Precoding Matrix Computation for MU-MIMO Interference Reduction
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Solution Overview
Problem
In multi-user multiple-input multiple-output (MUMIMO) wireless communication systems, existing technologies face challenges in effectively reducing interference between different receiver devices, which affects the overall throughput and reliability of signal transmission.
Innovation Solution
The method involves computing a precoding matrix at the transmitter based on channel estimates from receiver devices, using either a nulling process for two receivers or a transmit zero forcing process for multiple receivers, to minimize interference by projecting signals onto null spaces or making them orthogonal across channels.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If precoding is applied to increase throughput in MUMIMO systems, then system productivity improves, but interference between receiver devices worsens
Solution Approach 1:
The patent applies preliminary anti-action by computing a precoding matrix that pre-compensates for interference before transmission. The precoding matrix is designed to nullify interference at specific receiver devices by projecting signal components onto null spaces of channel matrices, thereby preventing interference from occurring in the first place while maintaining high throughput
Solution Approach 2:
The patent converts harmful interference into a beneficial effect by using the interference information to design the precoding matrix. The interference channel characteristics are utilized to create null directions in the precoding matrix, transforming the harmful interference into a mechanism for spatial separation and interference cancellation, thereby improving overall system performance
2Reliability
If a precoding matrix is computed to reduce interference for one receiver, then reliability for that receiver improves, but computational complexity increases
Solution Approach 1:
The patent segments the interference reduction problem by applying different precoding strategies to different receiver devices. The precoding matrix is constructed by combining individual precoding components for each receiver, where each component is designed to address interference specific to that receiver. This segmentation allows the system to achieve reliable transmission for multiple receivers while managing computational complexity through modular processing
3Object-affected harmful factors
If nulling process is used for two receiver devices, then interference reduction is achieved, but device complexity increases compared to simpler methods
Solution Approach 1:
The patent applies parameter changes by dynamically adjusting the precoding matrix based on channel state information. The nulling process modifies the signal parameters (amplitude, phase, direction) to create nulls in the interference directions. By changing the precoding parameters according to real-time channel conditions, the system achieves interference reduction while adapting the complexity to the specific scenario
Data Source
AI summary
Systems and methods are provided for precoding a signal at a transmitter. A plurality of receiver devices is identified, and a first receiver device is selected from the plurality of receiver devices. The transmitter communicates with the first receiver device over a channel, and an estimate of the channel is determined. A precoding matrix is computed based on the estimate, such that when the transmitter transmits a signal that is precoded with the precoding matrix over the channel, interference from a second receiver device of the plurality of receiver devices over the channel is reduced.