We propose an indoor network with a sub-terahertz- band wireless link for 6G applications. In our proposed indoor network, an optical hub unit (OHU) that controls the entire system is optically linked to THz remote nodes (RNs) over optical distribution fibers. The THz RNs communicate with the user equipment through a sub-THz wireless link. The function of the THz RNs is to provide an interface between the optical link and the sub-THz wireless link. For downlink transmission, a photonics-based sub-THz-band signal generation method is adopted to take advantage of the broadband characteristics of the optical components. An electronics-based sub-THz mixer is also used for uplink transmission because of its cost-effectiveness and low energy consumption. A digital signal processor (DSP) is designed to recover the original transmitted baseband signal. The DSP provides frequency offset compensation over a wide frequency range and reduces the probability of cyclic slip. The performance of the proposed system was investigated experimentally with commercially available optical/electrical components. We demonstrate 100 Gb/s 2.5-m wireless transmission with a 16-quadrature amplitude modulation (16-QAM) signal for configuring the downlink. The optical transmission distance was set to 10 km, and the power penalty measured by optical transmission was negligible. We also investigated the scalability and tunability of the photonics-based sub-THz transmitter to confirm the upgradability of our proposed indoor network to consider future capacity expansion. To establish an uplink, a 25 Gb/s 1.5-m wireless transmission with a quadrature phase shift keying (QPSK) signal was employed. A directly modulated laser was used for cost-effective optical transmission. Unlike downstream transmission, a measured bit error rate (BER) penalty caused by the optical transmission was observed. This is due to the interplay between the frequency chirp of the directly modulated laser and the chromatic dispersion in the fiber. Despite this penalty, BERs less than the soft-decision forward error correction (FEC) threshold (2 × 10-2) with 20% overhead were achieved. We discuss several remaining technical challenges in real-field deployment. These include THz Tx power improvement, photonic integration, reducing form-factor, polarization insensitivity, and automatic beam steering. Our recent efforts to address these issues are also introduced and examined.
KSP 제안 키워드
100 Gb/s, 16 quadrature amplitude modulation(16QAM), Bit Error Rate(And BER), Capacity expansion, Chromatic dispersion(CD), Cost-effectiveness, Cyclic slip, Digital signal processor(DSP), Directly modulated laser(DML), Electrical components, Form factor
본 저작물은 크리에이티브 커먼즈 저작자 표시 (CC BY) 조건에 따라 이용할 수 있습니다.
저작권정책 안내문
한국전자동신연구원 지식공유플랫폼 저작권정책
한국전자통신연구원 지식공유플랫폼에서 제공하는 모든 저작물(각종 연구과제, 성과물 등)은 저작권법에 의하여 보호받는 저작물로 무단복제 및 배포를 원칙적으로 금하고 있습니다. 저작물을 이용 또는 변경하고자 할 때는 다음 사항을 참고하시기 바랍니다.
저작권법 제24조의2에 따라 한국전자통신연구원에서 저작재산권의 전부를 보유한 저작물의 경우에는 별도의 이용허락 없이 자유이용이 가능합니다. 단, 자유이용이 가능한 자료는 "공공저작물 자유이용허락 표시 기준(공공누리, KOGL) 제4유형"을 부착하여 개방하고 있으므로 공공누리 표시가 부착된 저작물인지를 확인한 이후에 자유이용하시기 바랍니다. 자유이용의 경우에는 반드시 저작물의 출처를 구체적으로 표시하여야 하고 비영리 목적으로만 이용이 가능하며 저작물을 변형하거나 2차 저작물로 사용할 수 없습니다.
<출처표시방법 안내> 작성자, 저작물명, 출처, 권호, 출판년도, 이용조건 [예시1] 김진미 외, "매니코어 기반 고성능 컴퓨팅을 지원하는 경량커널 동향", 전자통신동향분석, 32권 4호, 2017, 공공누리 제4유형 [예시2] 심진보 외, "제4차 산업 혁명과 ICT - 제4차 산업 혁명 선도를 위한 IDX 추진 전략", ETRI Insight, 2017, 공공누리 제 4유형
공공누리가 부착되지 않은 자료들을 사용하고자 할 경우에는 담당자와 사전협의한 이후에 이용하여 주시기 바랍니다.