Dynamic Precoding Weight Matrices for MIMO Reception Quality
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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 poor service reception in broadcast or multicast communication.
Innovation Solution
A precoding method that generates precoded signals by selecting and regularly hopping between a plurality of predetermined precoding weight matrices, expressed using positive real numbers, to improve 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 transmission capacity is improved, but reception quality deteriorates in LOS environments with high Rician factor
Solution Approach 1:
The patent applies dynamic precoding by switching between multiple codebooks (first and second codebooks) based on the Rician factor detected in the propagation environment. The precoding weight matrix is not fixed but dynamically adjusted according to channel conditions, allowing the system to adapt to LOS environments while maintaining spatial multiplexing benefits
Solution Approach 2:
The patent changes the precoding parameters by selecting different codebooks and precoding weight matrices depending on the Rician factor threshold. When Rician factor exceeds the threshold (indicating LOS environment), the system switches to a second codebook with different precoding weights, thereby changing the transmission parameters to suit the specific propagation conditions
2Reliability
If maximal ratio combining is used in LOS environment, then reception quality is improved for single modulated signal, but reception quality deteriorates in spatial multiplexing MIMO system
Solution Approach 1:
The patent creates a universal precoding system that can handle both single signal transmission and spatial multiplexing MIMO transmission. By providing multiple codebooks that can be selected based on transmission mode and Rician factor, the system achieves multi-functionality, accommodating different transmission scenarios without requiring separate optimized systems for each mode
Data Source
AI summary
Disclosed is a relay method including: receiving, as input, respective reception signals by two receive antennas, the reception signals each including a reception signal resulting from multiplexing respective transmission signals transmitted by two transmission antennas in a first frequency band; performing frequency conversion on the reception signal received by one of the receive antennas so as to obtain a signal of a third frequency band; and performing frequency multiplexing on the signal having the third frequency band and the reception signal received by the other of the receive antennas.