OAM Signal Phase Modulation for Bore-Sight Transmission
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Solution Overview
Problem
Current radio communication systems using Orbital Angular Momentum (OAM) modes face inefficiencies due to phase singularity issues at the bore-sight direction, particularly in satellite communications, requiring large antennas and precise pointing, making them impractical for long-distance transmissions.
Innovation Solution
The implementation of a multidimensional space modulation technique that allows orthogonal RF OAM modes to be transmitted and received in the bore-sight direction using a single standard antenna, overcoming phase singularity by introducing supplementary phase modulation and reducing the need for phased arrays.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If OAM modes are used to increase transmission capacity, then transmission capacity is improved, but phase singularity issues occur at the bore-sight direction requiring large antennas and precise pointing
Solution Approach 1:
The patent changes the fundamental parameter of OAM mode transmission by introducing supplementary phase modulation to the carrier signal. This modifies the phase characteristics of the transmitted signal, allowing the signal to maintain orthogonality and transmit information without suffering from phase singularity issues at the bore-sight direction, thereby resolving the contradiction between transmission capacity and antenna system complexity
Solution Approach 2:
The patent introduces a supplementary phase modulation as an intermediary mechanism between the OAM modes and the carrier signal. This intermediary phase modulation compensates for the phase singularity problem, enabling standard antennas to transmit and receive OAM modes effectively without requiring complex phased arrays or precise pointing mechanisms
2Productivity
If phased arrays are used to transmit and receive OAM modes, then transmission capacity is improved, but device complexity and antenna size increase
Solution Approach 1:
The patent extracts and removes the requirement for phased arrays from the OAM transmission system. By introducing supplementary phase modulation, the system can achieve OAM mode transmission using standard single-element antennas, completely eliminating the need for complex phased array structures and their associated weight and complexity
Solution Approach 2:
The patent replaces expensive and complex phased array antenna systems with simple, standard, off-the-shelf antennas. This substitution dramatically reduces system cost, weight, and complexity while maintaining the ability to transmit and receive OAM modes effectively through supplementary phase modulation
3Productivity
If precise pointing is required for OAM transmission, then transmission capacity is improved, but ease of operation deteriorates
Solution Approach 1:
The supplementary phase modulation mechanism provides self-correction for phase singularity issues, allowing the system to maintain effective transmission without requiring external adjustment of pointing accuracy. The phase modulation automatically compensates for deviations, making the system self-sufficient and eliminating the need for precise manual pointing alignment
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This approach increases transmission capacity and efficiency, simplifies antenna design, and enables the use of existing antennas for satellite communications by eliminating the need for phased arrays and reducing antenna size, while maintaining signal orthogonality and bandwidth efficiency.
Implementation Method 1
introducing supplementary phase modulation
Implementation Method 2
Orbital Angular Momentum (OAM) modes
Implementation Method 3
twisted signals in frequency domain
Data Source
Figure 1~2
Figure 3~4
Figure 5~6
AI summary
Disclosed herein is a radio communications method that comprises generating, by a transmitter (7), a digital time signal, that is time-limited, carries a limited sequence of digital symbols to be transmitted and results from an approximation of the Hilbert transform in frequency domain; wherein said approximation is based on a frequency main mode, that is associated with an orbital angular momentum mode with topological charge equal to zero, and that includes main mode frequency samples carrying respective digital symbols of said limited sequence via said orbital angular momentum mode with topological charge equal to zero; said approximation being based also on one or more frequency twisted modes carrying the other digital symbols of said limited sequence; wherein each frequency twisted mode is associated with a corresponding orbital angular momentum mode with a respective topological charge different than zero, and includes respective twisted mode frequency samples carrying one or more respective digital symbols of said limited sequence via said corresponding orbital angular momentum mode with said respective topological charge different than zero. The method further comprises transmitting, by the transmitter (7), a radio frequency signal carrying the digital time signal generated. Moreover, the method comprises also carrying out, by a receiver (8), the following steps: receiving the radio frequency signal transmitted by the transmitter (7); processing the received radio frequency signal so as to obtain a corresponding incoming digital signal; and extracting, from the incoming digital signal, the digital symbols carried by said incoming digital signal.