Better connectivity in distant areas: a Ka-band transceiver for satellite tv for pc communication
PICTURE: The test chip measures only 3 mm x 3 mm. view More
Photo credit: IEEE Radio Frequency Integrated Circuits Symposium 2020
Scientists from the Tokyo Institute of Technology and Socionext Inc. have developed a novel transceiver that enables seamless communication between earth platforms and satellites in lower, medium and geostationary orbits of the earth. This transceiver could provide the Internet to people in remote rural areas and at sea, among other things.
We live in the information age, in which communication technologies have made unprecedented progress. However, it remains difficult to make connections to remote locations such as rural areas or the open sea. Satellite communications (SATCOM) is an attractive option for providing data links to such locations. However, for SATCOM to be effective, the right equipment must be available both in space and here on Earth.
At the forefront of research to achieve a superior SATCOM are scientists from Prof. Kenichi Okada’s laboratory at the Tokyo Institute of Technology (Tokyo Tech) who have developed a novel transceiver for SATCOM using standard CMOS Technology. This transceiver works in the “Ka-Band”, which means for SATCOM a frequency range of 27 to 31 GHz for uplink (ground to satellite) and a range of 17 to 21 GHz for downlink (satellite to ground).
Its design is characterized by a variety of features that set it apart from the competition. A high quality factor transformer is used on the transmitter side (TX) to achieve efficient power consumption and high linearity in transmission, resulting in less distortion during transmission. The receiver side (RX) has a two-channel architecture that enables several functions.
First, having two channels of reception enables signals from two satellites to be received at the same time. These signals are received in parallel with either two independent polarization modes or two different frequencies. In addition, the proposed design can perform adjacent channel interference suppression; that is, the “contamination” of a signal received on one channel by another signal in an adjacent frequency band is removed using information received on the other channel. This strategy increases the dynamic range of the system and enables it to work correctly even in non-ideal scenarios with high levels of noise and interference.
Both TX and RX perform direct conversion of a signal. That is, the TX converts a baseband signal directly into a modulated signal and the RX performs the inverse process without additional intermediate frequency conversions, in contrast to the commonly used heterodyne receivers. This significantly reduces the overall complexity, size, and power consumption of the transceiver.
Scientists created a prototype chip to test the actual performance of their design when all of the modulation schemes regulated by the SATCOM DVB-S2X standard were used. This includes higher order modulation techniques such as 64 APSK and 256 APSK that deliver fast data rates.
The results of the performance tests are very encouraging, especially when compared to other existing SATCOM transceivers, putting this novel design on the card. Prof. Okada notes, “Our paper introduces the first Ka-band SATCOM transceiver implemented using standard CMOS technology and designed for ground platform communication with geostationary satellites and satellites with low earth orbit.”
These orbits are 35,786 km and 200-2,000 km, respectively. Communicating with satellites that are far from a 3 x 3 mm chip is certainly not an easy task.
For years, Prof. Okada’s lab has developed various types of state-of-the-art transceivers for next-generation technologies, including 5G applications, devices that enable the Internet of Things, and low-power Bluetooth communications. This latest transceiver is another piece of the puzzle that enables seamless global connectivity. “Satellite communications has become a key technology for providing interactive TV and broadband Internet services in rural, low-density areas. Implementing Ka-band communications using silicon – specifically CMOS technology – is because of the potential for a global coverage a promising solution Low costs and use of the wide available bandwidth “, says Prof. Okada.
Let’s hope the efforts of these Tokyo Tech researchers will help more people benefit from instant communication in the current information age.
 Transceiver: A device that can send and receive signals
 CMOS: Complementary Metal Oxide Semiconductor; A modern manufacturing process for transistors that is widely used for large scale integrated circuits
 Baseband signal: A signal in its “pure” form with its original frequency without modulation
 Modulated Signal: A coded signal that carries all of the information in a baseband signal, usually at a higher frequency to facilitate transmission
 APSK: amplitude and phase shift keying; describes a modulation technique in which a baseband signal is encoded in both phase and amplitude of a carrier signal
About the Tokyo Institute of Technology
Tokyo Tech is at the forefront of research and higher education as the leading science and technology university in Japan. Tokyo Tech researchers excel in areas that range from materials science to biology, computer science and physics. Tokyo Tech was founded in 1881 and is home to over 10,000 undergraduate and graduate students annually who develop into scientific leaders and some of the most sought-after engineers in the industry. The Tokyo Tech Community embodies the Japanese philosophy of “Monotsukuri”, which means “technical ingenuity and innovation,” and strives to contribute to society through effective research.
Socionext is a global, innovative company that designs, develops and delivers system-on-chip solutions for customers worldwide. The company focuses on technologies that drive today’s cutting edge consumer, automotive, and industrial applications. Socionext combines world-class know-how, experience and an extensive IP portfolio to provide exceptional solutions and ensure customers a better quality of experience. Socionext Inc. was founded in 2015 and is headquartered in Yokohama. The company has offices in Japan, Asia, the United States and Europe to lead product development and sales. More information is available at https://www.socionext.com.
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