FD-MIMO Precoding with Directional Segmentation
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Solution Overview
Problem
In Full-Dimension Multiple-Input Multiple-Output (FD-MIMO) systems, traditional linear and non-linear precoding techniques face challenges in effectively eliminating inter-user interference and noise, especially in strongly correlated channels, while also dealing with high computational complexity and reference signal overhead, particularly with a large number of users and antennas at the base station.
Innovation Solution
The proposed solution involves an electronic device that estimates channel correlation in multiple directions and adjusts the precoding scheme accordingly, using a hybrid approach that includes linear and non-linear precoding based on channel information feedback, employing a Kronecker product of common and individual precoding parameters to optimize data transmission and demodulation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If traditional linear precoding is used, then computational complexity is reduced, but inter-user interference cannot be effectively eliminated in strongly correlated channels
Solution Approach 1:
The patent segments the precoding process into two independent directions: first direction precoding (common precoding parameter) and second direction precoding (user-specific precoding parameter). This segmentation allows linear precoding to be applied in the first direction for low complexity, while non-linear precoding is applied in the second direction to eliminate inter-user interference, thus resolving the contradiction between computational complexity and interference elimination.
2Object-generated harmful factors
If traditional non-linear precoding is used, then inter-user interference is reduced, but computational complexity increases significantly
Solution Approach 1:
The patent divides the precoding operation into two stages with different complexity levels. The first direction uses linear precoding (low complexity) to handle common channel characteristics, while the second direction uses non-linear precoding (high complexity) only where necessary for user-specific interference cancellation. This segmented approach reduces overall computational complexity while maintaining interference reduction benefits.
Solution Approach 2:
The patent applies non-linear precoding partially - only in the second direction and only for specific users where needed, rather than applying it universally to all users and all directions. This partial application of non-linear precoding reduces the overall computational burden while still achieving effective inter-user interference reduction where necessary.
3Object-generated harmful factors
If traditional non-linear precoding is used, then inter-user interference is reduced, but reference signal overhead increases
Solution Approach 1:
The patent segments channel information acquisition into two parts: common channel information in the first direction (acquired through common reference signals) and user-specific channel information in the second direction (acquired through user-specific reference signals). This segmentation reduces the total reference signal overhead compared to traditional non-linear precoding that would require full channel state information for all users.
Solution Approach 2:
The patent uses common precoding parameters that can be reused across multiple users for the first direction precoding, reducing the need for extensive user-specific reference signals. The common precoding parameter acts as a template that is adapted for individual users, reducing overall reference signal requirements.
4Productivity
If FD-MIMO with large antenna scale is used, then spectral efficiency is improved, but channel correlation becomes strong making traditional precoding ineffective
Solution Approach 1:
The patent transforms the single-direction precoding problem into a two-dimensional problem by introducing direction separation. The first direction precoding handles the dominant channel correlation dimension, while the second direction precoding addresses the orthogonal dimension. This dimensional transformation allows the system to effectively manage strong channel correlation in FD-MIMO systems while maintaining high spectral efficiency.
Solution Approach 2:
The patent segments the channel correlation management into two directional components. By separating precoding into first direction (common) and second direction (user-specific), the system can independently optimize for channel correlation characteristics in each direction, making traditional precoding techniques effective even in strongly correlated FD-MIMO channels.
Data Source
AI summary
An electronic device operating on a base station side and includes a processing circuit configured to perform control to cause the electronic device to: estimate channel correlation in a first direction among a plurality of terminals communicating with the base station; and in response to that the estimated channel correlation in the first direction among the plurality of terminals satisfies a predetermined condition, transmit a first indication signal to indicate that a second measurement process is to be performed to determine channel information in a second direction after a first measurement process is to be performed to determine channel information in the first direction, and transmit, based on the channel information in the second direction, a second indication signal to indicate a precoding scheme for data to be transmitted from the base station to the plurality of terminals, the precoding scheme including linear precoding or non-linear precoding.