uses a different ARO configuration optimized for eIMTA-specific operations. This local differentiation resolves the contradiction by tailoring resource allocation to each subframe set's characteristics.
2Adaptability or versatility
If ARO is used to shift PUCCH resources for first subframe set, then resource allocation flexibility is improved, but resource waste occurs when shifting to preceding subframes
Solution Approach 1:
The patent implements dynamic ARO adjustment based on the specific composition of downlink subframes. When the downlink subframes include only the first subframe set, a first ARO value is applied that shifts resources optimally without waste. When the second subframe set is also present, a second ARO value is applied that prevents resource collision. This dynamic adaptation resolves the contradiction by adjusting resource allocation flexibility to match actual system conditions.
Solution Approach 2:
The patent changes the ARO parameter value based on the presence or absence of the second subframe set. By modifying this key parameter dynamically, the system achieves optimal resource allocation flexibility while preventing resource waste. The parameter change allows the same resource allocation mechanism to serve different operational scenarios efficiently.
3Reliability
If separate PUCCH resources are allocated for second subframe set, then eIMTA UE performance is improved, but overall resource utilization efficiency deteriorates
Solution Approach 1:
The patent merges the resource allocation mechanisms for both subframe sets under a unified framework using ARO. Instead of completely separate resource pools, the system uses a single PUCCH resource pool with differentiated ARO applications. This merging approach ensures reliable eIMTA UE transmission while maintaining high overall resource utilization efficiency by eliminating redundant resource allocations.
Data Source
AI summary
According to one embodiment of the present invention, a method for transmitting a hybrid automatic repeat request (HARQ)-ACK in a wireless communication system, comprises the steps of: determining a physical uplink control channel (PUCCH) resource for a plurality of downlink subframes using a HARQ-ACK resource offset (ARO); and transmitting HARQ-ACK from one uplink subframe via the PUCCH resource.