HARQ Feedback Control for Multicast PDSCH in NR
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Solution Overview
Problem
In wireless communication systems, particularly in New Radio (NR) technology, there is a challenge in efficiently managing hybrid automatic repeat request (HARQ) operations and acknowledging data transmissions across multiple physical downlink shared channels (PDSCHs) with different transmitting configuration indices (TCI states, especially for multicast broadcast services, where individual PUCCH resources allocation for each user equipment (UE) is complex and inefficient.
Innovation Solution
The method involves receiving physical downlink control channels (PDCCHs) that indicate HARQ operation status for each TCI state, allowing User Equipment (UE) to determine whether HARQ is enabled or disabled, and transmitting HARQ acknowledgments (ACK) only through PUCCH associated with enabled TCI states, while selecting PDSCHs based on reference signal measurements, and configuring PUCCH resources to match each TCI state for efficient data transmission.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If multiple PDSCHs with different TCI states are configured to carry the same transport block, then diversity reception and reliability are improved, but the complexity of HARQ management and PUCCH resource allocation increases
Solution Approach 1:
The patent segments the HARQ feedback mechanism by introducing a HARQ feedback indicator field in DCI that can independently enable or disable HARQ operations for each TCI state. This allows the system to divide the feedback management into manageable units per TCI state rather than handling all PDSCHs uniformly, thereby reducing overall complexity while maintaining reliability through selective HARQ operations.
Solution Approach 2:
The patent implements dynamic HARQ feedback control by allowing the network to flexibly enable or disable HARQ operations for specific TCI states through the HARQ feedback indicator field in DCI. This dynamic adjustment capability allows the system to adapt HARQ management complexity to actual transmission conditions, enabling simplified feedback for certain TCI states while maintaining robust HARQ operations for others, thus balancing reliability and complexity.
2Reliability
If HARQ operations are enabled for all TCI states, then data transmission reliability is improved, but uplink control channel resource consumption increases
Solution Approach 1:
The patent applies partial action by enabling HARQ operations only for specific TCI states that require it, rather than uniformly enabling HARQ for all TCI states. Through the HARQ feedback indicator field, the network can selectively activate HARQ feedback for certain TCI states while omitting it for others, thereby achieving the necessary reliability for critical transmissions while reducing overall PUCCH resource consumption.
Solution Approach 2:
The patent implements local quality control by allowing different HARQ operational characteristics for different TCI states based on their specific requirements. Each TCI state can be individually configured with HARQ enabled or disabled through the DCI's HARQ feedback indicator, enabling optimized resource consumption where HARQ is not needed while maintaining high reliability where it is essential.
3Measurement precision
If individual PUCCH resources are allocated for each UE in multicast broadcast service, then acknowledgment accuracy is improved, but resource allocation complexity increases
Solution Approach 1:
The patent applies universality by enabling a single DCI message to control HARQ feedback behavior across multiple TCI states for multiple UEs simultaneously. The HARQ feedback indicator field in the DCI provides a unified mechanism that can enable or disable HARQ operations for all monitored TCI states, eliminating the need for separate resource allocation procedures for each UE and thereby reducing allocation complexity while maintaining acknowledgment accuracy.
Data Source
AI summary
According to an embodiment of the present invention, a user equipment (UE) may receive one or more physical downlink control channels (PDCCHs) each carrying downlink control information (DCI) including a field indicating a transmitting configuration index (TCI) state, and receive, based the one or more PDCCHs, one or more of a plurality of physical downlink shared channels (PDSCHs), wherein the plurality of PDSCHs may carry a same transport block (TB) in a plurality of TCI states, respectively, and the UE can determine, for each TCI state, whether a hybrid automatic repeat request (HARQ) operation is enabled or disabled, and transmits HARQ-acknowledgement (ACK) information for the same TB through a physical uplink control channel (PUCCH) associated with an HARQ operation-enabled TCI state.