MIMO Signal Precoding With Phase Rotation for LOS Reception Quality
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Solution Overview
Problem
MIMO systems experience reception quality degradation in Line-Of-Sight (LOS) environments, particularly in broadcast or multicast communication, where the Rician factor increases, leading to high received electric field strength but impossible service reception due to quality degradation.
Innovation Solution
A signal generation method and apparatus that change the phase and apply weighting to baseband signals using different modulation schemes and real numbers, generating signals for transmission on a common frequency band and time, ensuring the weighted signals satisfy a specific relation, 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 dynamics by making the phase change量和phase change pattern variable rather than fixed. The phase changing quantity changes dynamically based on transmission conditions, and different phase change patterns can be selected adaptively. This dynamic adjustment allows the system to optimize performance for different propagation environments, resolving the contradiction between maintaining high transmission rates and ensuring reception quality in LOS conditions.
Solution Approach 2:
The patent changes key parameters including phase change quantity, phase change pattern, and modulation schemes. By varying these parameters adaptively, the system can optimize the balance between transmission efficiency and reception quality. Specifically, adjusting phase change quantities and patterns allows the system to counteract the degradation caused by high Rician factors while maintaining spatial multiplexing benefits.
2Reliability
If phase changing quantity is increased to improve reception quality, then reception quality is improved, but transmission efficiency decreases
Solution Approach 1:
The patent applies partial action by using phase changing only when necessary rather than continuously. The phase change quantity is adjusted partially based on channel conditions, and different phase change patterns are selected selectively. This partial application of phase changing improves reception quality only when needed, avoiding unnecessary overhead that would reduce transmission efficiency.
3Reliability
If different interleaving patterns are used for each transmit antenna to improve reception quality, then reception quality is improved, but device complexity increases
Solution Approach 1:
The patent applies universality by using a single interleaver structure that serves multiple functions. Rather than implementing separate interleavers for each antenna, the system uses one interleaver with adaptive phase changing capabilities that can handle multiple transmit antennas. This universal approach maintains reception quality improvement while reducing the complexity associated with multiple independent interleavers.
Data Source
AI summary
A transmission method for transmitting a first modulated signal and a second modulated signal in the same frequency at the same time. Each signal has been modulated according to a different modulation sheme. The transmission method applies precoding on both signals using a fixed precoding matrix, applies different power change to each signal, and regularly changes the phase of at least one of the signals, thereby improving received data signal quality for a reception device.