Dynamic HARQ-ACK Resource Allocation via Offset Parameters
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Solution Overview
Problem
In 3GPP networks, the dynamic resource allocation for HARQ-ACK transmission on enhanced physical downlink control channels (ePDCCH) is not adequately addressed, leading to resource allocation collisions due to the same lowest CCE index being used for both legacy PDCCH and ePDCCH, which limits capacity and increases inter-cell interference.
Innovation Solution
The solution involves determining the uplink resource allocation for PUCCH based on the lowest control channel element index (CCE) and enhanced control channel element index (eCCE), along with user equipment-specific starting offsets and additional offset-related parameters, using an ACK/NACK resource offset (ARO) to avoid collisions, and employing subframe stacking and transmit power control for coordinated multipoint scenarios.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If the lowest CCE index is used for dynamic resource allocation of PUCCH, then the resource allocation is simple and unique per UE, but resource allocation collisions occur when both legacy PDCCH and ePDCCH use the same lowest CCE index
Solution Approach 1:
The patent changes the parameter used for resource allocation from the lowest CCE index alone to a combination of the lowest CCE index and an offset value. This parameter modification allows the system to maintain the simplicity of index-based allocation while avoiding collisions by introducing an additional degree of freedom through the offset parameter, which can be dynamically adjusted based on whether ePDCCH or legacy PDCCH is used.
Solution Approach 2:
The offset value acts as an intermediary between the CCE index and the final PUCCH resource allocation. It mediates the conflict between legacy PDCCH and ePDCCH by providing an additional layer of resource differentiation, allowing both systems to coexist without collision while maintaining their respective allocation mechanisms.
2Productivity
If ePDCCH is introduced to increase PDCCH capacity, then more UEs can be served, but resource allocation complexity increases due to the need to differentiate between legacy PDCCH and ePDCCH allocations
Solution Approach 1:
The patent modifies the resource allocation parameters by introducing an offset value that is added to the lowest CCE index. This parameter change enables the system to support both legacy PDCCH and ePDCCH with differentiated resource allocations, thereby increasing overall PDCCH capacity while maintaining a relatively simple allocation mechanism based on modified index arithmetic.
Solution Approach 2:
The enhanced resource allocation mechanism serves multiple functions: it supports both legacy PDCCH and ePDCCH allocations, provides collision avoidance, and enables dynamic resource differentiation. This multi-functional approach increases system capacity without requiring entirely separate allocation mechanisms for different PDCCH types.
3Productivity
If CRS is removed or reduced to increase DL throughput and save network energy, then DL throughput increases and energy consumption decreases, but the capacity for CRS-based PDCCH is limited
Solution Approach 1:
The ePDCCH with enhanced resource allocation acts as an intermediary that compensates for the reduced CRS-based PDCCH capacity. By introducing a new control channel with its own resource allocation mechanism (based on eCCE indices and offsets), the system maintains or enhances overall PDCCH capacity even when CRS resources are reduced for throughput optimization.
Solution Approach 2:
The patent changes the fundamental parameters of control channel resource allocation by moving from CRS-based PDCCH to ePDCCH with eCCE-based indexing. This parameter transformation allows the system to decouple PDCCH capacity from CRS resources, enabling DL throughput optimization through CRS reduction while maintaining PDCCH capacity through the alternative ePDCCH mechanism.
Data Source
AI summary
Embodiments of a system and method for providing dynamic hybrid automatic repeat request-acknowledgement (HARQ-ACK) transmission with enhanced physical downlink control channels are generally described herein. In some embodiments, a receiver is arranged to receive, on an enhanced physical downlink control channel (ePDCCH), one of a lowest control channel element index (nCCE) and a lowest enhanced control channel element index (neCCE), a user equipment specific starting offset (NPUCCH(1)) and at least one additional offset-related parameter. A processor determines allocation of an uplink resource of a physical uplink control channel (PUCCH) for HARQ-ACK transmission based the one of a lowest control channel element index (nCCE) and a lowest enhanced control channel element index (neCCE), the user equipment specific starting offset (NPUCCH(1)) and at least one selected from the at least one additional offset-related parameter. A transmitter transmits a signal on the PUCCH using the allocated uplink resource.