• Title/Summary/Keyword: Radio-based

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A Generalized Markovian Based Framework for Dynamic Spectrum Access in Cognitive Radios

  • Muthumeenakshi, K.;Radha, S.
    • KSII Transactions on Internet and Information Systems (TIIS)
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    • v.8 no.5
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    • pp.1532-1553
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    • 2014
  • Radio spectrum is a precious resource and characterized by fixed allocation policy. However, a large portion of the allocated radio spectrum is underutilized. Conversely, the rapid development of ubiquitous wireless technologies increases the demand for radio spectrum. Cognitive Radio (CR) methodologies have been introduced as a promising approach in detecting the white spaces, allowing the unlicensed users to use the licensed spectrum thus realizing Dynamic Spectrum Access (DSA) in an effective manner. This paper proposes a generalized framework for DSA between the licensed (primary) and unlicensed (secondary) users based on Continuous Time Markov Chain (CTMC) model. We present a spectrum access scheme in the presence of sensing errors based on CTMC which aims to attain optimum spectrum access probabilities for the secondary users. The primary user occupancy is identified by spectrum sensing algorithms and the sensing errors are captured in the form of false alarm and mis-detection. Simulation results show the effectiveness of the proposed spectrum access scheme in terms of the throughput attained by the secondary users, throughput optimization using optimum access probabilities, probability of interference with increasing number of secondary users. The efficacy of the algorithm is analyzed for both imperfect spectrum sensing and perfect spectrum sensing.

Path Loss Characteristics of TETRA-based KTX Train Radio Propagation (TETRA 기반 고속철도 열차무선의 전파 경로손실 특성)

  • Bae, Sung-Ho;Choi, Kyu-Hyoung
    • Journal of the Korea Academia-Industrial cooperation Society
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    • v.14 no.6
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    • pp.2985-2991
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    • 2013
  • Train radio system has been constructed in the second stage of Kyung-bu high speed railway adopting TETRA(Terrestial trunk radio) standard at 851MHz frequency band. The base stations of the train radio system should be located along railway track to ensure seamless communication between train and wayside taking the path loss of train radio propagation into consideration. This paper provides a quantitative analysis of the path loss characteristics based on the measurement results of the train radio propagation along the high speed railway. The free space propagation model and Okumura-Hata model are generally used for base station design, but they predicted 10dB lower or 20dB higher than the measured path loss. Linear regression of the field measured data by applying the log-distance model shows path loss exponent is in the 2.8-3.2 range, which can be used to predict the path loss of the train radio propagation.

Regionalized TSCH Slotframe-Based Aerial Data Collection Using Wake-Up Radio (Wake-Up Radio를 활용한 지역화 TSCH 슬롯프레임 기반 항공 데이터 수집 연구)

  • Kwon, Jung-Hyok;Choi, Hyo Hyun;Kim, Eui-Jik
    • Journal of Internet of Things and Convergence
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    • v.8 no.2
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    • pp.1-6
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    • 2022
  • This paper presents a regionalized time slotted channel hopping (TSCH) slotframe-based aerial data collection using wake-up radio. The proposed scheme aims to minimize the delay and energy consumption when an unmanned aerial vehicle (UAV) collects data from sensor devices in the large-scale service area. To this end, the proposed scheme divides the service area into multiple regions, and determines the TSCH slotframe length for each region according to the number of cells required by sensor devices in each region. Then, it allocates the cells dedicated for data transmission to the TSCH slotframe using the ID of each sensor device. For energy-efficient data collection, the sensor devices use a wake-up radio. Specifically, the sensor devices use a wake-up radio to activate a network interface only in the cells allocated for beacon reception and data transmission. The simulation results showed that the proposed scheme exhibited better performance in terms of delay and energy consumption compared to the existing scheme.

