MIMO Signal Mapping With Precoding for Spatial Diversity Gain
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Solution Overview
Problem
Current MIMO communication systems face challenges in optimizing data transmission quality and diversity gain due to differences in modulation schemes and power levels between multiple antennas, leading to suboptimal data reception quality and spatial diversity.
Innovation Solution
The proposed method involves using a precoding matrix that adjusts the modulation schemes and power levels between two streams transmitted from different antennas, ensuring that the number of signal points in the I-Q plane aligns with the bit data transmission, and optimizing the minimum Euclidean distance between signal points to enhance spatial diversity and data reception quality.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If different modulation schemes are used for multiple antennas to adapt to varying channel conditions, then adaptability is improved, but manufacturing precision deteriorates due to misalignment between signal points and bit data transmission
Solution Approach 1:
The patent changes the parameter of signal point arrangement in the I-Q plane by using non-uniform spacing where inner signal points have smaller distances to adjacent points compared to outer signal points. This parameter change allows the modulation scheme to adapt to varying channel conditions while maintaining proper alignment between signal points and bit data transmission through the corrected mapping relationship.
2Productivity
If power levels between multiple antennas are adjusted to optimize transmission, then productivity is improved, but manufacturing precision deteriorates due to distorted signal point distribution
Solution Approach 1:
The patent applies parameter changes by modifying the power levels of transmitted signals from different antennas in a controlled manner. By adjusting the amplitude parameters of the modulated signals while using the corrected signal point mapping, the system can optimize transmission performance and data rate without causing distortion that would misalign signal points with their corresponding bit data.
Solution Approach 2:
The patent applies local quality by allowing different signal point spacing characteristics in different regions of the I-Q plane. Inner signal points have different spacing properties compared to outer signal points, enabling localized optimization of signal transmission while maintaining overall system precision through the corrected mapping relationship.
3Productivity
If signal point density is increased to improve data rate, then productivity is improved, but reliability deteriorates due to reduced minimum Euclidean distance
Solution Approach 1:
The patent applies local quality by implementing non-uniform signal point spacing where the minimum Euclidean distance varies by region. Inner signal points have smaller distances to enable higher data rate, while outer signal points maintain larger distances for reliability. The corrected mapping relationship ensures that each region's signal points are properly aligned with their corresponding bit data, resolving the contradiction between productivity and reliability.
Data Source
AI summary
In a transmission method according to one aspect of the present disclosure, a encoder performs error correction coding on an information bit string to generate a code word. A mapper modulates a first bit string in which the number of bits is the predetermined integral multiple of (X+Y) in the code word using a first scheme, the first scheme being a set of a modulation scheme in which an X-bit bit string is mapped to generate a first complex signal and a modulation scheme in which a Y-bit bit string is mapped to generate a second complex signal, and modulates a second bit string in which the first bit string is removed from the code word using a second scheme different from the first scheme.