1,108 research outputs found

    Performance Analysis of the Cognitive Radio Network with Opportunistic Spectrum Access

    Get PDF
    Efficient access to the spectral resources becomes a challenge for future military wireless communication systems. It requires spectral situation awareness, knowledge of current regulations, local policies and hardware platform limitations. It can be achieved by cognitive radios, realizing cognitive cycle, consisting typically of continuous observation, orientation, reasoning and decision making. All these elements must be realized in parallel and shouldn't interfere with each other. Even more difficult issue is related with cooperation between different nodes, especially in wireless domain, in harsh propagation conditions. Unpredictable phenomena create hard conditions for all deterministic behavior models, and their reproduction is a key element for efficient operation of the network. Very popular computer simulations are always simplified, and real time implementation gives an opportunity to make the next step in system elaboration. This paper presents a real-time demonstrator of cognitive radio network. It can work both in wired mode, using radio channel emulator and in mobile mode, to verify influence of real conditions on proposed cognitive solutions and assess their effectiveness

    Design, Analysis, Implementation and Evaluation of Real-time Opportunistic Spectrum Access in Cloud-based Cognitive Radio Networks

    Get PDF
    Opportunistic spectrum access in cognitive radio network is proposed for remediation of spectrum under-utilization caused by exclusive licensing for service providers that are intermittently utilizing spectrum at any given geolocation and time. The unlicensed secondary users (SUs) rely on opportunistic spectrum access to maximize spectrum utilization by sensing/identifying the idle bands without causing harmful interference to licensed primary users (PUs). In this thesis, Real-time Opportunistic Spectrum Access in Cloud-based Cognitive Radio Networks (ROAR) architecture is presented where cloud computing is used for processing and storage of idle channels. Software-defined radios (SDRs) are used as SUs and PUs that identify, report, analyze and utilize the available idle channels. The SUs in ROAR architecture query the spectrum geolocation database for idle channels and use them opportunistically. The testbed for ROAR architecture is designed, analyzed, implemented and evaluated for efficient and plausible opportunistic communication between SUs

    Combination of a geolocation database access with infrastructure sensing in TV bands

    Get PDF
    This paper describes the implementation and the technical specifications of a geolocation database assisted by a spectrum-monitoring outdoor network. The geolocation database is populated according to Electronic Communications Committee (ECC) report 186 methodology. The application programming interface (API) between the sensor network and the geolocation database implements an effective and secure connection to successfully gather sensing data and sends it to the geolocation database for post-processing. On the other hand, the testbed allows authorized TV white space devices to gain access to the services of the geolocation database, according to a draft implementation of Internet Engineering Task Force (IETF) Protocol to Access White Space (PAWS) Two experimental methodologies are available with the testbed: one focused on coexistence studies with commercial wireless microphones, when the testbed is used for sensing only, and another for demonstration purposes, when the testbed is also used to emulate wireless microphone signals. Overall, this hybrid approach is a promising solution for the effective use of TV white spaces and for the coexistence with digital TV broadcast signals, or dynamic incumbent systems, such as unregistered wireless microphones

    Application-aware Cognitive Multi-hop Wireless Networking Testbed and Experiments

    Get PDF
    In this thesis, we present a new architecture for application-aware cognitive multihop wireless networks (AC-MWN) with testbed implementations and experiments. Cognitive radio is a technique to adaptively use the spectrum so that the resource can be used more efficiently in a low cost way. Multihop wireless networks can be deployed quickly and flexibly without a fixed infrastructure. In presented new architecture, we study backbone routing schemes with network cognition, routing scheme with network coding and spectrum adaptation. A testbed is implemented to test the schemes for AC-MWN. In addition to basic measurements, we implement a video streaming application based on the AC-MWN architecture using cognitive radios. The Testbed consists of three cognitive radios and three Linux laptops equipped with GNU Radio and GStreamer, open source software development toolkit and multimedia framework respectively. Resulting experiments include a range from basic half duplex data to full duplex voice communications and audio/video streaming with spectrum sensing. This testbed is a foundation for a scalable multipurpose testbed that can be used to test such networks as AC-MWN, adhoc, MANET, VANET, and wireless sensor networks. Experiment results demonstrate that the AC-MWN is applicable and valuable for future low-cost and flexible communication networks. Adviser: Yi Qia

    Scalable Cognitive Radio Network Testbed in Real Time

    Get PDF
    Modern society places an increasingly high demand on data transmission. Much of that data transmission takes place through communication over the frequency spectrum. The channels on the spectrum are limited resources. Researchers realize that at certain times of day some channels are overloaded, while others are not being fully utilized. A spectrum management system may be beneficial to remedy this efficiency issue. One of the proposed systems, Cognitive Radio Network (CRN), has progressed over the years thanks to studies on a wide range of subjects, including geolocation, data throughput rate, and channel handoff selection algorithm, which provide fundamental support for the spectrum management system. To move CRN technology forward, in this thesis we propose a physical, scalable testbed for some of the extant CRN methodologies. This testbed integrates IEEE standards, FCC guidelines, and other TV band regulations to emulate CRN in real time. With careful component selections, we include sufficient operational functionalities in the system, while at the same time making sure it remains affordable. We evaluate the technical feasibility of the testbed by studying several simple CRN logics. When comparing a system with a selection table implemented to those with naive selection methods, there is more than a 60 percent improvement in the overall performance

    On the Road to 6G: Visions, Requirements, Key Technologies and Testbeds

    Get PDF
    Fifth generation (5G) mobile communication systems have entered the stage of commercial development, providing users with new services and improved user experiences as well as offering a host of novel opportunities to various industries. However, 5G still faces many challenges. To address these challenges, international industrial, academic, and standards organizations have commenced research on sixth generation (6G) wireless communication systems. A series of white papers and survey papers have been published, which aim to define 6G in terms of requirements, application scenarios, key technologies, etc. Although ITU-R has been working on the 6G vision and it is expected to reach a consensus on what 6G will be by mid-2023, the related global discussions are still wide open and the existing literature has identified numerous open issues. This paper first provides a comprehensive portrayal of the 6G vision, technical requirements, and application scenarios, covering the current common understanding of 6G. Then, a critical appraisal of the 6G network architecture and key technologies is presented. Furthermore, existing testbeds and advanced 6G verification platforms are detailed for the first time. In addition, future research directions and open challenges are identified for stimulating the on-going global debate. Finally, lessons learned to date concerning 6G networks are discussed
    corecore