SPS HARQ-ACK Scheduling in Flexible Duplex TDD Nodes
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Solution Overview
Problem
Existing NR systems face inefficiencies in resource utilization and increased latency due to half-duplex mode in TDD spectrum, which limits flexibility and interferes with HARQ-ACK transmission in SPS PDSCH.
Innovation Solution
Implementing a flexible duplex mode that allows for delayed transmission of SPS HARQ-ACK by overlapping PUCCH and first-type symbols, with information blocks determining downlink symbols and subbands to optimize resource allocation and reduce latency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If half-duplex mode is used in TDD spectrum, then self-interference is avoided and cross-link interference is alleviated, but resource utilization rate decreases and latency increases
Solution Approach 1:
The patent applies dynamic TDD configuration where the base station can flexibly switch between half-duplex and full-duplex modes based on traffic conditions and interference levels. The network can dynamically adjust the duplex mode for different cells and time periods, transforming the static half-duplex system into a dynamic one that adapts to changing requirements, thereby improving resource utilization while maintaining interference avoidance when needed.
Solution Approach 2:
The patent changes the operational parameters of the TDD system by introducing flexible duplex mode configuration. The base station can modify the duplex mode parameter (half-duplex or full-duplex) based on network conditions, allowing the system to transition from fixed parameter operation to variable parameter operation, thus resolving the contradiction between reliability and productivity.
2Reliability
If half-duplex mode is used in TDD spectrum, then self-interference is avoided and cross-link interference is alleviated, but latency increases
Solution Approach 1:
The dynamic switching capability allows the system to use full-duplex mode when low latency is critical and interference conditions permit, thereby reducing the time loss associated with half-duplex mode's sequential transmission. This dynamic adaptation directly addresses the latency issue while preserving interference avoidance strategies when applicable.
Solution Approach 2:
By changing the duplex mode parameter from fixed half-duplex to flexible configuration, the system can adjust transmission timing and mode to minimize latency. The network can select full-duplex operation for time-sensitive traffic, effectively reducing the time loss that characterizes half-duplex systems.
3Productivity
If flexible duplex mode is implemented, then resource utilization improves and latency reduces, but HARQ-ACK transmission for SPS PDSCH becomes complex
Solution Approach 1:
The patent introduces an intermediary mechanism where the base station explicitly indicates the duplex mode and PUCCH resource allocation through DCI signaling. This intermediary information layer mediates between the flexible duplex mode operation and the HARQ-ACK transmission process, providing clear guidance to UEs on how to transmit acknowledgments despite the flexibility in duplex configuration, thereby reducing the perceived complexity at the UE side.
Solution Approach 2:
The base station performs preliminary configuration of PUCCH resources and duplex modes through higher-layer signaling and DCI indications before HARQ-ACK transmission is needed. This preliminary action prepares the system in advance, so when HARQ-ACK transmission occurs in flexible duplex mode, the UE already has the necessary resource allocation information, reducing the complexity of real-time decision-making.
4Productivity
If flexible duplex mode is implemented, then resource utilization improves and latency reduces, but hardware complexity increases
Solution Approach 1:
The patent designs the flexible duplex mode system with universal hardware capabilities that can operate in both half-duplex and full-duplex modes. The base station and UE are equipped with multi-functional radio frequency chains and signal processing units that can adapt to different duplex configurations without requiring separate dedicated hardware for each mode, thereby reducing the hardware complexity increase that would otherwise result from flexible operation.
Data Source
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AI summary
The present application discloses a method and an apparatus used in a node for wireless communication. A node receives a first information block and receives a second information block, the first information block being used to indicate a downlink symbol; and the node sends a first signal in a target time slot, the first signal being used for carrying HARQ-ACK bits comprised in a target HARQ bit set. The HARQ-ACK bits comprised in the target HARQ bit set belong to a first HARQ bit set, and the first HARQ bit set comprises HARQ-ACK bits for an SPS PDSCH. A first PUCCH resource is a PUCCH resource determined for the first HARQ bit set. The first PUCCH resource overlaps with one first-type symbol, and whether the downlink symbol indicated by the first information block belongs to the first-type symbol depends on the second information block. An SPS HARQ delay value corresponding to the target HARQ bit set is not less than a time interval length between the target time slot and a receiving time slot of the corresponding SPS PDSCH. By means of the present application, the delay is reduced.