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Suh K.-W.,Kangnam University | Jung H.,Kangnam University | Lee J.-H.,Radio Technology Research Group | Jang J.-S.,Kwangwoon University
2010 IEEE Asia-Pacific Conference on Applied Electromagnetics, APACE 2010 - Proceedings | Year: 2010

We propose the methodology of field strength prediction for a digital television (DTV) receiver by virtue of Rec. ITU-R P.1546. The curves shown in this Rec. represent the point-to area field strength for 1kW effective radiated power in the 30 MHz ∼ 3000 MHz. Some computed results are illustrated here from the formulation of field strength for DTV receiver. It was shown that the error of field strength value for dense urban area (R = 30 m) is in the range of about 6.8 ∼ 11.5 % compared with the Okumura-Hata model under some conditions. In addition comparison of service distance between analog and digital TV receivers has been also illustrated. The presented method provides the predicted values of field strength for TV receiver whether transmission quality can be assured or not, and it can be also used to get the protection ratio or separated distance for frequency sharing in the same or adjacent band. © 2010 IEEE.

Lee D.H.,Seoul National University | Jeon W.S.,Korea University | Jeong D.G.,Radio Technology Research Group | Ko G.,Seoul National University | And 2 more authors.
IEEE International Symposium on Personal, Indoor and Mobile Radio Communications, PIMRC | Year: 2010

Due to the license-exempt nature of the cognitive radio (CR), multiple CR networks may operate (coexist) on the same channel. In this paper, we first discuss some techniques for self-coexistence of CR local and personal area networks, where the self-coexistence means the coexistence of homogeneous CR networks using the same PHY/MAC protocol. Then, we propose a self-coexistence etiquette for the ECMA TC48-TG1 system, which is a CR personal area network specification in standardization. Simulation results show that the proposed etiquette supports effectively the self-coexistence of ECMA TC48-TG1 networks. ©2010 IEEE.

Jeong Y.W.,Seoul National University | Jeon W.S.,Seoul National University | Jeong D.G.,Korea University | Song M.S.,Radio Technology Research Group
IEEE International Symposium on Personal, Indoor and Mobile Radio Communications, PIMRC | Year: 2010

Recently, the IEEE 802 working groups for regional, local, metropolitan, and personal area networks undertake standardization of cognitive radio (CR) networks exploiting TV white spaces. Thus, in the near future, various types of IEEE 802 CR systems may operate on the same TV channel simultaneously. A CR system can coexist more effectively with other CR systems on the same TV channel if it can identifies the types of them. In this paper we propose a system identification scheme for distinguishing the coexisting IEEE 802 CR networks, which exploits the unique features of each system. Simulation results show that the proposed scheme identifies IEEE 802 CR systems accurately and efficiently. ©2010 IEEE.

Kang M.,Radio Technology Research Group | Kim B.,Radio Technology Research Group | Kim K.,Radio Technology Research Group | Byun W.,Radio Technology Research Group
International Conference on Infrared, Millimeter, and Terahertz Waves, IRMMW-THz | Year: 2012

80-100GHz sub-harmonically pumped(SHP) and fourth-harmonic pumped (FHP)mixers are designed for point-to-point(P2P) communications. They are fabricated on a 2-mil 0.1μm GaAs pHEMT process. From measured results, SHP mixer shows conversion loss of 9.5 ∼ 11dB and input P1dB of +2dBm with LO signal of 40 ∼ 44GHz. FHP mixer has conversion loss of 16 ∼ 17dB and input P1dB of -2dBm with LO signal of 20 ∼ 23GHz. © 2012 IEEE.

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