MIMO Signal Generation with Dynamic Phase Precoding for LOS Reception
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Solution Overview
Problem
MIMO systems experience degradation in reception quality in Line-Of-Sight (LOS) environments, particularly in spatial multiplexing systems, where the Rician factor increases, leading to difficulties in broadcast or multicast communication.
Innovation Solution
A signal generation method and apparatus that apply weighting and phase changing processes to baseband signals using predetermined matrices and phase changing formulas, ensuring that the weighted signals satisfy specific transformation conditions, thereby improving reception quality in LOS environments.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If spatial multiplexing MIMO system is used to increase transmission speed, then data transmission rate is improved, but reception quality deteriorates as Rician factor increases in LOS environment
Solution Approach 1:
The patent applies dynamic switching between two signal generation processes (first process with weighting matrix F and second process with weighting matrix F') based on channel conditions. The reception quality improvement section describes switching between different precoding matrices adapted to the propagation environment, making the system dynamic rather than static to handle both NLOS and LOS conditions effectively
Solution Approach 2:
The patent changes the parameters of the weighting matrices (precoding matrices) based on the propagation environment. Specifically, it switches between different matrix configurations (F and F') depending on whether the environment is NLOS or LOS, thereby adapting the system parameters to maintain reception quality while preserving high transmission rates
2Reliability
If maximal ratio combination is used for single modulated signal transmission, then reception quality is improved in LOS environment, but transmission speed is limited
Solution Approach 1:
The patent merges the advantages of both maximal ratio combination (for reception quality) and spatial multiplexing (for transmission speed) by combining multiple modulated signals from multiple antennas with appropriate precoding. The reception quality improvement section describes how the combined approach achieves both high transmission rates and good reception quality by using multiple streams with adaptive precoding
3Adaptability or versatility
If conventional spatial multiplexing MIMO system is used for broadcast or multicast communication, then service coverage is expanded, but reception quality deteriorates in stabilized propagation environment
Solution Approach 1:
The patent implements dynamic adaptation for broadcast/multicast communication by switching between different signal generation processes based on propagation environment stability. The reception quality improvement section describes how the system adapts to different broadcast scenarios, maintaining quality in both unstable (NLOS) and stable (LOS) environments through appropriate matrix selection
Solution Approach 2:
The patent changes the precoding matrix parameters according to the propagation environment characteristics in broadcast/multicast scenarios. By switching between different matrix configurations, the system maintains service coverage while preventing reception quality deterioration in stabilized environments
Data Source
AI summary
A transmission method of simultaneously transmitting a first modulated signal and a second modulated signal at a common frequency performs precoding on both signals using a fixed precoding matrix and regularly changes the phase of at least one of the signals. One of signal generation processing in which phase change is performed and signal generation processing in which phase change is not performed is selectable, thereby improving general versatility in signal generation.