Reference Signal Configuration for Higher-Rank MU-MIMO
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Solution Overview
Problem
Current DMRS configurations in LTE/LTE-Advanced systems are inadequate for supporting higher-rank MIMO transmissions, particularly in massive MIMO scenarios, as they limit the number of layers to eight, leading to inefficiencies in spectral efficiency and MU-MIMO configuration flexibility.
Innovation Solution
The proposed method introduces a new data indicator (NDI) to differentiate between single-codeword and dual-codeword transmission modes, increasing the number of available state values in the DMRS configuration, allowing for the support of higher-rank MU-MIMO transmissions such as 16-layer or 24-layer configurations without increasing signaling overheads.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the number of layers is increased to support higher-rank MIMO transmissions, then spectral efficiency is improved, but the existing DMRS configuration becomes inadequate and cannot support more than eight layers
Solution Approach 1:
The invention segments the transmission modes into single-codeword and dual-codeword transmission modes, using different NDI values to differentiate between them. This segmentation allows the system to support higher-rank transmissions by providing distinct configuration spaces for different transmission types, thereby resolving the limitation of existing DMRS configurations that could only support up to eight layers.
2Adaptability or versatility
If a new DMRS configuration is introduced to support higher-rank transmissions, then configuration flexibility is improved, but signaling overhead increases
Solution Approach 1:
The invention makes the NDI field serve multiple functions: it not only indicates new data transmission but also differentiates between single-codeword and dual-codeword transmission modes. This multi-functionality allows the system to achieve enhanced MU-MIMO configuration flexibility without requiring additional signaling fields, thereby avoiding increased signaling overhead.
3Adaptability or versatility
If the DMRS configuration field is extended to accommodate more state values, then support for higher layers is improved, but control signaling complexity increases
Solution Approach 1:
The invention changes the interpretation of existing parameters (NDI values) to encode additional information about transmission modes. Instead of extending the DMRS configuration field, the system repurposes the NDI parameter to indicate whether single-codeword or dual-codeword transmission is used, thereby supporting higher layers without increasing control signaling structure complexity.
Data Source
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AI summary
According to embodiments of the present invention, a quantity of available state values of a reference signal configuration is increased by indicating a dual-codeword transmission mode and two single-codeword transmission modes, where the two single-codeword transmission modes are distinguished by using a new data indicator NDI. Therefore, higher-rank (such as 16-layer or 24-layer) MU-MIMO can be supported, increasing system spectral efficiency significantly, and improving MU-MIMO configuration flexibility and resource scheduling effectiveness.