• Title, Summary, Keyword: cognitive radio

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An Energy-efficient MAC Protocol in Cognitive Radio Environment (Cognitive Radio 환경을 고려한 에너지 효율적인 MAC 프로토콜)

  • Kim, Byung-Boo;Rhee, Seung-Hyong
    • The Journal of The Korea Institute of Intelligent Transport Systems
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    • v.7 no.2
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    • pp.81-91
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    • 2008
  • In mobile wireless communications, there is a new approach that uses the lacking spectrum efficiently. A cognitive radio is a device that can changes its transmitter parameters based on interaction with the environment in which it operates. At present, the wireless communication standard for wireless device contains power-saving modes or energy efficient mechanisms which cuts off the power of transmitter and receiver for power-saving. However, in cognitive radio environment, every device has the Quiet Period for searching channel and existing energy-saving method is not appropriate to be adjust to cognitive radio environment. In this paper, we propose an energy-efficient MAC protocol of mobile device in cognitive radio environment and prove the improvement of proposed method.

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Smart Dynamic Pricing in Cognitive Radio Systems

  • Vo, Dat
    • Journal of the Korea Industrial Information Systems Research
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    • v.17 no.2
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    • pp.11-18
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    • 2012
  • Smart Dynamic Pricing has been introduced to address the under-utilised network resources problem in mobile telecommunications systems. In this paper, we investigate the applicability of Smart Dynamic Pricing and its signalling models into Cognitive Radio Systems. Cognitive Radio System is defined as one in which cognitive radios are employed to access shared spectrum and/or dynamically allocated spectrum. Network elements, protocols, traffic and control channels, and system architecture are proposed for the implementation of Smart Dynamic Pricing in Cognitive Radio System. It is found that Smart Dynamic Pricing and its signalling models can be applied to Cognitive Radio Systems.

Cognitive Radio Using ITMA for MB-OFDM UWB System of Korea (무선 인지 기술(Cognitive Radio using ITMA)을 이용한 국내 환경에 적합한 MB-OFDM UWB 시스템)

  • Kim, Tae-Hun;Kim, Dong-Hee;Jang, Hong-Mo;Nam, Sang-Kyun;Kwak, Kyung-Sup
    • The Journal of Korean Institute of Communications and Information Sciences
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    • v.32 no.11A
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    • pp.1096-1105
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    • 2007
  • In this paper, we propose a solution on interference problem of MB-OFDM UWB system using cognitive radio. We use interference temperature model of cognitive radio that has proposed by FCC for estimating interference signal. Calculating channel capacity of MB-OFDM UWB system with interference temperature, we suggest how to solve interference problem. We have used genetic algorithm in cognitive engine's calculation process. The proposed MB-OFDM UWB System with cognitive radio shows very efficient in solving interference problem.

인지 무선 통신망을 위한 인지 알고리즘 및 엔진

  • Song Myeong-Seon;Reed Jeffrey H.;Kim Chang-Ju
    • The Proceeding of the Korean Institute of Electromagnetic Engineering and Science
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    • v.17 no.2
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    • pp.19-27
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    • 2006
  • Technologies to utilize the limited frequency resource more efficiently in spatial and temporal are accelerated. In this paper cognitive algorithms as brain of cognitive radio, kind and characteristics of databases which are necessary parts for algorithm were reviewed and summarized. And an example of cognitive engine on which database and algorithm are executed was described also. Because the current status of development of technologies relating to cognitive radio is at the initial stage, the best database, algorithm and engine for a cognitive radio were not suggested, but the direction of development and factors to be considered during development of relating technologies were explained.

An Adaptive Resource Allocation Scheme in Cognitive Radio Network Assisted Satellite (무선 인지 네트워크에서 위성을 이용한 적응적인 자원 할당 기법)

  • Lee, Seon-Yeong;Sohn, Sung-Hwan;Jang, Sung-Jin;Kim, Jae-Moung
    • Journal of Satellite, Information and Communications
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    • v.4 no.2
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    • pp.5-11
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    • 2009
  • In this paper, we propose our design of adaptive resource allocation in the cognitive radio network assisted by satellite to improve the performance of Cognitive Radio user. Most of today’s telecommunication network operates in a fixed, licensed frequency band using a specific spectrum access network. However, the spectrum is not always used all the time, all the band. It causes the inefficiency in the spectrum usage. Thus, cognitive radio network is proposed to solve these spectrum inefficiency problems. The cognitive radio users (secondary users) are coexistent with primary users (PUs) who are licensed. That cognitive radio network is considered as lower priority comparing with primary user. So, the operation of the cognitive radio network is limited to interference constraints. Especially, when the number of secondary users increases, CCI among SUs will increase as well as interference to PU. That motivates our objective to improve the performance even if cognitive radio users increase. To solve this problem, we suggest an adaptive resource allocation scheme to improve the performance of cognitive radio network assisted by satellite. Through this algorithm, we can improve the cognitive radio network performance. And the simulation results confirm the effectiveness of our proposed algorithm.

