1,802 research outputs found

    Solutions for wireless internet connectivity in remote and rural areas

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    Abstract. These days internet connectivity is listed in the basic needs of human habitat. Internet provides inevitable support in getting knowledge, professional and social connectivity, entertainment media, and in running majority of businesses. Human dependency on internet for efficient, proficient and time saving work has increased the demand of internet connectivity worldwide. The global index shows a percentage increase in internet users from 16% to 48% (of the world population) from 2005 to 2019. The users are accessing internet via different media, inclusive of fixed lines and wireless connectivity. In wireless connectivity by 2019, 86% of the world population is using mobile broadband services offered by different telecom operators in different regions. Around 44.7% of the world population lives in rural areas as projected in 2018. Telecom operators are now seeking to cover all urban and rural, segregated, and dense, plateaus and hills, small and big geographical areas for internet connectivity. The majority of challenges faced by operators for deployment of internet connectivity services are in rural areas. Internet users cited in rural areas experience poor coverage and bad quality of service (QoS) in wireless internet access. This thesis covers the rural area internet connectivity challenges, existing deployable solutions against the challenges, and provides example solutions to overcome these challenges, to provide wireless network coverage in rural areas of Finland. Many of the existing wireless communication services are directly deployable or adjustable to the remote or rural areas almost the same way as for the urban areas. The major challenge is the low annual revenue per unit and segregated population densities of rural areas, which increase the return of investment time of network service providers. There are other challenges like ease of assembly, technology, backhaul connectivity, and electricity discussed in the thesis. The possible wireless network solutions deployable for wide area network regions and local area network regions are presented in this thesis. Thesis presents all emerging wireless technologies like small cell base station, super tower, balloon Loon project, power line Airgig project, satellite Viasat service, fixed wireless internet, and signal booster. Two possible network solutions for wireless network coverage in rural areas of Finland are analysed in the thesis. Huawei’s RuralStar small cell base station is presented as the first network solution from the viewpoint of network service provider. Hajakaista network services to individual user are presented as the second network solution from the viewpoint of end user. An addition of outdoor router in Hajakaista network architecture is presented as an additional advantage of outdoor Wi-Fi service together with indoor Wi-Fi. The limitations of the network solutions and future work scope are discussed in the discussion part of the thesis.Langattomia tietoliikenneratkaisuja syrjäalueille. Tiivistelmä. Nykyisin internetyhteys nähdään perustarpeeksi koska se antaa pääsyn tietoon, mahdollistaa ammatilliset ja sosiaaliset yhteydet sekä toimii viihdeväylänä ja tärkeänä osana liiketoimintaa. Tämän vuoksi tarve internetyhteydelle on kasvanut maailmanlaajuisesti. Vuonna 2005 maailman ihmisistä 16 % oli yhteys internettiin ja 2019 48 %. Internetyhteys voidaan saada usealla eri tavalla kuten valokuidulla ja langatonta yhteyttä käyttäen. Vuonna 2019 maailman ihmisistä 86 % käytti langatonta tekniikkaa. Vuonna 2018 44,7 % ihmisistä asui maaseutualueilla. Teleoperaattorit yrittävät kattaa kaikki kaupunki- ja maaseutualueet; eristyneet, tasaiset, kukkulaiset, isot ja pienet maantieteelliset alueet. Suurimmat haasteet ovat maaseudulla, jossa ihmiset kokevat huonoa yhteyspeittoa ja yhteyden laatua. Tämä diplomityö tarkastelee, miten nykyisiä langattomia järjestelmiä voitaisiin käyttää maaseudulla toimivien yhteyksien luomiseksi. Työ esittää kaksi esimerkkiratkaisua Suomen olosuhteisiin. Monet nykyisin kaupungeissa käytettävät ratkaisut ovat suoraan tai lähes suoraan sovellettavissa maaseudulle. Päähaasteet ovat matala vuosittainen yksikkötuotto ja hajallaan olevat alueet, jotka syyt kasvattavat investoinnin kuoletusaikaa. Muita haasteita ovat asennus, teknologia, siirtoyhteydet (tukiasemasta verkkoon) ja sähkön saanti, joita tarkastellaan työssä. Mahdollisia langattomia ratkaisuja ovat laajan alueen ja paikalliset ratkaisut, kuten työssä tuodaan esille. Työ tarkastelee solukkoverkkoja, supertornia, palloprojekti Loonia, sähkölinjoihin pohjautuvaa Airgig-projektia, Viasat-satelliittiratkaisua, kiinteää solukkoyhteyttä ja signaalin passiivista vahvistamista. Työ esittää kaksi ratkaisumallia Suomen olosuhteisiin. Toinen perustuu Huawein RuralStar-kevyttukiasemaan, jolla voi jatkaa operaattorin verkkoa. Toinen ratkaisu on kuluttajalähtöinen ja se perustuu Hajakaista Oy:n ratkaisuun. Siinä lisätään Hajakaista Oy:n perusratkaisun eli talon sisäisen Wi-Fi-verkon rinnalle ulkoinen Wi-Fi-verkko. Ratkaisujen rajoitteita tarkastellaan työn keskusteluosuudessa

