• Title/Summary/Keyword: Radio frequency interference

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Channel Selection Scheme to Improve the Performance of Zigbee Networks over WLAN Interference Environment (무선랜 간섭 환경에서 지그비 네트워크 성능 개선을 위한 채널 선택 기법)

  • Son, Jong-In;Chung, Kwang-Sue
    • The Journal of The Korea Institute of Intelligent Transport Systems
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    • v.11 no.2
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    • pp.102-110
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    • 2012
  • ZigBee networks developed for low power and short range communication are being used as home network solution for ubiquitous computing. However, as smart phones and tablet PCs have been widely used, WLANs which use same frequency with ZigBee networks have been increasingly used. Therefore, radio frequency interference causes many problems. To solve radio frequency interference problem among ZigBee networks and WLANs, many researches focus on designing interference minimization schemes in ZigBee networks. However, existing schemes have problems that have waste of resource for detecting interference, and have unnecessary time to avoid interference. In this paper, we propose an interference minimization scheme to solve radio frequency interference in ZigBee networks. The proposed scheme detects interference using ACK mechanism to reduce waste of resource, and avoids interference using table driven channel hopping scheme which is faster than existed schemes. The performance of proposed interference minimization scheme is evaluated by using OPNET simulator. Through the simulation result, we prove that proposed scheme has faster channel hopping than existing schemes.

The Analysis of Radio Interference between Korea and China/japan using Split-step DMFT Algorithm (Sp1it-step DMFT 알고리즘을 이용한 한국과 중국/일본간 전자파 간섭특성 분석)

  • 정남호;손호경;김봉석;백정기;이형수
    • The Journal of Korean Institute of Electromagnetic Engineering and Science
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    • v.13 no.2
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    • pp.196-208
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    • 2002
  • Since radio interference has occurred in the TRS frequency band in the south coastal area, Korea from 1994, similar interference has been observed in the mobile-cellular frequency band. Measurement showed that the sources of the radio interference are those from the base stations for digital cellular systems in Japan. This because the receiving frequency of the base stations in Korea is same as the transmitting frequency of the base stations in Japan. Since the distance between Korea and Japan is 240 ~ 300 km, we can conclude that the main reason of the interference is ducting. In this paper a ducting channel is modeled by split-step DMFT algorithm, and simulation results for measured index profile far east coast and west sea area are analyzed.

WiFi(RLAN) and a C-Band Weather Radar Interference

  • Moon, Jongbin;Ryu, Chansu
    • Journal of Integrative Natural Science
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    • v.10 no.4
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    • pp.216-224
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    • 2017
  • In the terrain of the Korean peninsula, mountainous and flat lands are complexly distributed in small areas. Therefore, local severe weather develops and disappears in a short time due to the influence of the terrain. Particularly in the case of local severe weather with heavy wind that has the greatest influence on aviation meteorology, the scale is very small, and it occurs and disappears in a short time, so it is impossible to predict with fragmentary data alone. So, we use weather radar to detect and predict local severe weather. However, due to the development of wireless communication services and the rapid increase of wireless devices, radio wave jamming and interference problems occur. In this research, we confirmed through the cases that when the radio interference echo which is one of the non-precipitation echoes that occur during the operation of the weather radar is displayed in the image, its form and shape are shown in a long bar shape, and have a strong dBZ. We also found the cause of the interference through the radio tracking process, and solved through the frequency channel negotiation and AP output minimizing. The more wireless devices increase as information communication technology develops in the future, the more emphasized the problem of radio wave interference will be, and we must make the radio interference eliminated through the development of the radio interference cancellation algorithm.

Analysis of Capacity Decrease Through Calculating Statistically the Amount of Interference From IMT-2000 TDD System to FDD System (IMT-2000 TDD시스템에서 FDD시스템으로의 통계적인 간섭량 계산을 통한 FDD 시스템의 용량 감소 분석)

  • Kim, Sung-Jin;Choi, Sang-Sung;Lee, Hyung-Soo
    • Proceedings of the Korea Electromagnetic Engineering Society Conference
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    • 2003.11a
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    • pp.572-575
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    • 2003
  • There is two System for IMT-2000 Service. one is FDD(Frequency Division Duplex), the other is TDD(Time Division Duplex) system. At the 1920MHz, they have common boundary in IMT-2000 frequency allocation of Korea. In this paper, The amount of Interference From TDD MS(Mobile Station) and BS(Base Station) to FDD BS is Analyzed for Investigation on capacity variation of FDD service by frequency separation. the result and methodology in this paper will be used basically for calculating the guard-band between FDD and TDD service in the future

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Throughput and Delay Optimal Scheduling in Cognitive Radio Networks under Interference Temperature Constraints

  • Gozupek, Didem;Alagoz, Fatih
    • Journal of Communications and Networks
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    • v.11 no.2
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    • pp.148-156
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    • 2009
  • The fixed spectrum assignment policy in today's wireless networks leads to inefficient spectrum usage. Cognitive radio network is a new communication paradigm that enables the unlicensed users to opportunistically use the spatio-temporally unoccupied portions of the spectrum, and hence realizing a dynamic spectrum access (DSA) methodology. Interference temperature model proposed by Federal Communications Commission (FCC) permits the unlicensed users to utilize the licensed frequencies simultaneously with the primary users provided that they adhere to the interference temperature constraints. In this paper, we formulate two NP-hard optimal scheduling methods that meet the interference temperature constraints for cognitive radio networks. The first one maximizes the network throughput, whereas the second one minimizes the scheduling delay. Furthermore, we also propose suboptimal schedulers with linear complexity, referred to as maximum frequency selection (MFS) and probabilistic frequency selection (PFS). We simulate the throughput and delay performance of the optimal as well as the suboptimal schedulers for varying number of cognitive nodes, number of primary neighbors for each cognitive node, and interference temperature limits for the frequencies. We also evaluate the performance of our proposed schedulers under both additive white gaussian noise (AWGN) channels and Gilbert-Elliot fading channels.

