OAM MIMO Beamforming Vectors for Communication Capacity
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Solution Overview
Problem
Current multiple-input multiple-output (MIMO) communication technologies, such as those employed in 5G New Radio (NR), face challenges in improving beamforming efficiency, particularly in achieving multiple degrees of freedom for MIMO transmissions.
Innovation Solution
The method involves selecting an azimuth mode and a corresponding radial mode for OAM MIMO communication. The azimuth mode defines a discrete Fourier transform (DFT) vector, and the radial modes define beamforming vectors that include the DFT vector weighted and repeated, ensuring orthogonality between the vectors.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If conventional MIMO beamforming is used, then communication coverage is provided, but beamforming efficiency and communication capacity are limited
Solution Approach 1:
The patent introduces OAM (orbital angular momentum) modes as an additional dimension beyond conventional spatial beamforming. By multiplexing signals across different OAM modes (radial and azimuthal components) in addition to traditional spatial beams, the system achieves multiple degrees of freedom for MIMO transmissions, thereby increasing communication capacity and beamforming efficiency simultaneously
2Productivity
If more antenna elements are added to increase MIMO capacity, then communication efficiency improves, but system complexity increases
Solution Approach 1:
The patent makes the antenna elements multi-functional by enabling them to perform both conventional MIMO beamforming and OAM mode generation. The same antenna array is configured to support multiple OAM modes through specific excitation patterns, allowing the system to achieve enhanced capacity without adding separate dedicated components for each function
Data Source
AI summary
An example aspect comprises selecting an azimuth mode for an OAM MIMO transmission by a transmitter that includes a first number of circles that each include a second number of antenna elements, wherein the azimuth mode defines a DFT vector of a size less than or equal to the second number; selecting, from a plurality of radial modes associated with the azimuth mode, a radial mode for the transmission, wherein the radial modes include at least a first radial mode defining a first beamforming vector and a second radial mode defining a second beamforming vector, wherein each one of the first and second beamforming vectors includes the DFT vector weighted and repeated for a number of times less than or equal to the first number, wherein the first and second beamforming vectors are orthogonal to each other; and transmitting a signal using a beam configured according to the radial mode.