HTD Precoding for LOS MIMO Throughput
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Solution Overview
Problem
In LOS MIMO wireless communication systems, achieving orthogonality of interfering signals is challenging due to impractical antenna spacing requirements, leading to high interference and limited data throughput in microwave backhaul systems.
Innovation Solution
The implementation of high threshold decomposition (HTD) precoding, which decomposes the channel matrix into unitary and orthogonal matrices M, A, and N, allowing for power distribution among streams to trade off increased data throughput and complexity of interference cancellation, thereby reducing interference and enhancing system performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If antenna spacing is increased to achieve orthogonality of interfering signals, then interference is reduced, but the system becomes impractical for microwave backhaul systems with long hops
Solution Approach 1:
The patent changes the parameter of antenna spacing from the impractical large values required for orthogonality to practical smaller values, and compensates by changing the precoding matrix parameters to achieve the same interference reduction effect
Solution Approach 2:
The patent introduces a precoding matrix as an intermediary component between the antenna elements and the transmitted signals. This precoding matrix processes the signals before transmission to create artificial orthogonality, substituting for the need for large physical antenna spacing
2Productivity
If conventional precoding methods like SVD are used, then interference cancellation is achieved, but data throughput is limited
Solution Approach 1:
The patent modifies the parameters of the precoding matrix decomposition, specifically using high threshold decomposition where the threshold is set higher than in conventional methods. This parameter change redistributes power more favorably among singular values, improving both throughput and interference cancellation
3Productivity
If power is concentrated in fewer streams to increase throughput, then data throughput increases, but interference cancellation complexity increases
Solution Approach 1:
The patent adjusts the threshold parameter in the decomposition to optimize the distribution of power among streams. By setting the threshold appropriately, it achieves a balance where sufficient power is allocated to maintain throughput while limiting the number of significant interference terms that require cancellation
Data Source
AI summary
Precoding is a technique that may be used in wireless communications when antenna spacing in a multiple-input multiple-output (MIMO) system is smaller than optimum spacing conditions. A precoding system and method are disclosed herein that distributes power among streams to trade-off increased data throughput and complexity of interference cancellation. Distributing power among streams may increase data throughput compared to singular value decomposition (SVD) precoding, but interference may be reduced compared to other methods that result in relatively high interference.