Joint Beamforming and Power Allocation for Multiple Primary Users and Secondary Users in Cognitive MIMO Systems via Game Theory

  • Zhao, Feng;Zhang, Jiayi;Chen, Hongbin
    • KSII Transactions on Internet and Information Systems (TIIS)
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    • v.7 no.6
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    • pp.1379-1397
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    • 2013
  • We consider a system where a licensed radio spectrum is shared by multiple primary users(PUs) and secondary users(SUs). As the spectrum of interest is licensed to primary network, power and channel allocation must be carried out within the cognitive radio network so that no excessive interference is caused to PUs. For this system, we study the joint beamforming and power allocation problem via game theory in this paper. The problem is formulated as a non-cooperative beamforming and power allocation game, subject to the interference constraints of PUs as well as the peak transmission power constraints of SUs. We design a joint beamforming and power allocation algorithm for maximizing the total throughput of SUs, which is implemented by alternating iteration of minimum mean square error based decision feedback beamforming and a best response based iterative power allocation algorithm. Simulation results show that the algorithm has better performance than an existing algorithm and can converge to a locally optimal sum utility.

Study on D2D Relay based Interconnection Network of HAM Radio and Wi-Fi for Securing Communication Performance in Satellite Wireless Package Systems (이동단말용 위성 통신 무선 패키지 시스템을 위한 D2D Relay 기반 HAM Radio와 Wi-Fi Network 결합망의 통신 성능 확보 연구)

  • Hwang, Yu Min;Cha, Jae Sang;Kim, Jin Young
    • Journal of Satellite, Information and Communications
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    • v.10 no.1
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    • pp.12-16
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    • 2015
  • In this paper, we introduce a wireless package system based on the amateur radio HR(HAM Radio) and satellite communication as a novel wireless disaster communication system and have configured a interference scenario receiving interference from adjacent base stations and D2D groups in the disaster network. In such interference scenarios, we propose a frequency re-allocation method to avoid interference and communicate with disaster networks by securing the channel capacity required between D2D terminals. As a result of computer simulation, we can find the proposed method has improved BED performance of a gain of 1.5dB and overall system throughput than conventional methods.

Domestic Radio Waves Propagate Management and Control Systems Investigate the System Status (주요선진국 전파관리제도와 국내 전파관리 제도에 대한 조사)

  • Kim, Sung-Hong;Seok, Gyeong-Hyu
    • The Journal of the Korea institute of electronic communication sciences
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    • v.12 no.1
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    • pp.1-8
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    • 2017
  • There propagate use management paradigm in developed countries is changing as Command & Control ${\Rightarrow}$ Market Based ${\Rightarrow}$ Open Access ${\Rightarrow}$ Manage By Technology & Technical Analysis, that the policy response to environmental changes, such as a variety of new technologies. The emergence of service, the proliferation of propagation users It is to activate the market. However, the basic principles of radio management such that the change of paradigm be used to spread in a range that does not affect the interference, such as the horn is to be observed. Around the world in order to prevent the propagation and utilization Horn interference enacted regulations for managing the radio station, and also discipline.

Cognitive Radio Based Spectrum Sharing: Evaluating Channel Availability via Traffic Pattern Prediction

  • Li, Xiukui;Zekavat, Seyed A. (Reza)
    • Journal of Communications and Networks
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    • v.11 no.2
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    • pp.104-114
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    • 2009
  • In this paper, a technique is proposed that enables secondary users to evaluate channel availability in cognitive radio networks. Here, secondary users estimate the utilization of channels via predicting the traffic pattern of primary user, and select a proper channel for radio transmission. The proposed technique reduces the channel switching rate of secondary users (the rate of switching from one channel to another) and the interference on primary users, while maintaining a reasonable call blocking rate of secondary users.

Biform Game Based Cognitive Radio Scheme for Smart Grid Communications

  • Kim, Sungwook
    • Journal of Communications and Networks
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    • v.14 no.6
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    • pp.614-618
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    • 2012
  • Smart grid is widely considered to be a next generation power grid, which will be integrated with information feedback communications.However, smart grid communication technologies are subject to inefficient spectrum allocation problems. Cognitive radio networks can solve the problemof spectrumscarcity by opening the under-utilized licensed bands to secondary users. In this paper, adaptive cognitive radio spectrum sensing and sharing algorithms are developed for smart grid environments. Simulation results are presented to demonstrate the effectiveness of the proposed scheme in comparison with other existing schemes.