OAM Mode Separation for Inter-Mode Interference Suppression
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing OAM multiplexing communication systems face challenges in separating signals due to deviations in the alignment of transmitting and receiving UCAs and interference from reflected waves, leading to deteriorated communication quality and increased circuit and processing complexity.
Innovation Solution
The system employs a configuration with concentrically disposed UCAs and includes signal processing units that estimate and equalize channel information for each OAM mode, calculating receiving and transmitting weights to mitigate inter-mode interference, thereby simplifying digital signal processing and reducing circuit complexity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional full MIMO method is used to perform precoding and equalization for all signal sequences, then communication quality can be maintained, but circuit scale and digital signal processing amount are exponentially increased
Solution Approach 1:
The patent segments the signal processing by separating OAM mode separation from general MIMO processing. The OAM mode separation unit specifically handles OAM mode decomposition using the known channel matrix structure, while the MIMO processing unit handles the remaining signal sequences. This segmentation reduces the dimensionality of the processing required for each unit, thereby reducing circuit scale and digital signal processing complexity while maintaining communication quality.
2Reliability
If conventional full MIMO method is used to perform precoding and equalization for all signal sequences, then communication quality can be maintained, but digital signal processing amount is exponentially increased
Solution Approach 1:
The patent segments the signal processing by separating OAM mode separation from general MIMO processing. The OAM mode separation unit specifically handles OAM mode decomposition using the known channel matrix structure, while the MIMO processing unit handles the remaining signal sequences. This segmentation reduces the dimensionality of the processing required for each unit, thereby reducing circuit scale and digital signal processing complexity while maintaining communication quality.
3Adaptability or versatility
If transmitting UCA and receiving UCA are disposed at fixed positions deviated from front facing disposition, then system adaptability is improved, but inter-mode interference increases and communication quality deteriorates
Solution Approach 1:
The patent applies preliminary action by pre-calculating and utilizing the specific structure of the channel matrix that arises from deviations in UCA positioning. The system incorporates position deviation information into the channel matrix construction before signal processing occurs, allowing the OAM mode separation unit to compensate for the expected interference patterns. This preliminary structuring of the channel matrix enables the system to maintain communication quality despite position deviations, thus resolving the contradiction between adaptability and reliability.
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 effectively suppresses inter-mode interference and improves system capacity with a reduced digital signal processing load, even in non-ideal alignment conditions and with the presence of reflected waves.
Implementation Method 1
subjects a radio signal to spatial multiplex transmission by using orbital angular momentum (OAM) of an electromagnetic wave
Data Source
AI summary
An OAM multiplexing communication system uses one or more OAM modes and multiplexes signals of one or more sequences for each OAM mode. A transmitting station includes a transmitting antenna using an M-UCA, and an OAM mode generation unit that simultaneously generates one or more OAM modes from each UCA. A receiving station includes a receiving antenna equivalent to the M-UCA, an OAM mode separation unit that separates signals received by each UCA for each OAM mode, and a received signal processing unit that estimates channel information for each OAM mode and performs an equalization process for each OAM mode by using a receiving weight calculated from the channel information. The received signal processing unit is configured to estimate, for each OAM mode, channel information of another OAM mode causing interference and calculate the receiving weight of a subject OAM mode by using the channel information of the subject OAM mode and said another OAM mode.