Multi-branch NOMA DCI Format for HARQ Acknowledgement
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Solution Overview
Problem
Current 5G NR technologies face inefficiencies in data transmission due to lack of support for multi-branch Non-Orthogonal Multiple Access (NOMA) and inadequate acknowledgement/negative acknowledgement (ACK-NACK) mechanisms in existing Downlink Control Information (DCI) formats, leading to increased control overhead and limited HARQ processing capabilities.
Innovation Solution
A new DCI format is introduced to support multi-branch NOMA transmission, enabling multiple ACK/NACKs within a single DCI and allowing explicit acknowledgement from the base station without a HARQ ID field, along with the use of Autonomous Uplink Downlink Feedback Information (AUL-DFI) to enhance Licensed Assisted Access (LAA) by employing a bitmap for HARQ process IDs.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If existing DCI formats are used for HARQ acknowledgement, then the system maintains compatibility with current 5G NR standards, but control overhead increases and HARQ processing capabilities are limited
Solution Approach 1:
The patent segments the HARQ acknowledgement process by introducing separate indicator fields for different transmission types (first indication field for scheduled transmission, second indication field for grant-free transmission). This segmentation allows independent optimization of each transmission type's acknowledgement mechanism, reducing overall control overhead while maintaining comprehensive HARQ processing capability.
Solution Approach 2:
The patent adds a new dimension to the DCI structure by incorporating grant-free transmission indication fields alongside the traditional scheduled transmission fields. This dimensional expansion enables the system to handle multiple transmission types within a unified DCI framework, improving HARQ processing capability without proportionally increasing control overhead.
2Productivity
If multi-branch NOMA transmission is supported, then system throughput increases, but existing DCI formats become inadequate requiring new formats
Solution Approach 1:
The patent creates a universal DCI format that serves multiple functions: it handles both scheduled and grant-free transmissions, supports both single-branch and multi-branch NOMA transmissions, and provides acknowledgement for multiple HARQ processes. This multi-functionality enables multi-branch NOMA transmission support without requiring entirely new DCI formats for each scenario, thus increasing system throughput while controlling format complexity.
Solution Approach 2:
The patent introduces dynamic indication fields that can adaptively indicate different transmission types and parameters based on current system conditions. The first and second indication fields can dynamically switch between indicating scheduled and grant-free transmissions, allowing the DCI format to flexibly support multi-branch NOMA when needed while maintaining compatibility with traditional modes, thereby improving throughput without permanent complexity increase.
Data Source
AI summary
In a Non-Orthogonal Multiple Access (NOMA) system, a user equipment (UE) can be configured to transmit signals with multiple access (MA) signatures. If a base station configures multiple MA signatures to a UE, the UE can select one or more MA signatures, then transmit signals in parallel, serial, or in hybrid ways. Due to the flexibility and complexity of the UE selecting MA signatures without an explicit configuration from the base station, additional control overhead is provided to support parallel HARQ processing. In addition, a new DCI format is disclosed that supports multi-branch NOMA transmission, which allows multiple ACK/NACKs within a DCI. Further, using the techniques disclosed herein, a base station can explicitly indicate ACK-NACKs without being assisted by a HARQ ID field.