Multi-TTI PUSCH Scheduling via Single DCI in Unlicensed Bands
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Solution Overview
Problem
Current 5G NR (New Radio) systems face challenges in efficiently scheduling multiple Physical Uplink Shared Channel (PUSCH) transmissions over multiple Transmit Time Intervals (TTIs) in unlicensed bands, due to the need for multiple Listen-Before-Talk (LBT) procedures for each DCI (Downlink Control Information) message.
Innovation Solution
The implementation of multi-TTI PUSCH transmission scheduling using a single DCI format, which allows for the allocation of time domain resources and supports code block group (CBG) based hybrid automatic repeat request (HARQ) operations, enabling efficient resource utilization in unlicensed bands.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If multiple DCI messages are used to schedule multiple PUSCH transmissions in unlicensed bands, then each transmission can be independently controlled, but the number of LBT procedures increases and DCI overhead increases
Solution Approach 1:
The patent combines multiple PUSCH transmission scheduling into a single DCI message, where one DCI message can schedule multiple PUSCH transmissions across multiple TTIs. This merging approach reduces the number of LBT procedures from multiple separate LBT calls (one per DCI message) to a single LBT procedure, while still maintaining independent control of each transmission through separate time domain resource allocation entries within the same DCI message.
Solution Approach 2:
The DCI message structure is enhanced to serve multiple functions simultaneously: it schedules multiple PUSCH transmissions, specifies different time domain resource allocations (single TTI or multi-TTI), and provides independent control parameters for each transmission. This multi-functional DCI message eliminates the need for separate DCI messages and LBT procedures for each transmission.
2Adaptability or versatility
If multiple DCI messages are used to schedule multiple PUSCH transmissions, then scheduling flexibility is maintained, but DCI message overhead increases
Solution Approach 1:
Multiple scheduling decisions that would traditionally require separate DCI messages are merged into a single DCI message. The time domain resource allocation field can indicate multiple entries, each corresponding to a different PUSCH transmission time, thereby reducing the total number of DCI messages transmitted and the cumulative overhead associated with them.
Solution Approach 2:
The time domain resource allocation field is segmented into multiple entries within a single DCI message, where each entry can independently specify different time domain resources, mapping types, and transmission parameters. This segmentation allows flexible scheduling of multiple PUSCH transmissions without requiring separate DCI messages, thus reducing overall overhead while maintaining scheduling flexibility.
3Productivity
If a single DCI message schedules multiple PUSCH transmissions across multiple TTIs, then LBT procedures are minimized and overhead is reduced, but the DCI message structure becomes more complex
Solution Approach 1:
The DCI message structure is segmented into standardized fields, including a time domain resource allocation field that can contain multiple entries. Each entry follows a consistent format with parameters like starting TTI, length, and mapping type. This segmentation approach organizes the complexity into a systematic structure that can be processed efficiently by both transmitter and receiver while enabling multiple PUSCH transmissions to be scheduled in a single DCI message.
Solution Approach 2:
The DCI message includes pre-configured time domain resource allocation entries that are prepared in advance according to RRC-configured tables. The starting TTI, length, and mapping type are predetermined and signaled efficiently, allowing the receiver to prepare for multiple PUSCH transmissions without requiring complex real-time processing. This preliminary configuration reduces the processing complexity when executing the scheduled transmissions.
Data Source
AI summary
Apparatuses, systems, and methods for a user equipment device (UE) to perform multiple TTI PUSCH transmissions in a wireless communication system as well as code block groups (CBGs) based retransmissions operations. A UE may perform radio resource control (RRC) signaling with a network entity to configure a data structure that may include one or more sets of physical uplink shared channel (PUSCH) transmission configurations, where each set of PUSCH transmission configurations span multiple TTIs. The wireless device may be configured to receive, from the network entity, a downlink control information (DCI) message that may include a time domain resource assignment field (TDRA) that may indicate a set of PUSCH transmission configurations included in the data structure. The wireless device may perform PUSCH transmissions spanning multiple TTIs according to the indicated set of PUSCH transmission configurations over an unlicensed band.