Hybrid Full-Dimensional MIMO Precoding Segmentation
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Solution Overview
Problem
Current wireless communication systems, particularly in LTE-Advanced, face challenges in designing effective MIMO precoding and CSI feedback due to the limited number of antenna ports supported, which is insufficient for large antenna arrays, leading to inefficiencies in beamforming and channel state information management.
Innovation Solution
The implementation of hybrid full-dimensional MIMO systems that split the precoding design into open-loop and closed-loop components, using a two-dimensional antenna array to virtualize multiple antenna elements into a smaller number of ports, allowing for effective channel estimation and precoding matrix determination based on channel state information and user equipment-specific reference signals.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the number of antenna ports is increased to support large antenna arrays, then the beamforming efficiency and MIMO performance are improved, but the device complexity and channel state information feedback overhead increase
Solution Approach 1:
The patent segments the precoding design into two independent parts: a first precoding matrix (W1) configured by higher layers with a codebook of larger dimensions, and a second precoding matrix (W2) determined by UE based on channel state information with a codebook of smaller dimensions. This segmentation allows the system to handle large antenna arrays by dividing the complex precoding task into manageable parts, improving beamforming efficiency while controlling device complexity.
Solution Approach 2:
The patent introduces a new dimension in the codebook design by configuring a first codebook with a number of codebooks larger than traditionally supported. This dimensional expansion allows the system to accommodate large antenna arrays (e.g., 8Tx, 12Tx, 16Tx) by providing sufficient precoding matrix options in the codebook, thereby improving MIMO performance without being constrained by previous port limitations.
2Productivity
If the number of antenna ports is increased to support large antenna arrays, then the MIMO performance is improved, but the channel state information feedback overhead increases
Solution Approach 1:
The patent segments the precoding matrix into W1 (configured by higher layers) and W2 (determined by UE based on CSI). This segmentation reduces feedback overhead because the UE only needs to feedback information related to W2 selection, while W1 is configured through higher layer signaling. This allows the system to support large antenna arrays and improved MIMO performance without proportionally increasing CSI feedback overhead.
3Productivity
If a two-dimensional antenna array is used to virtualize multiple antenna elements, then the beamforming efficiency is improved, but the signal processing complexity increases
Solution Approach 1:
The patent segments the precoding operation into two stages: W1 provides coarse beamforming directions configured by higher layers, while W2 provides fine-grained adjustments determined by UE based on instantaneous channel conditions. This segmentation enables efficient handling of two-dimensional antenna arrays by breaking down the complex signal processing into manageable stages, improving beamforming efficiency while controlling signal processing complexity.
Data Source
AI summary
According UE is configured to receive a channel state information reference signal (CSI-RS) from an evolved Universal Terrestrial Radio Access Network (E-UTRAN) Node B (eNB), determine channel state information based on the CSI-RS, and send the channel state information to the eNB. The channel state information includes a precoding matrix indicator corresponding to a first precoding matrix. The UE is also configured to receive a UE specific reference (UE-RS) signal and a physical downlink shared channel (PDSCH) signal. The UE-RS is precoded with a second precoding matrix. The UE estimates a UE-RS effective channel including the second precoding matrix based on the UE-RS and decodes data from the PDSCH signal based on an the first precoding matrix and the UE-RS effective channel.