Wireless Communication at 310 GHz using GaAs High-Electron-Mobility Transistors for Detection

Blin, Stephane,Tohme, Lucie,Coquillat, Dominique,Horiguchi, Shogo,Minamikata, Yusuke,Hisatake, Shintaro,Nouvel, Philippe,Cohen, Thomas,Penarier, Annick,Cano, Fabrice,Varani, Luca,Knap, Wojciech,Nagats The Korea Institute of Information and Commucation 2013 Journal of communications and networks Vol.15 No.6

We report on the first error-free terahertz (THz) wireless communication at 0.310 THz for data rates up to 8.2 Gbps using a 18-GHz-bandwidth GaAs/AlGaAs field-effect transistor as a detector. This result demonstrates that low-cost commercially-available plasma-wave transistors whose cut-off frequency is far below THz frequencies can be employed in THz communication. Wireless communication over 50 cm is presented at 1.4 Gbps using a uni-travelling-carrier photodiode as a source. Transistor integration is detailed, as it is essential to avoid any deleterious signals that would prevent successful communication. We observed an improvement of the bit error rate with increasing input THz power, followed by a degradation at high input power. Such a degradation appears at lower powers if the photodiode bias is smaller. Higher-data-rate communication is demonstrated using a frequency-multiplied source thanks to higher output power. Bit-error-rate measurements at data rates up to 10 Gbps are performed for different input THz powers. As expected, bit error rates degrade as data rate increases. However, degraded communication is observed at some specific data rates. This effect is probably due to deleterious cavity effects and/or impedance mismatches. Using such a system, realtime uncompressed high-definition video signal is successfully and robustly transmitted.

Wireless Communication at 310 GHz Using GaAs High-Electron-Mobility Transistors for Detection

Stéphane Blin,Lucie Tohme,Dominique Coquillat,Shogo Horiguchi,Yusuke Minamikata,Shintaro Hisatake,Philippe Nouvel,Thomas Cohen,Annick Pénarier,Fabrice Cano,Luca Varani,Wojciech Knap,Tadao Nagatsuma 한국통신학회 2013 Journal of communications and networks Vol.15 No.6

We report on the first error-free terahertz (THz) wirelesscommunication at 0.310 THz for data rates up to 8.2 Gbps using a18-GHz-bandwidth GaAs/AlGaAs field-effect transistor as a detector. This result demonstrates that low-cost commercially-availableplasma-wave transistors whose cut-off frequency is far below THzfrequencies can be employed in THz communication. Wirelesscommunication over 50 cm is presented at 1.4 Gbps using a unitravelling-carrier photodiode as a source. Transistor integration isdetailed, as it is essential to avoid any deleterious signals that wouldprevent successful communication. We observed an improvementof the bit error rate with increasing input THz power, followed bya degradation at high input power. Such a degradation appearsat lower powers if the photodiode bias is smaller. Higher-dataratecommunication is demonstrated using a frequency-multipliedsource thanks to higher output power. Bit-error-ratemeasurementsat data rates up to 10 Gbps are performed for different inputTHz powers. As expected, bit error rates degrade as data rate increases. However, degraded communication is observed at somespecific data rates. This effect is probably due to deleterious cavityeffects and/or impedance mismatches. Using such a system, realtimeuncompressed high-definition video signal is successfully androbustly transmitted.

심층강화학습 기반 차량 대 차량 자원 할당 기법

문지훈,심병효 한국통신학회 2022 韓國通信學會論文誌 Vol.47 No.10

In this paper, we propose a deep reinforcement learning (DRL)-based method to satisfy diverse requirements in vehicular communications. Using the channel as the input, the actor-critic algorithm outputs the resource allocation maximizing the network sum rate while ensuring the requirements. 본 논문에서는 차량 간 통신에서 다양한 요구 조건을 만족하기 위해 심층강화학습을 사용하는 방안을제시한다. 심층강화학습 중 actor-critic 알고리즘을 활용해 주변 채널 상황을 입력으로 받아 자원 할당을출력해 차량 별 요구 조건을 만족하면서 네트워크 데이터 전송률 합을 최대화한다.

Towards 6G: Key technological directions

Chamitha De Alwis,Pardeep Kumar,Quoc-Viet Pham,Kapal Dev,Anshuman Kalla,Madhusanka Liyanage,Won-Joo Hwang 한국통신학회 2023 ICT Express Vol.9 No.4

Sixth-generation mobile networks (6G) are expected to reach extreme communication capabilities to realize emerging applications demanded by the future society. This paper focuses on six technological directions towards 6G, namely, intent-based networking, THz communication, artificial intelligence, distributed ledger technology/blockchain, smart devices and gadget-free communication, and quantum communication. These technologies will enable 6G to be more capable of catering to the demands of future network services and applications. Each of these technologies is discussed highlighting recent developments, applicability in 6G, and deployment challenges. It is envisaged that this work will facilitate 6G related research and developments, especially along the six technological directions discussed in the paper.

Hybrid Beamforming in Sub-THz LoS MIMO Systems

윤채원,최계원 한국통신학회 2023 韓國通信學會論文誌 Vol.48 No.5

In this study, we design a hybrid beamforming algorithm for sub-terahertz-band communications. We introduce a near-field propagation model for an indoor line-of-sight environment. A hybrid beamforming method for sparse arrays of subarray structures is proposed. Using MATLAB simulation results, we show that the proposed algorithm achieves high capacity.

