M-UCA OAM Multiplexing System Signal Processing Segmentation
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Solution Overview
Problem
In OAM multiplexing transmission techniques, the digital signal processing amount increases significantly with the number of multiplexed signals, leading to reduced reception power and transmission capacity, especially at higher-order OAM modes and increased transmission distances, limiting the number of multiplexed streams due to restricted signal processing capabilities.
Innovation Solution
The implementation of a multi-UCA (M-UCA) system with concentrically disposed UCAs at both the transmitting and receiving stations, where each UCA generates and transmits signals in multiple OAM modes, allowing for spatial multiplex transmission and demultiplexing, with signal processing units that manage streams across multiple UCAs to minimize processing requirements and maintain transmission capacity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the number of multiplexed OAM modes is increased to improve transmission capacity, then the transmission capacity is improved, but the digital signal processing amount increases significantly
Solution Approach 1:
The patent segments the digital signal processing into two distinct stages: OAM mode demultiplexing (separating different OAM modes from the composite signal) and stream demultiplexing (separating individual data streams within each OAM mode). This segmentation allows parallel processing of multiple OAM modes simultaneously, reducing the overall processing burden compared to handling all streams sequentially in a single stage.
Solution Approach 2:
The patent introduces a two-dimensional processing structure where the first dimension handles OAM mode separation and the second dimension handles stream separation. This dimensional organization transforms the processing architecture from a flat single-stage approach to a hierarchical two-stage approach, enabling more efficient resource utilization and reduced processing complexity at each stage.
2Productivity
If higher-order OAM modes are used to increase the number of multiplexed streams, then the transmission capacity is improved, but the reception power is reduced
Solution Approach 1:
The patent employs partial action by selectively using only the necessary number of OAM modes based on channel conditions and required transmission capacity. Instead of always using the maximum number of available OAM modes, the system dynamically adjusts the number of active modes to achieve the minimum required capacity, thereby avoiding the reception power loss associated with using higher-order modes when they are not strictly necessary.
3Area of stationary object
If the transmission distance is increased to expand coverage area, then the coverage is improved, but the reception power decreases due to signal attenuation
Solution Approach 1:
The patent changes key transmission parameters including the number of active OAM modes, modulation schemes, and power allocation based on detected channel conditions. When transmission distance increases and channel quality deteriorates, the system adjusts parameters such as reducing to lower-order OAM modes with better power efficiency, changing modulation to more robust schemes, and reallocating power to maintain reception quality over extended distances.
4Productivity
If the number of UCAs is increased to generate more OAM modes, then the number of multiplexed streams is improved, but the device complexity is increased
Solution Approach 1:
The patent makes each UCA universal by enabling it to generate multiple different OAM modes through dynamic phase control of its antenna elements. Instead of requiring one dedicated UCA per OAM mode, each UCA can be reconfigured to generate any required OAM mode, allowing a smaller number of multi-functional UCAs to replace a larger number of single-functional UCAs, thereby reducing overall system complexity.
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 minimizes signal processing demands for demultiplexing and maintains or increases transmission capacity by allowing more multiplexed streams while reducing the impact of increased transmission distance on reception power, thereby enhancing overall system performance.
Implementation Method 1
a spatial multiplex transmission technique for a radio signal using OAM has been reported... electromagnetic wave having OAM, an equiphase surface thereof is distributed in a spiral form along a propagation direction centering a propagation axis
Data Source
AI summary
In an OAM multiplexing communication system in which an M-UCA is provided in each of a transmitting station and a receiving station, signals in a plurality of OAM modes are generated and transmitted from each UCA of the transmitting station, signals in the plurality of OAM modes are received and demultiplexed by each UCA of the transmitting station, and streams of the number of UCAs×the number of OAM modes are subjected to spatial multiplex transmission, in which the transmitting station includes a signal processing unit generating the streams to be transmitted in the plurality of OAM modes from each of the UCAs of the M-UCA, and the receiving station includes a signal processing unit receiving the signals in the plurality of OAM modes demultiplexed by each of the UCAs of the M-UCA, and demultiplexes the received signals for each stream from signals in an identical OAM mode.