Real-time implementation of distributed beamforming for simultaneous wireless information and power transfer in interference channels

  • Hong, Yong-Gi;Hwang, SeongJun;Seo, Jiho;Lee, Jonghyeok;Park, Jaehyun
    • ETRI Journal
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    • v.43 no.3
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    • pp.389-399
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    • 2021
  • In this paper, we propose one-bit feedback-based distributed beamforming (DBF) techniques for simultaneous wireless information and power transfer in interference channels where the information transfer and power transfer networks coexist in the same frequency spectrum band. In a power transfer network, multiple distributed energy transmission nodes transmit their energy signals to a single energy receiving node capable of harvesting wireless radio frequency energy. Here, by considering the Internet-of-Things sensor network, the energy harvesting/information decoding receivers (ERx/IRx) can report their status (which may include the received signal strength, interference, and channel state information) through one-bit feedback channels. To maximize the amount of energy transferred to the ERx and simultaneously minimize the interference to the IRx, we developed a DBF technique based on one-bit feedback from the ERx/IRx without sharing the information among distributed transmit nodes. Finally, the proposed DBF algorithm in the interference channel is verified through the simulations and also implemented in real time by using GNU radio and universal software radio peripheral.

A Study on the measurement of Radio Frequency Interference by the Waves from Noise Source in Japan (일본에서 도래하는 전파간섭의 측정에 관한 연구)

  • Bae, Dae-Hwan;Chung, In-Seong;Bae, Jae-Young;Kim, Dong-Il
    • Journal of the Korean Institute of Navigation
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    • v.25 no.2
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    • pp.119-129
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    • 2001
  • Along with the increase of demand of radio communications and with the rapid progress of communication systems, the radio frequency interference of neighbor nations is a matter of argue. This problem is a delicate matter which must be dealt diplomatically with by having a distinct technical back ground. After the radio interference has been experienced in the Korean TRS service on the south seashore due to the base stations including the Fukuoka station in Japan, the radio interference problem between neighbor nations has become the matter of conflict. For the purpose to solve this problem, we has measured the radio waves that come from Fukuoka in Japan mainly to Pusan in Korea and also collected data in real-time.

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The Efficient Allocation Method of DAB Channels on T-DMB Frequency Band (T-DMB 대역에서 DAB 채널의 효율적인 채널 배치 방안)

  • Kim, Joo-Seok;Kim, Kyung-Seok
    • The Journal of the Institute of Internet, Broadcasting and Communication
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    • v.11 no.6
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    • pp.135-141
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    • 2011
  • Analog medias are converting to digital with the development of the digital communications. The Korean radio broadcasting services yet on analog and the research for the digital radio is progressing. The digital conversion of radio broadcasting has already progressed in foreign countries because of the technical limitation of analog broadcasting(The radio-frequency efficiency is poor). DAB is one of the digital radio mode, it doesn't use on AM/FM band and uses on T-DMB frequency band. So, it has an advantage of being able to broadcast with the existing radio without interference at once. On the other hand, it has the potential to cause interference to existing T-DMB broadcasting. In this paper, we propose an efficient DAB channel allocation method for digital radio on T-DMB frequency band. This paper allocates the DAB channel without interference to existing T-DMB broadcasting and proves the proposed method through simulations for the interference analysis.

Basic Study on Radio-Wave Interference Assessment of Wind Turbines (풍력발전기에 의한 전파간섭 영향평가 기초연구)

  • Kim, Hyun-Goo;Kim, Hyo-Tae
    • 한국신재생에너지학회:학술대회논문집
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    • 2006.11a
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    • pp.305-306
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    • 2006
  • This paper introduces a radio-wave interference assessment of wind turbines that were planned to be installed at Homi-Cape in Pohang region where wind resource has been evaluated worthwhile developing a wind farm. In that area, AM radio station with two antennas and a harbor radar facility are located so that radio-wave coupling is inevitable if the wind farm is designed without considering radio-wave environmental impact. A low-frequency analysis using MoM (Method of Moment) is used to examine interference effect caused by wind turbines and an optimal layout minimizes coupling effect is presented.

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A study on the interference on FM Radio channel from DRM+ signal (DRM+에 의한 FM 라디오 방송채널의 간섭 연구)

  • Lee, Sang-Woon
    • Journal of Satellite, Information and Communications
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    • v.6 no.2
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    • pp.35-40
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    • 2011
  • The purpose of this study is to know about the interference on FM Radio channel from DRM+ signal. In Korea, a data service channel, named DARC is operated by a major FM radio broadcaster which has national wide service area. Therefore, an analysis of the interference on FM radio channel with DARC data channel from DRM+, most recently developed digital radio system. Technical parameters of FM radio with DARC data channel and DRM+ system are considered for this simulation. To maintain without no interference from DRM+, FM radio channel with DARC data channel should have the power level difference over 14.7dB at 150KHz frequency distance.