Performance Analysis of Multi-Gigabit Wireless Transmission at THz WLAN-Type Applications

최용훈 한국통신학회 2014 Journal of communications and networks Vol.16 No.3

Optimal position of access point (AP) is important for multi-gigabit wireless transmission in terahertz (THz) wireless local area network (WLAN)-type applications, where there exist the THz characteristic multiple clusters in channel propagation. By considering the multiple clusters in THz indoor communications, this paper investigates the optimal AP position when two APs are issued for increasing the system capacity. Numerical results reveal that the central position of each AP within each half service region, which offers the shortest cumulated path length for line-of-sight paths, is optimal to achieve the maximal system capacity.

THz 실내 무선 통신시스템을 위한 전파환경 분석

이원희,정태진 한국인터넷방송통신학회 2010 한국인터넷방송통신학회 논문지 Vol.10 No.2

근거리 무선 통신시스템은 사무실과 가정의 응용으로 빠르게 확장하고 있다. 무선 네트워크의 개발은 더 높은 data rate의 요구를 만족하도록 수행되었다. 이것으로 높은 주파수에서 동작하는 통신시스템 개발의 필요성이 강조된다. 따라서 근거리 무선 통신 네트워크는 테라헤르츠 주파수 쪽으로 옮겨갈 것으로 기대된다. 실내의 벽과 바닥, 천장에 의해 발생하는 전파 환경 분석은 3차원 광선방출기법을 이용하였다. 또한 테라헤르츠 주파수에서의 rough한 건물 벽면의 특성을 파악하기 위해 광학적으로 두꺼운 smooth한 건물 재질의 반사 모델로부터 접근하여 나타내었다. 전파환경 시뮬레이션 결과평균 수신 전력이 참고문헌의 결과와 유사한 결과를 얻을 수 있었다. 또한, 실내 공간의 크기가 6m(L)×5m(W)×2.5m(H)에서 콘크리트 벽의 경우 RMS 지연시간은 9.11 ns로 계산되었다. Short-range wireless communication systems are expanding at rapid rate, finding application in offices and homes. Development of wireless local network is accompanied by steady increase in the demand for ever higher data rates. This in turn entails the necessity to develop communication systems which operate at higher frequencies. It can be expected that short-rage wireless communication networks will soon push towards the THz frequency range. We use a 3D ray-launching for analysis of propagation environments at the indoor fixtures. We extended the approach from the modeling of the reflectivity of optically thick, smooth building materials at THz frequencies to materials with a rough surface. The simulation result of propagation environment is similar to average received power of reference paper. The RMS delay spread was calculated to be 9.11 ns in a room size of 6m(L)×5m(W)×2.5m(H) for the concrete plaster.

Performance Comparison of Single-Carrier and Multi-Carrier Systems in a Terahertz Wireless Communication Environment

Derek Kwaku Pobi Asiedu,Roger Kwao Ahiadormey2,신수호,이경재 한국정보기술학회 2019 JOURNAL OF ADVANCED INFORMATION TECHNOLOGY AND CON Vol.9 No.1

This paper investigates the performance comparison of a Terahertz (THz) communications for a single-carrier and a multi-carrier single antenna point-to-point communication system. The multi-carrier system and single carrier system consider the orthogonal frequency division multiplexing (OFDM) and the minimum mean square error linear equalizer (MMSE-LE), respectively. We compare the frame-error-rate (FER) and throughput performance of both the systems for a THz communication environment with the carrier frequency of 300GHz and the tapped delay line (TDL) channel models described in 3GPP. It is observed from the simulation results that the OFDM systems outperform the MMSE-LE for various configurations.

Ultra Broadband Indoor Channel Measurements and Calibrated Ray Tracing Propagation Modeling at THz Frequencies

Priebe, Sebastian,Kannicht, Marius,Jacob, Martin,Kurner, Thomas The Korea Institute of Information and Commucation 2013 Journal of communications and networks Vol.15 No.6

Ultra broadband communication systems operated at THz frequencies will require the thorough knowledge of the propagation channel. Therefore, an extensive measurement campaign of 50 GHz wide indoor radio channels is presented for the frequencies between 275 and 325 GHz. Individual ray paths are resolved spatially according to angle of arrival and departure. A MIMO channel is recorded in a $2{\times}2$ configuration. An advanced frequency domain ray tracing approach is used to deterministically simulate the THz indoor propagation channel. The ray tracing results are validated with the measurement data. Moreover, the measurements are utilized for the calibration of the ray tracing algorithm. Resulting ray tracing accuracies are discussed.

Ultra Broadband Indoor Channel Measurements and Calibrated Ray Tracing Propagation Modeling at THz Frequencies

Sebastian Priebe,Marius Kannicht,Martin Jacob,Thomas Kürner 한국통신학회 2013 Journal of communications and networks Vol.15 No.6

Ultra broadband communication systems operated atTHz frequencies will require the thorough knowledge of the propagationchannel. Therefore, an extensive measurement campaignof 50 GHz wide indoor radio channels is presented for the frequenciesbetween 275 and 325 GHz. Individual ray paths are resolvedspatially according to angle of arrival and departure. A MIMOchannel is recorded in a 2×2 configuration. An advanced frequency domain ray tracing approach is usedto deterministically simulate the THz indoor propagation channel. The ray tracing results are validated with the measurement data. Moreover, the measurements are utilized for the calibration of theray tracing algorithm. Resulting ray tracing accuracies are discussed.