Multi-User MIMO Channel Matrix Decomposition for Interference Elimination
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Solution Overview
Problem
In multi-user MIMO communication systems, interference among multiple users affects system performance, and existing Tomlinson-Harashima pre-coding techniques do not guarantee optimality due to lack of cooperative processing among receiving antennas.
Innovation Solution
The method involves decomposing the channel matrix into a product of a block triangular matrix and a unitary matrix, performing Tomlinson-Harashima pre-coding, and using forward filtering with the unitary matrix to generate and transmit signals, while receiving ends pre-filter using a unitary matrix and diagonal matrix to recover raw data, effectively eliminating interference and improving system capacity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If Tomlinson-Harashima pre-coding is applied in multi-user MIMO system treating receiving antennas as separate users, then implementation simplicity is improved, but system optimality deteriorates due to lack of cooperative processing among receiving antennas
Solution Approach 1:
The patent segments the receiving antennas into virtual users, allowing each antenna to be processed independently through THP while maintaining the overall MIMO structure. This segmentation enables the simple THP implementation to work within the more complex MIMO framework, resolving the contradiction between simplicity and optimality.
Solution Approach 2:
The patent introduces channel matrix decomposition as an intermediary step between the simple THP pre-coding and the MIMO channel. By decomposing the channel matrix into triangular and unitary components, the system enables cooperative processing among receiving antennas while maintaining the simplicity of THP implementation, thus resolving the optimality-simplicity contradiction.
2Productivity
If multiple users transmit simultaneously at the same frequency, then system communication capacity is improved, but interference among users increases
Solution Approach 1:
The patent applies Tomlinson-Harashima pre-coding as a preliminary action at the transmitter side to pre-eliminate inter-user interference before signal transmission. By calculating and subtracting the interference components in advance, the system enables multiple users to transmit simultaneously at the same frequency without harmful interference, thus resolving the capacity-interference contradiction.
Solution Approach 2:
The patent transforms the channel matrix into a triangular form through decomposition, changing the parameter structure of the channel. This parameter transformation enables the system to handle multiple simultaneous transmissions by converting the interference problem into a structured form that can be easily managed through the triangular decomposition, resolving the capacity-interference trade-off.
Data Source
AI summary
A multi-user multi-input multi-output (MIMO) method for transmitting signal with a includes: performing a Tomlinson-Harashima pre-coding (THP) on raw data; decomposing a channel matrix to a product of a block triangular matrix and a unitary matrix, and generating a signal to be transmitted by performing a forward filtering on the THP coded data by using the unitary matrix. A multi-user MIMO apparatus for transmitting signal includes an interference pre-eliminating unit, a modulo unit, a forward filtering unit, and a channel matrix decomposing unit. A multi-user MIMO communication system is further provided.