Cognitive Radio 환경을 고려한 에너지 효율적인 MAC 프로토콜

김병부,이승형 한국ITS학회 2008 한국ITS학회논문지 Vol.7 No.2

현재 무선 환경통신에서 점차 고갈되어가는 주파수를 효율적으로 사용하기 위해서 새로운 접근 방법이 개발되었다. Cognitive Radio는 디바이스가 동작하는 환경의 정보에 근거하여 자신의 송수신 방법을 바꿀 수 있는 장비를 말한다. 현재 무선 모바일 디바이스를 대상으로 하는 무선통신표준들은 절전모드에 대해서 다루고 있으며, 대부분 전력절감을 위하여 데이터 송신과 수신에 대한 전원을 차단하는 방법을 이용한다. 하지만 Cognitive Radio 환경에서는 모든 디바이스들이 채널을 검색하기 위해서 Quiet Period를 두고 있으며, 기존의 에너지 절감 방법으로는 Cognitive Radio 환경에 응용하기에는 적합하지 않다. 본 논문에서는 Cognitive Radio 환경에서 무선 모바일 디바이스를 위한 에너지 효율적인 MAC 프로토콜을 제안하고, 시뮬레이션을 통하여 일반적으로 사용되는 에너지관리 방법과 제안한 방법을 비교하여 성능이 향상되었음을 확인한다. 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.

Biomedical Signal Transmission using OFDM-based Cognitive Radio for Wireless Healthcare Applications

S. Mohandass,G. Umamaheswari 한국산학기술학회 2014 SmartCR Vol.4 No.3

This paper describes an efficient design and implementation of orthogonal frequency division multiplexing-based Cognitive Radio to achieve the reliable transmission and reception of biomedical signals over a wireless channel. This concept can be used in wireless healthcare applications where medical information can be transferred through wireless networks for remote medical procedures or examinations. The main purpose of choosing Cognitive Radio is to efficiently utilize the available spectrum. As Cognitive Radio employs smart wireless devices with awareness, sensing, learning, and adaptation capabilities, it proves to be the best solution to solve the spectrum scarcity problem. Frequency bands that are not being used by the primary (licensed) users are utilized by Cognitive Radio users. The requirements of Cognitive Radios can be fulfilled largely by employing the orthogonal frequency division multiplexing technique. Using this technique, signals can easily be adapted to channel conditions and capacity requirements, which make it suitable for Cognitive Radio applications. The radio frequency spectrum utilization can be enhanced, and interference to other users can be minimized largely using orthogonal frequency division multiplexing-based Cognitive Radio. In this paper, we investigate the opportunistic access of the white space spectrum for healthcare applications. We propose a framework for the remote monitoring and analysis of patient health based on Cognitive Radio.

무선 인지 셀룰러 망에서 자원예측에 의한 가드채널 할당기법의 성능개선

이진이 ( Jin Yi Lee ) 한국항행학회 2012 韓國航行學會論文誌 Vol.16 No.5

본 논문에서는 셀룰러 기반 무선 인지망에서 핸드오프 호를 위한 가드채널할당기법(guard channel scheme)의 자원이용률의 저하를 개선하기 위해 무선인지 기술을 사용하여 자원 이용률을 향상시키면서, 무선 인지망의 부 사용자(cognitive radio user) 손실률을 줄이는 방법을 제안한다. 제안한 방법에서는 핸드오프 호의 전용채널(guard channel)을 부 사용자가 이용하도록 하고, MMOSPRED(Multi-Media One Step Prediction)기법으로 핸드오프 호의 발생을 예측한 다음, 핸드오프 호가 발생하면 핸드오프 호의 전용채널을 넘겨주고, 부 사용자는 예약된 자원으로 스펙트럼 핸드오프를 하여 서비스를 완료 하도록 한다. 시뮬레이션을 통하여, 제안한 기법의 자원 이용률과 부 사용자의 손실률에 대한 성능이 기존의 가드채널 할당기법과 모바일의 이동성을 예측하지 않은 채널할당기법 보다 우수함을 보인다. In this paper, we propose a scheme for improving not only the utilization of frequency bands in the guard channel scheme but also the dropping rate of cognitive radio user in the wireless cognitive radio-based cellular network. The proposed scheme enables cognitive radio users to utilize the guard channel for servicing only handoff calls in normal times, but cognitive radio users must vacate the frequency channel when handoff call appearing. At this time our scheme ensures their seamless services for cognitive radio users, by predicting handoff call`s appearance by MMOSPRED (Multi-Media One Step Prediction) method and then reserving the demanded channels for spectrum handoff calls. Our simulations show that our scheme performs better than other schemes; GCS(Guard Channel Scheme) and a scheme without prediction in terms of cognitive users call`s dropping rate and resource utilization efficiency.