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Protection of Digital TV from Cognitive Radio Interference

  • Yoon, Young-Keun;Hong, Heon-Jin;Choi, Ik-Guen
    • ETRI Journal
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    • v.29 no.3
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    • pp.393-395
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    • 2007
  • Analytic modeling and computational simulation for the protection of DTV from cognitive radio interference are performed. Protection is achieved by using the protection ratio, which is derived through system modeling and its analysis. On the frequency coordination between digital TV and cognitive radio, an analysis in a co-channel environment, in a rural area in Korea, is performed.

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Chirp-Based Cognitive Ultra-wideband Radio

  • Shen, Hanbing;Zhang, Weihua;Kwak, Kyung-Sup
    • ETRI Journal
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    • v.29 no.5
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    • pp.676-678
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    • 2007
  • In this letter, we propose a cognitive ultra-wideband radio scheme which is based on a modified chirp waveform. Therefore, it requires only time domain processing in the cognitive radio systems and reduces system complexity and power consumption.

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Design Issues of Spectrum Sensing in Cognitive Radio Networks

  • Kang, Bub-Joo
    • Journal of information and communication convergence engineering
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    • v.9 no.2
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    • pp.166-171
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    • 2011
  • This paper investigates the design issues of spectrum sensing in the cognitive radio (CR) networks of opportunistic unlicensed spectrum access. The cognitive radios can perform a communication using the incumbent user spectrum band without the interference caused by the cognitive radio users. In this case, the cognitive radios must know the real-time radio environments of the incumbent user spectrum band using the spectrum sensing, beacon signal, and geo-location database access. Then in this paper, we are going to provide spectrum sensing issues which include the sensing techniques, the regulatory requirements, the analysis of DTV detection threshold, and main considerations associated with the spectrum sensing design in cognitive radio systems. Also, this paper introduces design trade-offs in order to optimize the sensing parameters such as sensing time and sensing complexity.

Cognitive User's Quality of Service Enhancement by using Spectrum Hole Grouping in Cellular Cognitive Radio Networks (셀룰러 인지 라디오 망에서 스펙트럼 홀 그룹핑에 의한 인지 사용자의 서비스 품질향상)

  • Lee, Jin-yi
    • The Journal of Advanced Navigation Technology
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    • v.23 no.4
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    • pp.322-327
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    • 2019
  • In this paper, we propose first a scheme of grouping spectrum holes that are created in the multiple channels of primary users, and then by using the scheme we enhance quality of service (QoS) of wideband cognitive radio users in cellular cognitive radio networks. In our scheme, spectrum holes created in each primary channel are predicted by Wiener prediction process, and then the predicted spectrum holes happened in the same time are grouped into a group. The wideband cognitive radio users explore the group of spectrum holes to improve their QoS. Simulation results show that their handoff calls dropping rate and initial calls blocking rate are significantly reduced in our scheme, compared to those in the single primary channel.

Efficient DFT/DCT Computation for OFDM in Cognitive Radio System (Cognitive Radio 시스템의 OFDM을 위한 효율적 DCT/DFT 계산에 관한 연구)

  • Chen, Zhu;Kim, Jeong-Ki;Yan, Yi-Er;Lee, Moon-Ho
    • Journal of the Institute of Electronics Engineers of Korea TC
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    • v.45 no.2
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    • pp.97-102
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    • 2008
  • In this paper, we address the OFDM based on DFT or DCT in Cognitive Radio system. An adaptive OFDM based on DFT or DCT in Cognitive Radio system has the capacity to nullify individual carriers to avoid interference to the licensed users. Therefore, there could be a considerably large number of zero-valued inputs/outputs for the IDFT/DFT or IDCT/DCT on the OFDM transceiver. Hence, the standard methods of DFT and DCT are no longer efficient due to the wasted operations on zero. Based on this observation, we present a transform decomposition on two dimensional(2-D) systolic array for IDFT/DFT and IDCT/DCT, this algorithm can achieve an efficient computation for OFDM in Cognitive Radio system