Greater connectedness in remote areas: A Ka-band transceiver for satellite communications

EurekAlert  August 4, 2020 The transceiver developed by researchers in Japan using standard CMOS technology uses 27-31 GHz frequency range for uplink and 17-21 GHz range for downlink. A high-quality transformer is used to achieve efficient power use and high linearity in transmission, resulting in lower distortion during transmission. Two RX channels allows for receiving signals from two satellites simultaneously in parallel using either two independent polarization modes or two different frequencies. It can perform adjacent-channel interference cancellation increasing the dynamic range of the system, thus allowing it to operate correctly even in less-than-ideal scenarios with stronger noise and interference. […]

Researchers Use Lasers to Bring the Internet Under the Sea

IEEE Spectrum  June 22, 2020 Researchers in Saudi Arabia have developed underwater WiFi which they call Aqua-Fi. The system is fully compliant with IEEE 802.11 wireless standards. A Wi-Fi signal was used to connect the device to a Raspberry Pi functioning as a modem. The modem converted the wireless signal to an optical signal (in this case, a laser) that was beamed to the receiver attached to a surface buoy. From there, established communications techniques were used to send the signal to an orbiting satellite. For the underwater device to receive data, the process is simply reversed. The system is […]

Long-range Communications without Large, Power-Hungry Antennas

DARPA News  June 9, 2020 To break the dependence on big antennas and amplifiers for establishing long-range tactical communications for U.S. troops in remote locations, DARPA recently announced the Resilient Networked Distributed Mosaic Communications (RN DMC) program which aims to provide long-range communications through “mosaic” antennas composed of spatially distributed low SWaP-C transceiver elements or “tiles.” This approach replaces high-powered amplifiers and large directional antennas with mosaics of dispersed tile transceivers. Transmit power is distributed among the tiles, and gain is achieved through signal processing rather than by a physical antenna aperture to concentrate energy. The antenna mosaic concept could […]

Formula may help 5G wireless networks efficiently share communications frequencies

Science Daily  May 26, 2020 Researchers at NIST have developed a formula using Q-learning technique which enables transmitters to rapidly select the best subchannels for successful and simultaneous operation of Wi-Fi and License Assisted Access (LAA) networks in unlicensed bands. The transmitters each learn to maximize the total network data rate without communicating with each other. The scheme rapidly achieves overall performance that is close to the result based on exhaustive trial-and-error channel searches. The formula takes into account multiple network layers, the physical equipment and the channel access rules between base stations and receivers. The study addressed indoor scenarios, […]

New devices produce and detect twisted light

Physics World  May 19, 2020 Development of a dynamically tunable OAM light source is a critical step in the realization of OAM modulation and multiplexing. An international team of researchers (USA – University of Pennsylvania, Northeastern University, Italy, Spain) harnessed the properties of total momentum conservation, spin-orbit interaction, and optical non-Hermitian symmetry breaking, demonstrated an OAM-tunable vortex microlaser, providing chiral light states of variable topological charges at a single telecommunication wavelength. The scheme can be further scaled up for simultaneous multivortex emissions in a flexible manner. The work provides a route for the development of the next generation of multidimensional […]

Magnetoacoustic waves: Towards a new paradigm of on-chip communication

Phys.org  April 6, 2020 An international team of researchers (Spain, Germany) designed an experiment to image and quantify the magnetization dynamics generated by SAW. The results clearly showed that magnetization waves exist at distinct frequencies and wavelengths and that it is possible to create wave interferences. The interference patterns of magnetization waves provide new avenues for manipulation of these waves at room temperature. As magnetization waves are coupled to the acoustic waves, they can travel long distances and have larger amplitudes than spin waves. As magnetoacoustic waves have more energy efficiency and larger spatial extension they are considered potential information […]

Extreme high-frequency signals enable terabits-per-second data links

Phys.com  March 31, 2020 A team of researchers in the US (Brown University, industry) tested sending extremely high-frequency 200 GHz signals through a device with two wires running parallel inside a sheath with a large diameter that facilitates increased mixing of the waveguide modes. These mixtures enable the transmission of parallel noninterfering data channels. They demonstrated that the waveguide could support a data rate of 10 terabits per second. Their work demonstrates the feasibility of this approach to high-rate data transmission…read more.

Physicist from Hannover develops new photon source for tap-proof communication

EurekAlert  March 27, 2020 Sources of entangled photons have been realized mainly in the near-infrared 700- to 1550-nm spectral window. Using custom-designed lithium niobate crystals for spontaneous parametric down-conversion and tailored superconducting nanowire single-photon detectors an international team of researchers (UK, Japan, Germany) has demonstrated two-photon interference and polarization-entangled photon pairs at 2090 nm. These results open the 2- to 2.5-μm mid-infrared window for the development of optical quantum technologies such as quantum key distribution in next-generation mid-infrared fiber communication systems and future Earth-to-satellite communications much more secure in the future….read more. Open Access TECHNICAL ARTICLE

World record transmission of 172 Tb/s over 2040km distance coupled-3-core multi-core fiber

EurekAlert  April 2, 2020 Using the product of data-rate and distance as a general index of transmission capacity, researchers in Japan achieved 351 petabit/s x km, more than doubling the current world record in standard outer diameter optical fibers employing space-division multiplexing. The coupled-core multi-core fiber requires signal processing on the receiving side after transmission, but the signal processing load is less compared to more commonly investigated few-mode fibers. The fiber has the same outer diameter as standard optical fibers which allows converting such a fiber into a cable with existing technologies and equipment, simplifying a timely adoption of coupled-core […]

Li-Fi Scrubs Into the Operating Room

IEEE Spectrum  March 13, 2020 An international team of researchers (Germany, Czech Republic) set up multiple Li-Fi transmitters and receivers in a neurosurgery operating room in Prague. In a series of tests, the Li-Fi system managed to transfer data quickly and without complete signal loss. They achieved data rates of up to 600 megabits per second. Because Li-Fi uses higher-frequency light than Wi-Fi does, it could, in theory, have a higher bandwidth and therefore transmit data more quickly. Unlike Wi-Fi’s radio frequencies, which can pass through walls, optical light is easily blocked by humans or objects. To get around this […]