• 디지털산업정보학회논문지
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• 제14권4호
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• pp.93-99
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• 2018

This paper presents an implementation method using NDK (Network Developer's Kit) of GNU (GNU is Not Unix) Radio and Multicore DSP (Digital Signal Processor) to implement LTE (Long Term Evolution) SDR (Software Defined Radio) Platform. In order to satisfy 1.4MHz, 3MHz, 5MHz and 10MHz of the bandwidth supported by LTE, USRP (Universal Software Radio Peripheral) X series which is an RF (Radio Frequency) transceiver of Ettus Research was used. To control this, GNU Radio which is an open source software radio toolkit was used. We also used NDK from TI (Texas Instruments) DSP to transfer data between USRP and DSP. Experimental results show throughput results according to each bandwidth, thus confirming the feasibility of implementing LTE SDR Platform using GNU Radio and NDK of TI DSP.

• 한국정보통신학회논문지
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• 제20권11호
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• pp.2014-2020
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• 2016

일반적으로 스마트 도어락을 이용한 공공 시설물 관리 시스템은 블루투스 무선 통신 구간에서 항상 보안 취약점을 가지게 된다. 특히 인증 절차 과정에서 비밀키와 같은 중요한 정보를 교환할 때는 주로 무선 구간에서 공격자에 노출될 위험이 높다. 그러므로 무선 구간에서 교환되는 정보는 적절하게 암호화되어 전송될 필요가 있다. 지하철 환기구와 같은 공공 시설물 관리 시스템의 보안 취약점을 분석하기 위해서 GNU Radio 플랫폼과 HackRF 장비의 도입을 통해 소프트웨어적 전력분석 공격이 효율적으로 수행 가능함을 확인하였다. 실험장비를 통해 얻어진 무선 패킷은 패킷 타입, CRC, 데이터 길이 및 데이터 등으로 간단하게 디코딩할 수 있으며 이는 보안취약점 개선에 활용될 예정이다.

• Journal of information and communication convergence engineering
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• 제16권1호
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• pp.23-30
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• 2018

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.

• 한국산학기술학회논문지
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• 제9권3호
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• pp.674-680
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• 2008

범용 컴퓨팅 기반 SDR (Software Defined Radio) 시스템은 높은 개발 효율성, 소프트웨어 호환성, 범용 프로세서 사용에 따른 가격대비 성능의 혜택 등의 장점을 갖는다. 본 논문은 인텔 펜티엄 프로세서 및 리눅스로 운용되는 범용 컴퓨팅 플랫폼에서 동작하는 SDR 방식의 무선전화기 겸 워키토키 시스템의 설계 및 구현을 다룬다. 이를 위해 RF 전단부 하드웨어를 개발하여 오픈 소스로 진행 중인 GNU radio 미들웨어와 연동되도록 하였으며 그 위에 변조/복조 소프트웨어 모듈을 개발하였다. 실험 결과, 기존 900 MHz 상용 무선전화기와 호환되며 동시에 FM 워키토키를 지원하는 범용 컴퓨팅 플랫폼 기반 SDR 소프트웨어를 성공적으로 운용할 수 있음을 확인할 수 있었다. 그러나 런타임 소프트웨어 재구성 지원, TCP/IP통신 프로토콜과의 효율적인 연동 등은 향후 개선을 위한 연구가 이루어져야 할 것으로 파악되었다.

• International journal of advanced smart convergence
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• 제7권3호
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• pp.23-36
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• 2018

