3D Beamforming via Uplink Channel Estimation
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Solution Overview
Problem
Base stations face challenges in estimating vertical channel information and forming three-dimensional beams without direct feedback from terminals, particularly in frequency division duplex (FDD) systems, which limits the effectiveness of full-dimension multi-input multi-output (FD-MIMO) technology and reduces network capacity.
Innovation Solution
A method and device that enable a base station to estimate vertical channel information using uplink signals, determining directivity information for vertical channels and performing resource scheduling and beamforming based on both vertical and horizontal channel information, allowing for three-dimensional beamforming without requiring direct feedback from terminals.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the base station uses traditional two-dimensional beamforming without vertical channel information, then the device complexity is reduced, but the signal quality and network capacity are limited
Solution Approach 1:
The patent uses uplink channel information as an intermediary to estimate downlink vertical channel characteristics. Instead of directly acquiring downlink vertical channel information (which would require complex terminal feedback mechanisms), the base station leverages the reciprocal relationship in TDD systems to use uplink channel estimates as a proxy for downlink channel estimation, thereby improving signal quality without significantly increasing system complexity
Solution Approach 2:
The patent creates a copy of vertical channel information by estimating downlink vertical channel characteristics from uplink channel measurements. This copying approach allows the base station to obtain necessary vertical beamforming parameters without requiring terminals to perform and feedback complex three-dimensional channel measurements, thus maintaining low device complexity while improving signal quality
2Measurement precision
If the base station acquires vertical channel information directly from terminals, then the three-dimensional beamforming accuracy is improved, but the ease of operation is reduced due to requiring terminal support and feedback
Solution Approach 1:
The patent inverts the traditional approach by having the base station estimate vertical channel information from uplink signals rather than having terminals measure and feedback downlink channel information. This inversion eliminates the need for terminal support for three-dimensional beamforming and complex feedback mechanisms, thereby maintaining ease of operation while achieving accurate vertical channel estimation through the reciprocity of TDD channels
3Productivity
If the base station implements full three-dimensional beamforming with terminal feedback, then the network capacity is increased, but the device complexity and terminal requirements are significantly increased
Solution Approach 1:
The patent uses uplink channel information as an intermediary to obtain vertical channel characteristics needed for three-dimensional beamforming. This approach enables the base station to perform spatial multiplexing and increase network capacity without requiring terminals to implement complex three-dimensional channel measurement and feedback capabilities, thus increasing productivity while controlling device complexity
Solution Approach 2:
The patent makes the uplink channel measurement serve multiple functions: it is used for both uplink communication and as a source for estimating downlink vertical channel information for beamforming. This multi-functionality allows the system to achieve three-dimensional beamforming capabilities and increased network capacity without adding separate measurement and feedback mechanisms, thereby increasing productivity without proportionally increasing device complexity
Data Source
AI summary
The present invention relates to a method and a device for beamforming, and, more particularly, to a method and a device for transmitting a downlink signal by using a two-dimensional active array antenna in a wireless communication system. In order to achieve the objective mentioned above, a beamforming method by a base station in a mobile communication system, according to one embodiment of the present invention, comprises the steps of: receiving an uplink signal from at least one terminal; determining directivity information of a vertical channel of a downlink for the at least one terminal on the basis of the uplink signal; and performing resource scheduling and beamforming for the at least one terminal on the basis of the directivity information of the vertical channel of the downlink and channel status information in a horizontal direction received from the at least one terminal. According to an embodiment of the present invention, since a base station can estimate vertical channel information by using an uplink signal, it is possible to provide three-dimensional beamforming to terminals even without receiving the vertical channel information directly from the terminals, and thus the signal quality of each user can be improved and the efficiency of spatial multiplexing in a cell can be increased to thereby increase the total network capacity.