• Title/Summary/Keyword: software radio

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Operating System Architecture and Reconfigure Mechanism for SDR(Software Defined Radio) on Handhold Device (휴대 기기에서의 SDR(Software Defined Radio)을 위한 운영체제 구조와 재구성 기법)

  • Song, In-Jun;Kim, Young-Pil;Yoo, Hyuck
    • Proceedings of the Korean Information Science Society Conference
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    • 2003.10a
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    • pp.355-357
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    • 2003
  • 최근 급속한 발전으로 인해 다양해지고 있는 무선 통신 기술들은 각자의 고유한 주파수, 채널 부호화 기법. 변복조 기법을 쓰는 경우가 많다. 이로 인해, 다양한 무선 통신 기술간의 비호환성 문제가 제기되고 있다. 이러한 문제를 해결하기 위한 기술이 SDR(Software Defined Radio)이다. SDR은 신호 처리(Signal Processing)를 소프트웨어적으로 구현하는 것이다. 이러한 SDR 기술은 하나의 하드웨어를 이용해서 설러 무선 통신 기술들을 이용할 수 있게 한다. 현재 대부분의 SDR의 연구는 재구성 가능한 하드웨어 로직과 코어 프레임워크인 SCA(Software Communication Architecture)로 초점이 맞추어지고 있다 하지만 SDR 시스템의 특성을 고려했을 때, 실시간성(Real-Time)과 유연성(Flexibility), 재구성(Reconfigurability)을 위한 기능을 추가하기 위해 이에 적합한 운영체제의 연구가 필요하다. 본 논문에서는 휴대 기기에서의 SDR 시스템에 대해 간략히 알아보고 이를 위한 운영체제의 요구사항을 설명하여 그에 적합한 운영체제의 구조와 재구성 기법을 설명한다.

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RF 가변 대역 통과 여파기 설계

  • 황희용;김병욱;윤상원
    • Information and Communications Magazine
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    • v.19 no.11
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    • pp.109-122
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    • 2002
  • 최근 Software Defined Radio(혹은 Software Radio) 관련 연구가 국내외에서 활발해지면서 RF부품 및 시스템에 적용하기 위한 연구가 새로운 주제로 부각되고 있다. 본 고에서는 이러한 추세에 맞추어 RF 대역에서 부품 및 시스템의 연구 내용 검토하며, 가장 문제가 된다고 판단되는 대역통과여파기의 설계를 중심으로 논의하고자 한다.

Improving TCP Performance Over Cognitive Radio Networks (인지 무선 환경에서 TCP 성능 향상)

  • Byun, Sang-Seon
    • IEMEK Journal of Embedded Systems and Applications
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    • v.9 no.6
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    • pp.353-360
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    • 2014
  • In cognitive radio networks (CRNs), SU (secondary user)'s transmissions are frequently disrupted by PU (primary user)'s transmission. Therefore SU expereiences consecutive retransmission timeout and its exponential backoff, and subsequently, the TCP of SU does not proceed with the transmission even after the disruption is over or the SU succeeds to hold an idle channel. In order to solve this problem, we propose a cross-layer approach called TCP-Freeze-CR. Moreover we consider a practical scenario where either secondary transmitter (ST) or secondary receiver (SR) detects PU's transmission, which results in the need of spectrum synchronization mechanism. All of our proposals are implemented and verified with a real CRN testbed consisting of 6 software radios called USRP. The experimental results illustrate that standard TCP suffers from significant performance degradation and show that TCP-Freeze-CR greatly mitigates the degradation.

Dynamic BS-initiated idle timer for radio resource management in mobile wireless systems (동적 타이머를 이용한 기지국의 무선 자원 제어론)

  • Yoon, Tai-Ho;Choi, Jin-Young
    • Proceedings of the Korean Information Science Society Conference
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    • 2011.06a
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    • pp.361-364
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    • 2011
  • Nowadays, an explosive increase of mobile devices has triggered a lot of research into radio resource management. Therefore, many studies have been done and still underway to use this limited resource efficiently. However, most of the existing studies focused on efficiency in mac layer. In this paper, I proposed a timer to manage radio resource, which refreshes the timer's values based on the number of connections dynamically. This dynamic timer enables Base Station (BS) to be able to manage available radio resources efficiently and accommodate much more Mobile Stations (MSs). Simulation result showed that BS with dynamic timer could accommodate the MS about 30% more, compared with BS with a static timer in terms of radio resource management. Dynamic timer is not restricted to any specific network standard. So its mechanism is practical and implementable without changing the original standard, which can contribute to service providers by increasing capability that BS can support.

A Study of Quality Evaluation for SDR System Operating Software (SDR 시스템의 운용소프트웨어 품질평가에 관한 연구)

  • Kim, Min-Soo;Lee, Kun-Joon;Ha, Sung-Jae;Cho, Sang-Young
    • Journal of the Korean Institute of Intelligent Systems
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    • v.24 no.6
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    • pp.657-664
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    • 2014
  • In this paper, we described evaluation software that can propose rating scale and evaluate automatically on SDR(Software-Defined Radio) transmitter system. To deduct suitable rating scale, we extracted requirements based on the operating environment, operating application and operating method because SDR operating software is subordinative to the hardware. And we implementation evaluation software to automatically quality evaluation using rating scale draw from the requirements. The implemented evaluation software has automatically evaluation functions using script, can update the evaluation factor and show visual evaluation result. The implemented evaluation software is used to useful the high quality SDR operating software development.

