3D-MIMO Codebook Segmentation for Antenna Gain Control
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Solution Overview
Problem
In wireless communication systems, particularly in codebook-based 3D-MIMO, there is an increase in overhead associated with the transmission of reference signals and linear filter notifications as the number of transmission antenna elements increases, limiting the improvement in frequency use efficiency.
Innovation Solution
A base station and terminal apparatus with adjustable antenna gains in both horizontal and vertical directions, using a shared codebook that includes separate codebooks for horizontal and vertical antenna gains, to minimize overhead by precoding signals based on feedback control information.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the number of transmission antenna elements is increased to improve frequency use efficiency, then the transmission capacity is improved, but the overhead associated with reference signal transmission and linear filter notification increases
Solution Approach 1:
The codebook is divided into a first codebook and a second codebook. The first codebook contains linear filters for a first number of antenna elements, while the second codebook contains linear filters for a second number of antenna elements. This segmentation allows the system to select appropriate codebooks based on the actual number of antenna elements, thereby reducing the overhead associated with notifying all possible linear filters regardless of the actual antenna configuration.
Solution Approach 2:
The patent implements partial action by only notifying linear filters that are actually needed based on the number of transmission antenna elements. When the number of antenna elements is reduced, the system selectively notifies only the relevant subset of linear filters from the codebook, rather than notifying all possible linear filters. This partial notification approach reduces overhead while maintaining the capability to support larger antenna arrays when needed.
2Manufacturing precision
If separate codebooks are used for horizontal and vertical antenna gains, then the precision of antenna gain control is improved, but the device complexity increases
Solution Approach 1:
The patent merges the first codebook and second codebook into a unified codebook structure. The first codebook and second codebook are combined such that they form a single integrated codebook that can be selectively accessed. This merging reduces the overall complexity compared to maintaining completely separate codebook structures, while still preserving the ability to independently control horizontal and vertical antenna gains through the respective codebook portions.
Solution Approach 2:
The unified codebook structure serves multiple functions: it can operate with the first codebook when horizontal antenna elements are active, with the second codebook when vertical antenna elements are active, and can be selectively combined. This multi-functionality allows the same codebook structure to adapt to different antenna configurations and transmission scenarios, reducing the need for separate dedicated codebooks for each scenario.
Data Source
AI summary
A base station apparatus is capable of adjusting antenna gains in a horizontal direction and a vertical direction of the plurality of antennas included in the base station apparatus, by adjusting a phase and an amplitude of a signal addressed and transmitted to a terminal apparatus, stores a codebook which is shared with the terminal apparatus and describes a plurality of linear filters associated with antenna gains in the horizontal direction and antenna gains in the vertical direction, acquires control information indicating at least one out of a plurality of linear filters described in the codebook, of which notification is sent from the terminal apparatus, performs precoding on the signal addressed to the terminal apparatus, based on the control information and the first codebook, and transmits the signal subjected to the precoding.