RoF Beamforming via Terminal Phase Control
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Solution Overview
Problem
Current wireless communication systems using Radio over Fibers (RoF) face challenges in beamforming for transmission/reception antennas without controlling the base station apparatus and without knowing the optical fiber distance, leading to degradation in wavelength utilization efficiency and increased costs.
Innovation Solution
The system employs a configuration with an accommodation station transmission unit that modulates light based on RF signals and outputs optical signals, which are demultiplexed by a base station optical demultiplexer to specific wavelengths, converted to electrical signals by photoelectric converters, and emitted by transmission antennas using a reflect array or transmit array for beam formation, without requiring base station control or fiber distance information.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If wavelength dispersion is used to control phase of RF signals for beamforming, then beamforming capability is improved, but wavelength utilization efficiency degrades and costs increase due to requiring base station control and fiber distance information
Solution Approach 1:
The patent extracts the beamforming control function from the base station to the terminal device. The terminal device independently controls the phase of RF signals for beamforming without requiring base station intervention or knowledge of fiber distance, thereby simplifying base station complexity while maintaining beamforming capability
Solution Approach 2:
The terminal device performs self-service by autonomously adjusting the phase of RF signals based on wavelength dispersion characteristics. This eliminates the need for base station control and fiber distance information, resolving the technical contradiction between beamforming capability and control complexity
2Measurement precision
If base station controls phase adjustment for beamforming, then beamforming precision is improved, but system complexity and costs increase
Solution Approach 1:
The patent inverts the traditional control architecture by shifting beamforming control from the base station to the terminal device. This inversion maintains beamforming precision through accurate phase control while reducing system complexity by eliminating centralized control requirements
3Manufacturing precision
If fiber distance information is required for wavelength adjustment, then transmission accuracy is improved, but ease of operation deteriorates
Solution Approach 1:
The terminal device autonomously handles wavelength adjustment and phase control without requiring external fiber distance information. This self-service approach maintains transmission accuracy while significantly improving ease of operation by eliminating the need for manual configuration or knowledge of fiber characteristics
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 enables effective beamforming for transmission/reception antennas while maintaining high wavelength utilization efficiency and reducing costs by eliminating the need for base station control and fiber distance information.
Implementation Method 1
an optical demultiplexer including a plurality of output ports assigned to wavelengths of the light, the optical demultiplexer being configured to obtain, from an input port, the optical signal output by the accommodation station transmission unit, demultiplex the obtained optical signal for each wavelength, and output the demultiplexed optical signal from the output port corresponding to the wavelength
Implementation Method 2
a plurality of photoelectric converters connected to the plurality of output ports of the optical demultiplexer, the plurality of photoelectric converters being configured to convert the optical signal output by the optical demultiplexer into electrical signals to demodulate the RF signal
Implementation Method 3
a transmission beam formation unit including a reflect array or a transmit array, the reflect array or the transmit array being configured to receive a plurality of RF signal emitted by each of the plurality of transmission antennas and form, for each of the plurality of received RF signals, a plurality of transmission beams in different directions depending on positions of the plurality of transmission antennas that are a transmission source of the RF signal
Data Source
AI summary
An accommodation station transmission unit modulates light to generate an optical signal based on an RF signal and outputs the generated optical signal, a base station transmission unit obtains the optical signal from an input port, demultiplexes the obtained optical signal for each wavelength, outputs the demultiplexed optical signals from output ports of corresponding wavelengths from among a plurality of output ports allocated to each of the wavelengths of the light, and demodulates the RF signal by converting the optical signals output by the output ports into electrical signals, a plurality of transmission antennas emit the demodulated RF signal, and a reflect array or a transmit array receives the RF signal emitted by each of the transmission antennas and forms a transmission beam in a different direction for each position of the transmission antenna that is a transmission source of the RF signal for each RF signal.