DMRS Configuration for 5G Small Data Transmission
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Solution Overview
Problem
Current wireless communication systems face challenges in efficiently configuring demodulation reference signals (DMRS) for configured grant-based small data transmission (CG-SDT) in 5G new radio (NR) networks, particularly in scenarios where traditional random access procedures are not necessary.
Innovation Solution
The proposed solution involves configuring one or two DMRS sequences for CG-SDT operations, determining the DMRS resource index through mapping between synchronization signal blocks (SSBs) and CG-PUSCH resources, and using these configurations for direct data transmission on the physical uplink shared channel (PUSCH) without associated PRACH preamble transmission.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If traditional random access procedures are used for data transmission, then connection establishment is reliable, but data transmission delay increases
Solution Approach 1:
The network pre-configures uplink resources and DMRS parameters for small data transmissions before the UE needs to send data. When data needs to be transmitted, the UE can directly use the pre-configured resources without going through random access procedures, thereby reducing delay while maintaining reliability through proper DMRS configuration for channel estimation.
Solution Approach 2:
The patent extracts and separates small data transmission from the traditional random access procedure. By identifying specific scenarios where small data transmission is needed, the system creates a dedicated configured grant-based transmission path that bypasses the random access procedure, reducing delay for these specific cases while keeping the traditional procedure intact for other scenarios.
2Loss of time
If configured grant-based transmission is implemented, then data transmission delay is reduced, but DMRS configuration complexity increases
Solution Approach 1:
The patent modifies DMRS parameters specifically for configured grant-based small data transmission, including DMRS sequence initialization, resource index mapping, and port configuration. These parameter changes enable efficient DMRS configuration that supports the delayed transmission requirements while managing complexity through standardized parameter sets.
Solution Approach 2:
The DMRS configuration is segmented into different scenarios and transmission types. The patent defines specific DMRS configurations for configured grant-based small data transmission that are separate from traditional random access procedures, allowing optimized parameters for each scenario without increasing overall system complexity.
3Measurement precision
If DMRS sequences are properly configured for CG-SDT, then channel estimation accuracy is improved, but signaling overhead increases
Solution Approach 1:
The patent configures DMRS sequences to serve multiple functions: channel estimation for demodulation, implicit indication of transmission parameters, and support for both random access and configured grant scenarios. This multi-functionality reduces the need for separate signaling for each purpose, thereby reducing overall signaling overhead while maintaining estimation accuracy.
Data Source
AI summary
A computer-readable storage medium stores instructions to configure a UE for a configured grant-based small data transmission (CG-SDT) in the 5G NR network. A plurality of SSBs transmitted from a base station using a corresponding plurality of transmit beams is decoded. An SSB of the plurality of SSBs is selected based on signal strength for each of the plurality of transmit beams. A DMRS resource index is determined for a DMRS resource based on a mapping of the SSB and the DMRS resource. A DMRS sequence is determined based on the DMRS resource index. Uplink data is encoded for a CG physical uplink shared channel (CG-PUSCH) transmission with the DMRS sequence during a PUSCH occasion configured by the base station.