OFDM MIMO Transmission with Adaptive Phase Switching for LOS Reception
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Solution Overview
Problem
Conventional MIMO systems experience reception quality degradation in Line-Of-Sight (LOS) environments, particularly in broadcast or multicast communication, where high received electric field strength does not guarantee service reception due to the unique challenges posed by spatial multiplexing.
Innovation Solution
A MIMO system employing phase changing methods and interleaving patterns for transmission devices, combined with iterative decoding techniques, to improve reception quality in LOS environments.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If spatial multiplexing MIMO is used to increase transmission speed, then data transmission rate is improved, but reception quality deteriorates in LOS environments
Solution Approach 1:
The system dynamically switches between spatial multiplexing MIMO mode and phase changing MIMO mode based on reception quality feedback. When reception quality falls below a threshold in LOS environments, the system transitions to phase changing MIMO which applies time-varying phase rotations to improve signal reliability while maintaining acceptable transmission rates.
Solution Approach 2:
The invention changes the transmission mode parameter from fixed spatial multiplexing to adaptive mode selection. By modifying the transmission parameters (switching between different MIMO modes) based on environmental conditions and reception quality, the system resolves the contradiction between high data rate and reliable reception in LOS environments.
2Device complexity
If conventional MIMO transmission is used in LOS environments, then transmission simplicity is maintained, but reception quality deteriorates despite high received electric field strength
Solution Approach 1:
The system maintains simplicity by using a unified MIMO framework that adapts its behavior dynamically. Rather than implementing completely separate transmission systems, the invention uses adaptive mode switching within the MIMO architecture, keeping the overall system simple while improving reception quality through phase changing operations when needed.
Solution Approach 2:
The transmission system automatically adjusts its mode based on reception quality feedback without requiring complex external intervention. The base station monitors reception quality and self-adjusts by switching between spatial multiplexing and phase changing MIMO modes, maintaining transmission simplicity while ensuring reliable reception.
Data Source
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AI summary
The present invention provides a transmission and reception scheme for transmitting OFDM symbols, wherein a transmission signal of a frame includes multiple subframes containing OFDM symbol and the subframe includes a subframe boundary symbol and a data symbol, the subframe boundary symbol is the leading OFDM symbol of the subframe and/or the trailing OFDM symbol of the subframe, and the number of the pilots in the subframe boundary symbol is more than that in the data symbol.