Base Station Interference Cancellation in Multi-User MIMO Systems
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Solution Overview
Problem
Conventional multiuser MIMO transmission using dirty paper coding (DPC) fails to sufficiently suppress interference due to channel status mismatches between the transmitter and receiver, leading to degraded reception quality.
Innovation Solution
A wireless communication system that includes a base station and terminal devices capable of spatial multiplexing, where the terminal devices calculate and transmit interference cancellation coefficients to the base station, allowing the base station to generate control signals for interference cancellation, thereby enabling effective suppression of interference components during data transmission.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If dirty paper coding (DPC) is used for multiuser MIMO transmission, then data transmission rate can be increased, but interference suppression becomes insufficient due to channel status mismatches between transmitter and receiver
Solution Approach 1:
The patent implements feedback mechanisms where terminal devices measure channel status and transmit channel status information back to the base station. This feedback loop allows the transmitter to update its channel knowledge and adjust precoding matrices accordingly, reducing the mismatch between transmitter and receiver channel status understanding, thereby maintaining both high data transmission rates and effective interference suppression
Solution Approach 2:
The patent performs preliminary channel status estimation and precoding matrix selection at the terminal device before actual data transmission. By pre-calculating and preparing the appropriate precoding matrices based on estimated channel conditions, the system can quickly adapt to channel variations and maintain optimal performance without waiting for extensive feedback during data transmission
2Productivity
If spatial multiplexing is used to transmit different data series over the same physical channel, then communication capacity is improved, but interference from other users increases
Solution Approach 1:
The patent applies different precoding matrices to different terminal devices based on their specific channel conditions and spatial locations. Each user receives a customized precoding matrix that optimizes signal quality for that particular user's spatial position, thereby enabling spatial multiplexing while minimizing interference between users through localized signal optimization
Solution Approach 2:
The patent converts the harmful interference from spatially multiplexed users into useful information by having terminal devices measure and report channel status information. This interference measurement is then used to calculate appropriate precoding matrices that actively cancel or mitigate the interference, transforming the originally harmful effect into a basis for interference suppression
Data Source
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AI summary
A base station device (10) communicates between a first terminal device and a second terminal device over the same channel by spatial multiplexing. The base station device (10) comprises an interference cancellation coefficient extractor (30) that extracts an interference cancellation coefficient from a signal received from the first terminal device to cancel interference on a propagation channel with the first terminal device in advance, and transmits a pilot signal that contains information related to the interference cancellation coefficient to the second terminal device. In addition, the base station device (10) also comprises an interference canceller (16) that uses the interference cancellation coefficient to cancel an interference component from transmission data to be transmitted over the same channel, and transmits the transmission data from which the interference component has been canceled by the interference canceller (16) to the first terminal device and the second terminal device over the same channel. A wireless communication system is provided which, in a multi-user MIMO, suppresses superimposed interference components resulting from channel fluctuations and channel estimation errors when interference cancellation is performed in advance in a base station unit on a modulated signal to be transmitted.