The article discusses the features of training radio specialists for sea transport, taking into account international and national requirements for the qualifications of seafarers. It is emphasized ...that only persons who have diplomas and qualification certificates of the established form are allowed to occupy the positions of ship’s crew members. As part of the study, qualification documents were systematized for a GMDSS limited area operator, GMDSS operator, GMDSS second class radio electronics, radiotelephone operator and GMDSS first class radio electronics. The areas, types and tasks of the professional activity of the graduates of the educational program “Radio communication and electrical radio navigation of the marine fleet” have been determined. Among the main objects of professional activity, radio-electronic equipment on ships and coastal centers of sea and water transport is highlighted. It was emphasized that the results of training specialists are assessed by the acquired universal, general professional and professional competencies, i.e. the ability to apply knowledge, skills and personal qualities in accordance with the tasks of professional activity. The article examines modern trends in determining the quality of education by using internal and external assessments. It is concluded that the training of radio specialists for maritime transport in modern conditions is of great importance, especially taking into account the development of transportation along the Northern Sea Route and the industrial development of the Arctic. At the same time, the defining condition is the inclusion of international and national requirements in the educational process, then graduates in the field of radio communication and electric radio navigation of the marine fleet will be in demand in the Russian and foreign freight market.
Almost 15 years have passed since the initial demonstrations of terahertz (THz) wireless communications were made using both pulsed and continuous waves. THz technologies are attracting great ...interest and are expected to meet the ever-increasing demand for high-capacity wireless communications. Here, we review the latest trends in THz communications research, focusing on how photonics technologies have played a key role in the development of first-age THz communication systems. We also provide a comparison with other competitive technologies, such as THz transceivers enabled by electronic devices as well as free-space lightwave communications.
The design of a radio communication system employing orbital angular momentum (OAM) mode multiplexing is described. Rotman lenses followed by circular antenna arrays are used to transmit and receive ...radio frequency beams carrying OAM. In our experiment, two 3 × 3 Rotman lenses are fabricated to feed the three-element circular arrays with certain phase gradients for OAM modes multiplexing and demultiplexing. The OAM-carrying beams of mode number l = +1, 0, and -1 are generated at 9.7 GHz, with each channel carrying an independent data stream of 40 Mbit s -1 quadrature phase shift keying signal in a bandwidth of 20 MHz. And all three channels are recovered with bit error rates below the forward error correction limit of 3.8 × 10 -3 .
Nonreciprocal microwave devices are ubiquitous in radar and radio communication and indispensable in the readout chains of superconducting quantum circuits. Since they commonly rely on ferrite ...materials requiring large magnetic fields that make them bulky and lossy, there has been significant interest in magnetic-field-free on-chip alternatives, such as those recently implemented using the Josephson nonlinearity. Here, we realize reconfigurable nonreciprocal transmission between two microwave modes using purely optomechanical interactions in a superconducting electromechanical circuit. The scheme relies on the interference in two mechanical modes that mediate coupling between the microwave cavities and requires no magnetic field. We analyse the isolation, transmission and the noise properties of this nonreciprocal circuit. Finally, we show how quantum-limited circulators can be realized with the same principle. All-optomechanically mediated nonreciprocity demonstrated here can also be extended to directional amplifiers, and it forms the basis towards realizing topological states of light and sound.Nonreciprocal optical devices traditionally rely on magnetic fields and magnetic-free approaches are rather recent. Here, Bernier et al. propose and demonstrate a purely optomechanical circulator with reconfigurable transmission without the need for direct coupling between input and output modes.
This paper describes a QAM signal evaluation method in a radio communication evaluation system based on under-sampling. Although frequency elements generated by quadrature demodulation can be ...calculated using QAM symbols on a constellation, this technique requires a symbol synchronous trigger. Our proposed method has a software triggering technique that can extract the symbols regardless of the frequency difference. Numerical simulation with 16QAM showed good synchronization between the trigger and the measured waveforms. In addition, the results of demonstration experiment using 16QAM with carrier frequency of 28 GHz showed the practicality of the proposed method by drawing an eye pattern and a constellation. In conclusion, we show the possibility of high-resolution and low-cost measurement in QAM signals with mmWave carrier frequency.
Cell-free massive MIMO and symbiotic radio communication have been recently proposed as the promising beyond fifth-generation (B5G) networking architecture and transmission technology, respectively. ...To reap the benefits of both, this paper studies cell-free symbiotic radio communication systems, where a number of cell-free access points (APs) cooperatively send primary information to a receiver, and simultaneously support the passive backscattering communication of the secondary backscatter device (BD). We first derive the achievable communication rates of the active primary user and passive secondary user under the assumption of perfect channel state information (CSI), based on which the transmit beamforming of the cell-free APs is optimized to characterize the achievable rate-region of cell-free symbiotic communication systems. Furthermore, to practically acquire the CSI of the active and passive channels, we propose an efficient channel estimation method based on two-phase uplink-training, and the achievable rate-region taking into account CSI estimation errors is further characterized. Simulation results are provided to show the effectiveness of our proposed beamforming and channel estimation methods.
Recently, much attention has been focused on beams carrying orbital angular momentum (OAM) for radio communication. Here we experimentally demonstrate a planar-spiral phase plate (planar-SPP) for ...generating arbitrary mixed OAM beams. This proposed planar-SPP uses the concept of transmit array antenna having a perforated substrate to control the outputting phase for generating beams carrying OAM with arbitrary modes. As demonstrations, three planar-SPPs with a single OAM mode and two mixed OAM modes around 94 GHz have been investigated with design and experiments in this paper, respectively. The typical experimental intensity and phase patterns show that the proposed method of generating OAM beams really works.
We compare the technique of using the orbital angular momentum (OAM) of radio waves for generating multiple channels in a radio communication scenario with traditional multiple-in-multiple-out (MIMO) ...communication methods. We demonstrate that, for certain array configurations in free space, traditional MIMO theory leads to eigen-modes identical to the OAM states. From this we conclude that communicating over the sub-channels given by OAM states is a subset of the solutions offered by MIMO, and therefore does not offer any additional gains in capacity.
We conduct an in depth study on the performance of deep learning based radio signal classification for radio communications signals. We consider a rigorous baseline method using higher order moments ...and strong boosted gradient tree classification, and compare performance between the two approaches across a range of configurations and channel impairments. We consider the effects of carrier frequency offset, symbol rate, and multipath fading in simulation, and conduct over-the-air measurement of radio classification performance in the lab using software radios, and we compare performance and training strategies for both. Finally, we conclude with a discussion of remaining problems, and design considerations for using such techniques.
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