펄스 성형을 통한 TH-UWB 시스템 구현과 간섭 회피 제안

장홍모,김태훈,김동희,박호환,곽경섭 한국ITS학회 2007 한국ITS학회논문지 Vol.6 No.3

본 논문은 국내 UWB 스펙트럼 환경에 적합하도록 펄스 성형을 통해 TH-UWB 시스템의 개념을 확장한 TH-Multiband-UWB 시스템을 구현하는 것을 그 목표로 한다. 이러한 펄스 성형을 위하여 Multi-Carrrier 형태의 전송 펄스를 제안하며, 간섭 주파수 검출을 위해 무선 인지 기술(Cognitive Radio)을 사용했다. 무선 인지 기술의 핵심이 되는 Cognitive Engine의 연산 알고리즘으로는 유전 알고리즘을 이용했다. 또한 성형된 펄스와 무선 인지 기술을 적용한 TH-UWB시스템이 동일 UWB 시스템을 비롯한 타 통신 시스템과의 간섭 상황을 해결하는 방법을 제시하였다. 이를 통해 본 논문은 무선 인지 엔진이 간섭 주파수를 찾아내는 방법을 알아보았고, 펄스 성형을 적용한 TH-UWB 시스템이 문제가 되는 간섭 상황을 해결하는데 뛰어난 성능이 있음을 확인하였다. In this paper, we propose a TH-Multiband-UWB system through pulse shaping to fit in domestic UWB spectrum regulation. We propose the transmission pulse of Multi-Carrier type for pulse shaping and use Cognitive Radio to detect interfering frequency. We use Genetic Algorithm in Cognitive Radio's calculation propose and propose solution of interference problem between TH-UWB using Cognitive Radio and typical MB-OFDM UWB system or other communication systems. In this paper, we explain how Cognitive Engine detects the interfering frequency. The technique of TH-Multiband-UWB system using Cognitive Radio shows a good performance in interference condition.

HMM-based Adaptive Frequency-Hopping Cognitive Radio System to Reduce Interference Time and to Improve Throughput

( Sung Hwan Sohn ),( Sung Jeen Jang ),( Jae Moung Kim ) 한국인터넷정보학회 2010 KSII Transactions on Internet and Information Syst Vol.4 No.4

Cognitive Radio is an advanced enabling technology for the efficient utilization of vacant spectrum due to its ability to sense the spectrum environment. It is important to determine accurate spectrum utilization of the primary system in a cognitive radio environment. In order to define the spectrum utilization state, many CR systems use what is known as the quiet period (QP) method. However, even when using a QP, interference can occur. This causes reduced system throughput and contrary to the basic condition of cognitive radio. In order to reduce the interference time, a frequency-hopping algorithm is proposed here. Additionally, to complement the loss of throughput in the FH, a HMM-based channel prediction algorithm and a channel allocation algorithm is proposed. Simulations were conducted while varying several parameters. The findings show that the proposed algorithm outperforms conventional channel allocation algorithms.

Implementation of Spectrum-Sensing for Cognitive Radio Using USRP with GNU Radio and a Cloud Server

Thien, Huynh Thanh,Tendeng, Rene,Vu-Van, Hiep,Koo, Insoo The Korea Institute of Information and Commucation 2018 Journal of information and communication convergen Vol.16 No.1

In cognitive radio (CR), spectrum sensing is an essential function since secondary users (SUs) must determine whether the primary user (PU) is utilizing the channel or not, and furthermore, SUs opportunistically access the licensed channel when the PU is absent. In this paper, spectrum sensing is implemented by energy detection, and a software-defined radio testbed is built to evaluate sensing performance by energy detection in a real environment. In particular, the testbed was built based on the GNU's Not Unix (GNU) Radio software platform and Universal Software Radio Peripheral National Instruments 2900 devices. More specifically, a new block of energy detection is developed by using an out-of-tree module from GNU Radio. To successfully integrate CR into the cloud computing paradigm, we also implement cloud computing-based spectrum sensing by utilizing a cloud server with ThingSpeak, such that we can store, process, and share the sensing information more efficiently in a centralized way in the cloud server.

