Self-Contained HARQ Subframe Structure for 5G Latency
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Solution Overview
Problem
Current wireless communication systems face challenges in reducing Hybrid Automatic Repeat Request (HARQ) acknowledgement latency and supporting diverse user equipment (UE) capabilities, particularly in 5G systems, where efficient HARQ feedback mechanisms are needed to balance latency and power consumption.
Innovation Solution
The implementation of a self-contained HARQ ACK-NACK transmission scheme in 5G systems, which allows HARQ feedback to be transmitted in the same subframe, and a relaxed HARQ ACK-NACK transmission scheme with flexible delays, enabling dynamic scheduling based on UE capabilities and power consumption considerations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of time
If HARQ feedback is transmitted in the same subframe (self-contained scheme), then HARQ latency is reduced, but UE power consumption increases
Solution Approach 1:
The system dynamically switches between self-contained HARQ scheme (for low latency requirements) and relaxed HARQ scheme (for power saving), allowing flexible adaptation based on traffic conditions and UE capabilities. The network can configure different HARQ feedback timing scenarios to balance latency and power consumption.
Solution Approach 2:
The invention introduces configurable parameters including HARQ feedback timing offset, subframe structure configuration, and UE capability indicators that allow the system to adjust HARQ operation mode. By changing these parameters, the system can optimize between latency and power consumption based on specific service requirements.
2Loss of time
If self-contained subframe structure is implemented, then HARQ latency is reduced for critical communications, but system complexity increases
Solution Approach 1:
The subframe is segmented into distinct functional parts: downlink data transmission portion and uplink HARQ feedback portion. This segmentation allows independent optimization of each part and simplifies the overall system design by clearly separating transmission and feedback functions within the same subframe.
Solution Approach 2:
The self-contained subframe structure serves multiple functions: it carries downlink data, provides uplink HARQ feedback, and supports both self-contained and relaxed HARQ schemes. This multi-functionality reduces the need for separate dedicated feedback subframes, thereby managing system complexity while providing low-latency HARQ operation.
3Use of energy by moving object
If flexible HARQ feedback delays are supported, then power-saving modes are enabled, but scheduling complexity increases
Solution Approach 1:
The system uses configurable timing offset parameters to define flexible HARQ feedback delays. By adjusting these parameters based on UE power saving modes and traffic conditions, the network can enable power-saving operation while managing scheduling complexity through standardized parameter sets.
Solution Approach 2:
The HARQ feedback timing is made dynamic, allowing the system to adjust feedback delay based on UE capability indicators and power saving mode configurations. This dynamic adaptation enables power-saving modes for UEs that can tolerate longer delays, while maintaining responsive HARQ for UEs requiring lower latency.
Data Source
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AI summary
Technology for a user equipment (UE) operable to perform hybrid automatic repeat request (HARQ) acknowledgement (ACK)-negative acknowledgement (NACK) transmissions is disclosed. The UE can generate a UE capability information message for transmission to an eNodeB. The UE capability information message can indicate that the UE supports a self-contained HARQ ACK-NACK transmission scheme that uses a self- contained subframe structure. The UE can signal a transceiver at the UE to send a request to use the HARQ ACK-NACK transmission scheme. The UE can process an indication received from the eNodeB in response to the request. The indication can configure the UE to use the self-contained HARQ ACK-NACK transmission scheme to perform HARQ ACK-NACK transmissions.