In wireless communication, efficient spectrum usage is an issue that has been an attractive research area for many technologies. Recently new technologies innovations allow compact radios to transmit with power efficient communication over very long distances. For example, Low-Power Wide Area Networks (LPWANs) are an attractive emerging platform to connect the Internet-of-Things (IoT). Especially, LoRa is one of LPWAN technologies and considered as an infrastructure solution for IoT. End-devices use LoRa protocol across a single wireless hop to communicate to gateway(s) connected to the internet which acts as a bridge and relays message between these LoRa end-devices to a central network server. The use of the (ISM) spectrum sharing for such long-range networking motivates us to implement spectrum sensing testbed for cognitive radio network based on LoRa and GNU radio. In cognitive radio (CR), secondary users (SUs) are able to sense and use this information to opportunistically access the licensed spectrum band in absence of the primary users (PUs). In general, PUs have not been very receptive of the idea of opportunistic spectrum sharing. That is, CR will harmfully interfere with operations of PUs. Subsequently, there is a need for experimenting with different techniques in a real system. In this paper, we implemented spectrum sensing for cognitive radio networks based on LoRa and GNU Radio, and further analyzed corresponding performances of the implemented systems. The implementation is done using Microchip LoRa evolution kits, USRPs, and GNU radio.

• IEIE Transactions on Smart Processing and Computing
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• 제5권2호
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• pp.100-106
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• 2016

Spectrum sensing is an integral part of cognitive radio, which seeks to address the perceived spectrum scarcity that is caused by inefficient utilization of the available spectrum. In this paper, a spectrum sensing system using energy detection for analog TV and FM broadcast transmitters as well as modified Integrated Services Digital Broadcasting Terrestrial (ISDB-T) signals is implemented on a software-defined radio platform using GNU' Not Unix (GNU) radio and the N200 Universal Software Radio Peripheral (USRP). Real-time implementation and experimental tests were conducted in Metro Cebu, a highly urbanized area in the southern part of the Philippines. Extensive tests and measurements were necessary to determine spectrum availability, particularly in the TV band. This is in support of the Philippine government' efforts to provide internet connectivity to rural areas. Experimental results have so far met IEEE 802.22 requirements for energy detection spectrum sensing. The designed system detected signals at -114 dBm within a sensing time of 100 ms. Furthermore, the required $P_d({\geq}90)$ and $P_{fa}({\leq}10)$ of the standard were also achieved with different thresholds for various signal sources representing primary users.

• ETRI Journal
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• 제38권3호
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• pp.455-462
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• 2016

Frequency hopping (FH) is a common characteristic of a wide variety of communication systems. On the other hand, software-defined radio (SDR) is an increasingly utilized technology for implementing modern communication systems. The main challenge when trying to realize an SDR FH system is the frequency tuning time, that is, the higher the hopping rate, the lower the required frequency tuning time. In this paper, significant universal hardware driver tuning options (within GNU Radio software) are investigated to discover the tuning option that gives the minimum frequency tuning time. This paper proposes an improved SDR frequency tuning algorithm for the generation of a target signal (with a given target frequency). The proposed algorithm aims to improve the frequency tuning time without any frequency deviation, thus allowing the realization of modern communication systems with higher FH rates. Moreover, it presents the design and implementation of an original GNU Radio Companion block that utilizes the proposed algorithm. The target SDR platform is that of the Universal Software Radio Peripheral USRP-N210 paired with the RFX2400 daughter board. Our results show that the proposed algorithm achieves higher hopping rates of up to 5,000 hops/second.

• 한국정보통신학회논문지
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• 제26권5호
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• pp.694-702
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• 2022

본 연구에서는 ATSC 기반 무선통신시스템을 비면허대역에서 개인방송시스템으로 활용 가능함을 보였다. 혼/간섭 신호가 존재하는 비면허대역에서 양질의 서비스를 제공하기 위하여 CR 개념을 도입한 채널 적응형 시스템으로 설계하였으며, 폐루프 능동위상배열안테나를 설계하여 연동함으로써 고신뢰성 통신이 가능함을 보였다. USRP기반으로 하는 오픈소스 신호처리 플랫폼인 GNU Radio를 사용하였고 이와 더불어 내부 FPGA에 추가적인 기능을 구현함으로써, 사용자가 원하는 ATSC 기반 개인방송 플랫폼을 쉽고 유연하게 설계하고 수정할 수 있도록 하였다. 또한, 실시간으로 송수신 간 채널의 상태 및 통신 파라미터 등의 정보를 전송하는 리턴 채널과 스펙트럼 검출을 구현하여 통신 주파수 자원을 효율적으로 관리 및 제어할 수 있도록 하였다.