Antenna Pre-coder for Mutual Coupling Distortion Mitigation
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Solution Overview
Problem
Large antenna array wireless systems face complexity in mitigating mutual coupling-based non-linear distortion effects due to electromagnetic interactions between antenna elements, making existing digital pre-distortion methods impractical.
Innovation Solution
An antenna arrangement with a pre-coder that suppresses correlation between transmit signal components, allowing for reduced complexity in distortion mitigation by mapping data streams to antenna elements to minimize mutual coupling effects, thereby eliminating the need for complex digital pre-distortion methods.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If digital pre-distortion methods are used to mitigate non-linear distortion in large antenna arrays, then distortion compensation is achieved, but system complexity increases prohibitively due to electromagnetic mutual coupling effects between antenna elements
Solution Approach 1:
The patent divides the antenna array into multiple sub-arrays with spaced-apart antenna elements. By segmenting the array, the mutual coupling between elements is reduced, allowing simpler distortion compensation methods to be applied to each sub-array independently rather than requiring complex compensation for the entire array.
Solution Approach 2:
The patent introduces a precoder as an intermediary component that processes transmit signals before they reach the antenna elements. The precoder suppresses correlation between signals from adjacent antenna elements, which mitigates mutual coupling effects and enables simpler distortion compensation approaches.
2Productivity
If antenna elements are placed adjacently to form a compact array, then array capacity increases, but mutual coupling-based non-linear distortion effects increase
Solution Approach 1:
The antenna array is segmented into multiple sub-arrays where elements within each sub-array are spaced apart to reduce mutual coupling. This segmentation allows the system to maintain high capacity through multiple sub-arrays while avoiding the harmful mutual coupling effects that would occur in a densely packed single array.
Solution Approach 2:
Different spatial regions of the antenna array are assigned different element spacing characteristics. Elements within the same sub-array maintain larger spacing to reduce mutual coupling, while the overall array structure preserves capacity through the coordinated operation of multiple sub-arrays.
3Reliability
If complex digital pre-distortion algorithms are deployed to compensate for PA distortion, then signal quality improves, but production and operating costs increase due to extensive processing power and memory resources required
Solution Approach 1:
The patent extracts and addresses the root cause of mutual coupling-based distortion by modifying the antenna array structure and signal correlation properties. By taking out the mutual coupling problem through spatial segmentation and precoding, simpler and less costly distortion compensation algorithms can be used compared to complex algorithms required for unmodified arrays.
Solution Approach 2:
The precoder performs preliminary action by suppressing correlation between transmit signals before the signals reach the power amplifiers and antenna elements. This preliminary suppression of correlation prevents the generation of complex mutual coupling-based distortion, allowing simpler compensation methods to be used later and reducing overall system costs.
Data Source
AI summary
The present disclosure relates to an antenna arrangement and a method for radio transmission. The antenna arrangement comprises a pre-coder (310) connected to an antenna array (320). The antenna array (320) comprises a number N of antenna elements ai (321), i=1, 2, . . . , N, each antenna element ai being configured to receive a respective transmit signal component TXi from the pre-coder (310). The pre-coder (310) is configured to receive a number M<N of independent data streams sj, j=1, 2, . . . , M, and to generate the N transmit signal components, wherein the generating comprises suppressing a correlation between any two transmit signal components TXi1 and TXi2 received by antenna elements ai1 and ai2 arranged adjacently in the antenna array (320).