Time Reversal Precoding for OFDM/OQAM MIMO Interference
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Solution Overview
Problem
Current wireless communication systems using OFDM/OQAM modulation do not effectively exploit spatial diversity in MIMO systems, leading to inefficiencies and increased complexity in interference elimination, especially with multiple receiving antennas.
Innovation Solution
A method involving specific coding and Time Reversal precoding techniques for OFDM/OQAM modulation in MIMO systems, where data is encoded and transmitted using multiple antennas, and decoded with circulant channel matrices to avoid symbol interference, allowing for efficient spectral use and low-complexity processing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If OFDM/OQAM modulation is used in MIMO systems, then spectral efficiency is improved, but interference elimination complexity increases
Solution Approach 1:
The patent applies preliminary action by performing Time Reversal precoding at the transmitter before signal transmission. The channel impulse response is estimated and time-reversed to pre-compensate for channel effects, focusing signal energy at the receiver and eliminating interference without requiring complex post-processing at the receiver end.
Solution Approach 2:
The patent introduces an intermediary processing step using circulant channel matrices and specific coding schemes that transform the complex MIMO interference elimination problem into a simpler form. The circulant structure of the channel matrix serves as an intermediary that enables efficient decomposition and processing of the received signal.
2Reliability
If spatial diversity is exploited in MIMO systems, then transmission quality is improved, but processing complexity increases
Solution Approach 1:
The transmitter performs Time Reversal precoding in advance, pre-compensating for channel effects and focusing signal energy before transmission. This preliminary action exploits spatial diversity while simplifying receiver processing, as the receiver only needs to perform standard OFDM/OQAM demodulation without complex MIMO detection.
Solution Approach 2:
The patent changes the parameter representation by using circulant channel matrices and specific coding schemes that transform the complex MIMO processing into operations on structured matrices. This parameter transformation enables efficient exploitation of spatial diversity with reduced computational complexity through the inherent structure of the channel representation.
3Object-generated harmful factors
If Time Reversal precoding is applied, then interference is reduced, but transmitter processing complexity increases
Solution Approach 1:
The patent changes the parameter representation by using circulant channel matrices and specific coding schemes that transform the complex MIMO processing into operations on structured matrices. This parameter transformation enables efficient Time Reversal precoding at the transmitter with reduced computational complexity through the inherent structure of the channel representation.
4Reliability
If multiple antennas are used, then spatial diversity is improved, but system complexity increases
Solution Approach 1:
The transmitter performs Time Reversal precoding in advance, pre-compensating for channel effects and focusing signal energy before transmission. This preliminary action exploits spatial diversity while simplifying receiver processing, as the receiver only needs to perform standard OFDM/OQAM demodulation without complex MIMO detection.
Solution Approach 2:
The patent changes the parameter representation by using circulant channel matrices and specific coding schemes that transform the complex MIMO processing into operations on structured matrices. This parameter transformation enables efficient exploitation of spatial diversity with reduced computational complexity through the inherent structure of the channel representation.
Data Source
Figure 1a~1b
Figure 1c~2
Figure 3a~3b
AI summary
The present invention relates to a method of transmitting data between a transmitter furnished with M≥ 1 transmission antenna(s) and a receiver furnished with N≥ 2 reception antennas, in which said data are coded by means of an OFDM/OQAM modulation comprising L≥ 1 subcarriers. The invention combines a specific coding/decoding with a precoding by Time Reversal. Application to high speed radio communications.