Adaptive HARQ-ACK Timing and Buffer Management for 5G
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Solution Overview
Problem
Next generation 5G new radio (NR) systems face challenges in achieving low-latency and high-performance services due to the need for shorter HARQ-ACK timing, which increases processing demand and may sacrifice UE throughput, especially given hardware limitations and power consumption constraints.
Innovation Solution
An adaptive Hybrid Automatic Repeat Request (HARQ) operation scheme is introduced, featuring adaptive HARQ-ACK feedback timing and an adaptive number of HARQ processes with a fixed HARQ soft buffer size, allowing UE to signal its capabilities and configure optimal HARQ-ACK timings and process numbers based on network configurations to balance low-latency and high-performance requirements.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of time
If HARQ-ACK timing is shortened to achieve low-latency services, then latency is reduced, but processing demand increases and UE throughput may be sacrificed
Solution Approach 1:
The patent implements dynamic HARQ-ACK timing adaptation where the timing can be adjusted based on UE capability and service requirements. The system supports multiple HARQ-ACK timing options (e.g., timing values of 2, 3, or 4 slots) and can dynamically select appropriate timing values through RRC configuration and DCI signaling, allowing the system to optimize between latency and processing capability demands in real-time
Solution Approach 2:
The patent changes the parameter of HARQ-ACK timing value based on different service types and UE capabilities. By configuring different timing values (k1 values) through higher-layer signaling and physical-layer signaling, the system can adapt the timing parameter to match specific service requirements (e.g., shorter timing for URLLC, longer timing for eMBB), thereby resolving the contradiction between latency reduction and processing capability
2Loss of time
If HARQ-ACK timing is shortened to achieve low-latency services, then latency is reduced, but UE throughput is sacrificed
Solution Approach 1:
The system dynamically adjusts HARQ-ACK timing based on service type and UE capability, allowing short timing for low-latency services when needed while using longer timing for throughput-optimized services. This dynamic adaptation ensures that UE throughput is not unnecessarily sacrificed across all services, only when specifically required for low-latency applications
Solution Approach 2:
By configuring different HARQ-ACK timing parameters (k1 values) through RRC and DCI signaling, the system can optimize the timing parameter for each specific service scenario, balancing latency requirements against throughput considerations based on the actual service needs
3Productivity
If the number of HARQ processes is increased to support high-performance services, then service performance is improved, but hardware cost increases due to larger HARQ soft buffer
Solution Approach 1:
The patent implements dynamic adaptation of the number of HARQ processes based on service requirements and UE capability. The system can configure different numbers of HARQ processes (e.g., 16 or 32) through RRC signaling and adaptively select appropriate process numbers for different service types, allowing the system to optimize between service performance and hardware resource usage in real-time
Solution Approach 2:
The system changes the parameter of HARQ process number based on service requirements and UE capability information. By configuring different process numbers through higher-layer signaling and adapting the actual number used through physical-layer signaling, the system can optimize the parameter to match specific service needs while controlling hardware resource consumption
Data Source
AI summary
An efficient Hybrid Automatic Repeat Request (HARQ) operation for low-latency and high-performance services in one radio access technology (RAT) in a wireless communication network is proposed. Under the proposed single HARQ operation scheme, an adaptive HARQ-ACK feedback timing is applied based on UE conditions and UE capability to support the tradeoff between low-latency and high-performance applications. In one embodiment, UE signals the network its HARQ-ACK timing capability. Furthermore, an adaptive number of HARQ processes is applied with a fixed HARQ soft buffer size because the hardware cost for HARQ soft buffer does not linearly increase with the number of HARQ processes. In one embodiment, UE determines a nominal HARQ soft buffer size and HARQ soft buffer size for each HARQ process based on a network-configured HARQ process number.