Iterative Precoding Matrix for Multi-User Interference Mitigation
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Solution Overview
Problem
Existing multi-user interference systems face challenges in maximizing system capacity and practical implementation of interference alignment due to low system capacity and difficulty in constructing interference alignment on actual channels, especially when data is transmitted in TDMA mode.
Innovation Solution
A precoding method and apparatus that iteratively calculates a precoding matrix using a Lagrange function, transmit power, receive filter matrix, and weighting matrix to converge to a threshold, effectively mitigating interference between users and improving the sum rate by optimizing the weighted sum rate and minimizing weighted mean square error.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If TDMA mode is used to prevent interference between users, then interference is eliminated, but system capacity becomes low
Solution Approach 1:
The patent transforms the interference management approach by changing the parameter space from time-domain separation (TDMA) to spatial-domain precoding. By introducing precoding matrices that operate in the spatial domain, the system can maintain simultaneous transmissions while controlling interference through parameter optimization, thereby resolving the contradiction between interference elimination and capacity maintenance.
Solution Approach 2:
The patent moves the interference management from the time dimension (TDMA) to the spatial dimension through precoding. By utilizing multiple antennas and spatial processing, the system can separate users in space rather than time, allowing simultaneous transmissions without interference, thus resolving the capacity limitation imposed by time-division approaches.
2Productivity
If interference alignment is implemented on special channels, then capacity is improved, but practical construction on actual channels is difficult
Solution Approach 1:
The patent generalizes interference alignment from special channel conditions to actual channels by changing the parameter space. Instead of relying on specific channel structures (like identity matrices), the patent uses general precoding matrices with optimized parameters that work for arbitrary channel conditions, making the solution practically implementable while maintaining capacity improvements.
Solution Approach 2:
The patent introduces dynamic precoding matrices that adapt to actual channel conditions rather than relying on fixed special channel structures. By making the precoding parameters dynamic and adjustable based on channel state information, the system can achieve interference alignment on practical channels, resolving the implementation difficulty while maintaining capacity benefits.
3Object-affected harmful factors
If complete channel information is shared among users for joint transmission, then interference can be managed, but information transfer and sharing overhead increases
Solution Approach 1:
The patent segments the channel information requirements by introducing separate precoding matrices for different users and channels. Instead of requiring complete channel information sharing, each user only needs their own precoding matrix and relevant channel state information, dividing the information requirements into manageable segments that reduce overhead while still enabling effective interference management.
Solution Approach 2:
The patent performs preliminary precoding operations at the transmitter side before transmission, embedding interference management information directly in the transmitted signals. This preliminary action eliminates the need for extensive real-time information sharing among users, as the interference coordination is pre-computed and embedded in the precoding matrices, thereby reducing information overhead.
Data Source
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AI summary
A precoding method and apparatus are disclosed. The corresponding method includes: constructing a Lagrange function according to a precoding matrix, transmit power, a receive filter matrix and a weighting matrix, and obtaining a Lagrange multiplier by using the Lagrange function; updating the precoding matrix according to the Lagrange multiplier to obtain an iterative precoding matrix and an iterative receive filter matrix; obtaining an iterative Lagrange multiplier according to the iterative precoding matrix, the transmit power, the iterative receive filter matrix and the weighting matrix, and repeating the above steps in an iterative manner of updating the iterative precoding matrix according to the iterative Lagrange multiplier till the iterative precoding matrix converges to a threshold; and precoding information to be transmitted according to the iterative precoding matrix converging to the threshold. The present invention has the features of improving performance of a multi-user interference system, mitigating interference between users, and reducing information transfer and sharing required for user cooperative communication, and is capable of effectively mitigating interference between users and improving the sum rate of the system.