Transmission Device Phase Rotation for LOS Reception Quality
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Solution Overview
Problem
Existing transmission methods do not effectively improve single stream and multi-stream data reception quality in line of sight (LOS) propagation environments, particularly when transmitting a combination of single stream and multi-stream signals using a multi-carrier transmission scheme like OFDM.
Innovation Solution
A transmission device that generates precoded signals using a weighting synthesizer and applies phase changes to these signals, along with pilot signal insertion, to enhance data reception quality. The phase changes are applied based on a communications scheme, with Δλ satisfying specific radians conditions, and the signals are modulated using quadrature amplitude modulation (QAM) with non-uniform mapping.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional MIMO transmission methods are used in LOS environments, then multi-stream signal transmission is achieved, but single stream data reception quality deteriorates
Solution Approach 1:
The patent applies dynamic phase changes to the second precoded signal using the formula exp(j×i×Δλ), where the phase rotation varies with symbol index i. This dynamic adjustment adapts the transmission characteristics to LOS propagation conditions, improving single stream reception quality while maintaining multi-stream capability through selective application of phase changes.
Solution Approach 2:
The patent modifies transmission parameters by applying controlled phase rotations to precoded signals. The phase change parameter Δλ is specifically designed to mitigate signal density issues in LOS environments, transforming the signal characteristics to improve reception quality without compromising the underlying MIMO transmission structure.
2Reliability
If phase changes are applied to precoded signals, then data reception quality improves, but signal processing complexity increases
Solution Approach 1:
The patent segments the phase change application by selectively applying it only to the second precoded signal while leaving the first precoded signal unchanged. This segmented approach improves reception quality for specific signal components without requiring complex processing across all signals, thereby limiting the increase in overall system complexity.
Solution Approach 2:
The patent applies local quality enhancement by implementing phase changes only where needed (in the second precoded signal path) rather than uniformly across all transmission paths. This localized application targets specific reception quality issues in LOS environments while avoiding unnecessary processing complexity in other parts of the system.
Data Source
AI summary
A transmission device that improves data reception quality includes: a weighting synthesizer that generates a first precoded signal and a second precoded signal from a first baseband signal and a second baseband signal, respectively; a phase changer that applies a phase change of i×Δλ to the second precoded signal; an inserter that inserts a pilot signal into the second precoded signal applied with the phase change; and a phase changer that applies a phase change to the second precoded signal applied with the phase change and inserted with the pilot signal. Δλ satisfies π/2 radians<Δλ<π radians or π radians<Δλ<3π/2 radians. Each of the first baseband signal and the second baseband signal is modulated via a modulation scheme of quadrature amplitude modulation (QAM) using non-uniform mapping.