Unified NR-U Reference Signal Design for Unlicensed Spectrum
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Solution Overview
Problem
In 5G NR systems, the independent design of Demodulation Reference Signals (DMRS) for PDCCH, PDSCH, and PBCH limits resource utilization, especially in unlicensed spectrum where Listen Before Talk (LBT) principles are used, making it challenging for terminal devices to effectively access channels due to restricted time-frequency resources.
Innovation Solution
A unified design of NR-U reference signals in the initial access subband of the unlicensed frequency band is proposed, allowing terminal devices to use reference signals according to their needs, enhancing resource utilization and LBT success chances by sending a first reference signal to assist channel quality estimation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If independent DMRS design for PDCCH, PDSCH, and PBCH is used, then each channel can have dedicated reference signals for accurate channel estimation, but resource utilization is reduced and terminal devices cannot perform joint channel estimation
Solution Approach 1:
The patent combines independent DMRS designs for PDCCH, PDSCH, and PBCH into a unified DMRS design. The network device transmits a unified DMRS that can be used for channel estimation across multiple channels, merging previously separate reference signal resources into a single shared resource that serves multiple purposes simultaneously.
Solution Approach 2:
The unified DMRS is designed to serve multiple functions: it can be used for channel estimation of PDCCH, PDSCH, and PBCH channels. The terminal device can selectively use the unified DMRS for different channels based on actual needs, making the reference signal universal rather than channel-specific, thereby improving resource utilization while maintaining estimation capability.
2Adaptability or versatility
If independent DMRS design with independent parameters is used, then each channel has optimized reference signal parameters, but terminal devices cannot perform joint estimation and resource utilization is reduced
Solution Approach 1:
The unified DMRS parameters are designed to be universally applicable across PDCCH, PDSCH, and PBCH channels. Instead of maintaining separate parameter sets for each channel, the patent uses a single set of parameters that works for all channels, reducing configuration complexity while enabling flexible joint estimation.
Solution Approach 2:
The patent modifies the parameter configuration by transitioning from multiple independent parameter sets to a single unified parameter set. This parameter change allows the terminal device to perform joint channel estimation across different channels using the same reference signal parameters, simplifying the overall system configuration while maintaining estimation flexibility.
3Productivity
If limited time-frequency resources are allocated for initial access in unlicensed spectrum, then LBT success chances are improved, but channel quality estimation capability is reduced
Solution Approach 1:
The patent merges the channel quality estimation function into the unified DMRS transmission. By combining reference signal transmission with channel estimation capability in a single resource allocation, the system achieves both efficient resource utilization for LBT and sufficient measurement precision for channel quality assessment within the limited time-frequency resources available in unlicensed spectrum.
Data Source
AI summary
The embodiments of the present application provide a signal transmission method, a transmitting end device, and a receiving end device. The method includes: sending, by a transmitting end device, a first reference signal to a receiving end device on a first subband. The first reference signal is a reference signal used to assist the receiving end device in estimating a channel quality of the first subband.