MIMO Transmission Device Phase Changing for LOS Reception
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Solution Overview
Problem
Conventional MIMO systems face reception quality degradation in Line-Of-Sight (LOS) environments, particularly in broadcast or multicast communications, where the high electric field strength can lead to service reception failure due to signal interference.
Innovation Solution
A transmission method and device that implement spatial multiplexing MIMO with a precoding matrix and phase changing techniques to improve reception quality in LOS environments, allowing a reception device with a limited number of antennas to effectively decode signals by regularly changing the phase of transmitted signals over time.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If spatial multiplexing MIMO is implemented in LOS environments, then data transmission capacity is improved, but reception quality deteriorates due to signal interference from high electric field strength
Solution Approach 1:
The patent applies periodic phase changing to transmitted signals using a phase changing vector that varies periodically over time. This periodic action transforms the static interference problem in LOS environments into a dynamic situation where the receiver can exploit the known phase evolution pattern to separate and decode signals, thereby maintaining high reception quality while preserving the high data transmission capacity of spatial multiplexing MIMO
Solution Approach 2:
The patent changes the phase parameter of transmitted signals by applying a phase changing vector that modifies the phase of each transmitted signal over time. This parameter change allows the receiver to distinguish between different transmitted signals even in LOS conditions, converting a harmful static interference scenario into a solvable dynamic signal separation problem
2Reliability
If cross-polarized antennas are used for MIMO transmission, then signal diversity is improved, but compatibility with legacy SISO receivers is lost
Solution Approach 1:
The patent designs the transmission system to be universal by ensuring that signals transmitted using cross-polarized antennas with phase changing can be received by both advanced MIMO receivers and legacy SISO receivers. The phase changing mechanism provides diversity benefits for MIMO receivers while the overall signal structure remains compatible with SISO receivers, allowing the same transmission infrastructure to serve multiple receiver types
3Productivity
If multiple antennas are added to the transmission device, then data rate is improved, but system complexity increases
Solution Approach 1:
The patent uses periodic phase changing as a relatively simple mechanism to enable effective signal separation at the receiver side. This approach achieves high data rates with multiple antennas without requiring complex signal processing at the transmitter, as the structured phase evolution can be compensated for using the known phase changing vector at the receiver, thereby limiting the increase in system complexity
Data Source
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AI summary
A transmission device transmits by performing SISO using a first polarization and by performing MISO and MIMO using the first (V) polarization and a second (H) polarization. For SISO communication, transmission is performed using an antenna having the first (V) polarization. For MISO and MIMO communication, transmission is performed using the antenna having the first (V) polarization and an antenna having the second (H) polarization. Accordingly, a reception device equipped only with a system for the antenna having the first (V) polarization is able to continue receiving the transmit data by SISO.