Configured Grant UCI Design for Spectral Efficiency in NOMA
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Solution Overview
Problem
In grant-free NOMA systems, the gNB faces challenges in identifying UE activity and determining which UE is transmitting data due to limited DMRS port numbers, and there is a need for adaptive MCS selection and reporting to improve spectral efficiency.
Innovation Solution
The solution involves UE transmitting configured grant UCI on the PUSCH with resource allocation indicated by the gNB through RRC configuration, using techniques like group-specific scrambling, symbol level spreading, and bit-level interleaving, and allowing the UE to autonomously select and report its MCS value through CG-UCI signaling.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If grant-free NOMA is used to improve spectral efficiency and reduce latency, then uplink transmission flexibility is improved, but gNB cannot identify UE activity or determine which UE is transmitting data
Solution Approach 1:
The patent introduces UCI (Uplink Control Information) as an intermediary signal that carries UE identification information along with data transmission. The UCI includes fields such as MCS (Modulation and Coding Scheme) and NDI (New Data Indicator) that enable the gNB to identify which UE is transmitting and what transmission parameters are being used, thereby resolving the identification problem in grant-free NOMA while maintaining spectral efficiency
Solution Approach 2:
The patent segments the UCI into multiple fields (MCS field, NDI field, etc.) that are separately encoded and transmitted. This segmentation allows the gNB to extract specific information (such as UE identity and transmission parameters) from different parts of the UCI structure, enabling reliable UE identification and parameter detection in grant-free NOMA scenarios
2Productivity
If adaptive MCS selection is implemented to improve spectral efficiency, then transmission performance is improved, but gNB needs to be notified of the MCS level used by the UE
Solution Approach 1:
The patent merges the MCS reporting function with the existing UCI structure by incorporating an MCS field directly into the UCI that is already being transmitted for other control purposes. This combining approach allows adaptive MCS selection to be implemented without requiring separate reporting mechanisms, thus improving spectral efficiency while minimizing additional overhead and complexity
Solution Approach 2:
The UCI structure is designed to serve multiple functions simultaneously: it carries UE identification information, transmission status (NDI), and adaptive MCS selection information. This multi-functionality allows a single signaling mechanism to address multiple requirements, reducing overall system complexity while enabling adaptive MCS selection for improved spectral efficiency
Data Source
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AI summary
Methods and apparatuses are described herein for uplink control information (UCI) design for uplink (UL) transmission with configured grants. In accordance with one embodiment, a wireless communications device may receive, from a gNB, first information indicating a plurality of resources for a configured grant (CG) on a physical uplink shared channel (PUSCH). The wireless communications device may determine, based on second information, a portion of the plurality of resources to use for transmitting a configured grant-uplink control information (CG-UCI). The wireless communications device may generate the CG-UCI, wherein the CG-UCI comprises at least one of: an identifier associated with the wireless communications device or an indication of a modulation and coding scheme (MCS). The wireless communications device may transmit, to the gNB on the PUSCH, the CG-UCI using the determined portion of the plurality of resources.