Dual-Stage PMI Codebook for 2D Antenna Array CSI Reporting
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Solution Overview
Problem
Existing channel quality reporting processes in wireless communication systems do not adequately accommodate the reporting of channel state information associated with large two-dimensional array transmit antennas, which are common in full-dimension MIMO systems, leading to inefficiencies in radio interface efficiency and coverage.
Innovation Solution
The design of codebooks and signaling methods for user equipment (UE) and base stations to efficiently calculate and transmit channel state information (CSI) using precoding matrix indicators (PMIs), including configuration information for CSI reporting, channel quality indicators (CQI), and rank indicators (RI), to support two-dimensional antenna arrays.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If existing channel quality reporting processes are used, then the system maintains simplicity in reporting mechanisms, but the system fails to adequately accommodate reporting of channel state information associated with large two-dimensional array transmit antennas
Solution Approach 1:
The precoding matrix indicator (PMI) is segmented into a first PMI and a second PMI. The first PMI indexes a first precoding matrix from a codebook, while the second PMI indexes a second precoding matrix from another codebook. This segmentation allows the system to handle complex 2D antenna array configurations by breaking down the single complex PMI into two simpler, manageable components that can independently represent different dimensions of the antenna array.
Solution Approach 2:
The invention extends the traditional single-dimension PMI concept into a two-dimensional structure by introducing two separate PMIs. This dimensional expansion enables the system to accommodate two-dimensional antenna arrays by mapping the spatial dimensions of the antenna elements to the two PMI components, thereby enhancing adaptability without proportionally increasing overall system complexity.
2Measurement precision
If detailed channel state information is reported for 2D antenna arrays, then the accuracy of channel quality reporting improves, but the feedback overhead increases
Solution Approach 1:
Instead of reporting complete channel state information for all antenna elements, the system uses two PMIs that partially represent the precoding information. The first PMI provides coarse-grained information about the overall precoding structure, while the second PMI provides fine-grained adjustments. This partial action approach achieves sufficient reporting accuracy for 2D arrays without transmitting excessive data, thereby reducing feedback overhead while maintaining measurement precision.
Data Source
Figure 1
Figure 2A~2B
Figure 3A
AI summary
A UE includes at least one transceiver and at least one processor operably connected to the at least one transceiver for receiving configuration information for a CSI reporting via an RRC signaling, identifying a first PMI of a dual-stage codebook based on the configuration information for the CSI reporting; and transmitting the first PMI on an uplink channel, wherein the first PMI includes a first index for a first dimension and a second index for a second dimension if each of the number of one or more antenna ports in the first dimension and the number of one or more antenna ports in the second dimension is greater than one, and wherein the first PMI includes one codebook index if one of the number of one or more antenna ports in the first dimension and the number of one or more antenna ports in the second dimension equals one.