Precoding Weight Matrix Hopping for MIMO Reception Quality
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Solution Overview
Problem
In multi-antenna communication systems, particularly in spatial multiplexing MIMO systems, reception quality deteriorates in Line of Sight (LOS) environments due to increased Rician factors, leading to service unavailability in broadcast or multicast communications despite high electric field strength.
Innovation Solution
A precoding method that generates precoded signals by selecting and regularly hopping between a set 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 productivity is improved, but reception quality deteriorates in LOS environments with high Rician factors
Solution Approach 1:
The system dynamically switches between different precoding methods (spatial multiplexing MIMO and single modulation signal transmission) based on the Rician factor detected in the propagation environment. This dynamic adaptation allows the system to maintain high transmission speed in NLOS environments while ensuring reliable reception in LOS environments by transitioning to a more robust transmission mode when direct waves dominate.
Solution Approach 2:
The system changes the transmission parameter (precoding method) based on the propagation environment characteristics, specifically the Rician factor. By detecting whether the environment is LOS or NLOS and adjusting the precoding method accordingly, the system resolves the contradiction between achieving high transmission speed and maintaining reception quality.
2Reliability
If maximal ratio combining is used for single modulated signal transmission, then reception quality is improved in LOS environments, but transmission speed is limited compared to spatial multiplexing MIMO
Solution Approach 1:
The system dynamically selects between single modulation signal transmission with maximal ratio combining and spatial multiplexing MIMO based on the propagation environment. In LOS environments, it uses maximal ratio combining to ensure high reception quality, while in NLOS environments, it switches to spatial multiplexing MIMO to maximize transmission speed, thus resolving the speed-quality tradeoff.
Solution Approach 2:
The transmission parameter (number of transmission streams and precoding method) is changed based on the detected Rician factor. When the Rician factor indicates LOS conditions, the system switches to a parameter configuration optimized for reception quality; when it indicates NLOS conditions, it switches to parameters optimized for transmission speed.
3Adaptability or versatility
If conventional spatial multiplexing MIMO is used in broadcast or multicast communication, then service coverage is expanded, but service availability deteriorates in LOS environments due to reception quality degradation
Solution Approach 1:
The broadcast or multicast communication system dynamically adjusts the precoding method based on the propagation environment detected by the transmitting device. This allows the system to maintain service availability in LOS environments by switching to appropriate precoding methods while still providing wide service coverage through multi-antenna transmission in NLOS environments.
Solution Approach 2:
The transmitting device detects the propagation environment (Rician factor) and uses this feedback information to select the appropriate precoding method for broadcast or multicast communication. This feedback mechanism ensures that the system adapts to LOS conditions to maintain service availability while preserving the ability to provide wide coverage in NLOS conditions.
Data Source
AI summary
Disclosed is a precoding method for generating, from a plurality of baseband signals, a plurality of precoded signals that are transmitted in the same frequency bandwidth at the same time. According to the precoding method, one matrix is selected from among matrices defining a precoding process that is performed on the plurality of baseband signals by hopping between the matrices. A first baseband signal and a second baseband signal relating to a first coded block and a second coded block generated by using a predetermined error correction block coding scheme satisfy a given condition.