A Credibility-based Defense SSDF Attacks Scheme for the Expulsion of Malicious Users in Cognitive Radio

Hong Du,Shuang Fu,Hongna Chu 보안공학연구지원센터 2015 International Journal of Hybrid Information Techno Vol.8 No.9

Cognitive radio (CR) can improve the utilization of the spectrum by making use of licensed spectrum in an opportunistic manner. However, the security aspects of cognitive radio networks have garnered little attention. In this paper, we identify a threat to cognitive radio networks, which we call the spectrum sensing data falsification (SSDF) attack. SSDF attack can hugely degrade the achievable detection accuracy. To counter this threat, we proposed a new method to confront the SSDF attacks by excluding malicious users is cognitive radio. In detail, the proposed scheme defense the SSDF attacks by calculating and updating the credit value of the Secondary Users (SUs), malicious users are excluded to avoid the attacks affect in cooperative spectrum sensing. Simulations results show that both the detection probability and the false alarm probability are significantly improved compared to the case when all users are by default trusted to be normal users.

A Directional Cognitive-Radio-Aware MAC Protocol for Cognitive Radio Sensor Networks

Han Su,Sangman Moh 보안공학연구지원센터 2015 International Journal of Smart Home Vol.9 No.4

Recently, cognitive radio (CR) technology is broadly applied even to sensor networks. Cognitive radio sensor networks (CRSNs) have been studied and, apparently, sensor nodes equipped with directional antennas achieve higher energy efficiency. This paper proposes a medium access control (MAC) protocol named directional CR-aware MAC (DC-MAC) for CRSNs. To the best of the authors’ knowledge, this is the first work to propose a MAC protocol for CRSNs with directional antennas. The simulation study shows that DC-MAC is more energy efficient than the conventional protocol by 50%–60% for the RMF TR 1001 transceiver and by 20%–50% for the Bluetooth transceiver.

Performance Analysis of Amplify and Forward (AF)-based Cooperative Spectrum Sensing in Cognitive Radio Networks

Khan, Muhammad Sajjad,Koo, Insoo The Korea Institute of Information and Commucation 2013 Journal of information and communication convergen Vol.11 No.4

Cognitive radio has been recently considered a promising technology to improve spectrum utilization by enabling secondary access to licensed bands that are not used by primary users temporarily or spatially. A prerequisite to this secondary access is the lack of interference to the primary system. This requirement makes spectrum sensing a key process for cognitive radio. In this study, we consider amplify and forward (AF)-based cooperative spectrum sensing for cognitive radio networks where multiple relay nodes are utilized to amplify and forward the primary user signal for better spectrum sensing, and maximum ratio combining is used for fusion detection by a cognitive coordinator. Further, the detection probability and the bit error rate of AF-based cooperative spectrum sensing are analyzed in fading multiple cognitive relay channels. The simulation results show that the AF-based cooperative spectrum sensing scheme outperforms the conventional scheme.

Energy-Efficient, Learning-Inspired Channel Decision and Access Technique for Cognitive Radio-based Wireless Sensor Networks

Joshua Abolarinwa,Nurul Mu’azzah Abdul Latiff,Sharifah Kamilah Syed Yusof,Norsheila Fisal 보안공학연구지원센터 2015 International Journal of Multimedia and Ubiquitous Vol.10 No.2

Cognitive radio-based wireless sensor network is the next-generation sensor network paradigm. Important to this emerging sensor network is the need to reduce energy consumption, paving way for ‘green’ communication among sensor nodes. Therefore, in this paper, we have proposed an energy-efficient, learning-inspired, adaptive and dynamic channel decision and access technique for cognitive radio-based wireless sensor networks. Using intelligent learning technique based on the previous experience, the cognitive radio-based wireless sensor network agent decides which available channel to access based on the energy-efficiency achievable by transmitting using the channel. From simulation results, we found that as the channel packet availability increases, the energy-efficiency of the channel increase. This lends credence to the fact that the proposed learning-inspired algorithm is significantly energy-efficient for cognitive radio-based wireless sensor networks.