Analysis of Global Trends and Issues of Cognitive Radio (Cognitive Radio 연구의 국내외 동향과 이슈 분석)

  • Moon, Sangook
    • Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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    • 2009.10a
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    • pp.969-972
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    • 2009
  • With the advent of the era of ubiquitous computing, the number of wireless communication devices has been exponentially increasing, which phenomenon requires for the preparation for the upcoming shortage of frequency resource. Recently, in consequence, the concept of Cognitive Radio (CR) was introduced in which the wireless nodes periodically recognize and learn the external conditions of communication including the usage of the frequency spectrum. It is essential to assure sufficient range of frequency to satisfy the users of the increasing wireless network devices. However, since not only the frequency band for wireless communication is finite, but most part of them had already been assigned for the primary users of the wireless network service, it is very difficult to ensure the band of frequency for additional communication service. In this contribution, we analyze and describe the issues of designing and implementation of CR networks.

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A Design and Implementation of Software Defined Radio for Rapid Prototyping of GNSS Receiver

  • Park, Kwi Woo;Yang, Jin-Mo;Park, Chansik
    • Journal of Positioning, Navigation, and Timing
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    • v.7 no.4
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    • pp.189-203
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    • 2018
  • In this paper, a Software Defined Radio (SDR) architecture was designed and implemented for rapid prototyping of GNSS receiver. The proposed SDR can receive various GNSS and direct sequence spread spectrum (DSSS) signals without software modification by expanded input parameters containing information of the desired signal. Input parameters include code information, center frequency, message format, etc. To receive various signal by parameter controlling, a correlator, a data bit extractor and a receiver channel were designed considering the expanded input parameters. In navigation signal processing, pseudorange was measured based on Coordinated Universal Time (UTC) and appropriate navigation message decoder was selected by message format of input parameter so that receiver position can be calculated even if SDR is set up various GNSS combination. To validate the proposed SDR, the software was implemented using C++, CUDA C based on GPU and USRP. Experimentation has confirmed that changing the input parameters allows GPS, GLONASS, and BDS satellite signals to be received. The precision of the position from implemented SDR were measured below 5 m (Circular Error Probability; CEP) for all scenarios. This means that the implemented SDR operated normally. The implemented SDR will be used in a variety of fields by allowing prototyping of various GNSS signal only by changing input parameters.

A Resource Design Methodology and Adapters Implementation for Core Framework for Software Defined Radio

  • Son, Jin-Ho;Tai M. Chung
    • Journal of electromagnetic engineering and science
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    • v.3 no.2
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    • pp.91-98
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    • 2003
  • Software Communication Architecture(SCA) has been made to reduce the development period of new waveform applications by reusing design modules. Software Defined Radio(SDR) forum adopted SCA specification and follows its design concept. However, SCA specification does not describe interfaces and deployments of resources in details, which are software components, and how to implement them as well as how to communicate each other are another missing points in specification. In this paper, we propose a resource design methodology and details of adapter implementation for Core Framework(CF) that is a core set of open interface and services providing an abstraction of the underlying software and hardware layer. We also present SDR prototype system which communicates with resources implemented in different programming languages and processors in legacy environment through our design methodology.

A Novel Parallel Viterbi Decoding Scheme for NoC-Based Software-Defined Radio System

  • Wang, Jian;Li, Yubai;Li, Huan
    • ETRI Journal
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    • v.35 no.5
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    • pp.767-774
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    • 2013
  • In this paper, a novel parallel Viterbi decoding scheme is proposed to decrease the decoding latency and power consumption for the software-defined radio (SDR) system. It implements a divide-and-conquer approach by first dividing a block into a series of subblocks, then performing independent Viterbi decoding for each subsequence, and finally merging the surviving subpaths into the final path. Moreover, a network-on-chip-based SDR platform is used to evaluate the performance of the proposed parallel Viterbi decoding scheme. The experiment results show that our scheme can speed up the Viterbi decoding process without increasing the BER, and it performs better than the current state-of-the-art methods.

Further Specialization of Clustered VLIW Processors: A MAP Decoder for Software Defined Radio

  • Ituero, Pablo;Lopez-Vallejo, Marisa
    • ETRI Journal
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    • v.30 no.1
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    • pp.113-128
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    • 2008
  • Turbo codes are extensively used in current communications standards and have a promising outlook for future generations. The advantages of software defined radio, especially dynamic reconfiguration, make it very attractive in this multi-standard scenario. However, the complex and power consuming implementation of the maximum a posteriori (MAP) algorithm, employed by turbo decoders, sets hurdles to this goal. This work introduces an ASIP architecture for the MAP algorithm, based on a dual-clustered VLIW processor. It displays the good performance of application specific designs along with the versatility of processors, which makes it compliant with leading edge standards. The machine deals with multi-operand instructions in an innovative way, the fetching and assertion of data is serialized and the addressing is automatized and transparent for the programmer. The performance-area trade-off of the proposed architecture achieves a throughput of 8 cycles per symbol with very low power dissipation.

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