    The Impact of Interference on GNSS Receiver Observables – A Running Digital Sum Based Simple Jammer Detector

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    A GNSS-based navigation system relies on externally received information via a space-based Radio Frequency (RF) link. This poses susceptibility to RF Interference (RFI) and may initiate failure states ranging from degraded navigation accuracy to a complete signal loss condition. To guarantee the integrity of the received GNSS signal, the receiver should either be able to function in the presence of RFI without generating misleading information (i.e., offering a navigation solution within an accuracy limit), or the receiver must detect RFI so that some other means could be used as a countermeasure in order to ensure robust and accurate navigation. Therefore, it is of utmost importance to identify an interference occurrence and not to confuse it with other signal conditions, for example, indoor or deep urban canyon, both of which have somewhat similar impact on the navigation performance. Hence, in this paper, the objective is to investigate the effect of interference on different GNSS receiver observables in two different environments: i. an interference scenario with an inexpensive car jammer, and ii. an outdoor-indoor scenario without any intentional interference. The investigated observables include the Automatic Gain Control (AGC) measurements, the digitized IF (Intermediate Frequency) signal levels, the Delay Locked Loop and the Phase Locked Loop discriminator variances, and the Carrier-to-noise density ratio (C/N0) measurements. The behavioral pattern of these receiver observables is perceived in these two different scenarios in order to comprehend which of those observables would be able to separate an interference situation from an indoor scenario, since in both the cases, the resulting positioning accuracy and/or availability are affected somewhat similarly. A new Running Digital Sum (RDS) -based interference detection method is also proposed herein that can be used as an alternate to AGC-based interference detection. It is shown in this paper that it is not at all wise to consider certain receiver observables for interference detection (i.e., C/N0); rather it is beneficial to utilize certain specific observables, such as the RDS of raw digitized signal levels or the AGC-based observables that can uniquely identify a critical malicious interference occurrence

    Mutation determination of rice by using RAPD primers

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    PCR is a powerful tool for the amplification of genetic sequences but sometimes, even though using an established PCR protocol that had been optimized and successful for the amplification of a particular DNA segment, use of that same protocol on a different region can result in a less than desirable outcome. Therefore, an experiment was conducted at Molecular biology laboratory of Malaysian Nuclear Agency during December 2016 to January 2017 used seeds of 6 indica rice cultivars. To conduce RAPD experiments for the rice species it was established the following reaction conditions for the final volume of 20 μl where 0.1 unit of Taq DNA polymerase, 0.4 μl of each dNTP, 2.5 mM MgCl2, 1 μl primer and 2.0 μl of DNA template. From this experiment, it is clear that after mutation the parent MR219 performed some genetic modification and produce genetically different variety namely NMR151, NMR152, ML3, ML10 and ML30. These mutant varieties have two different groups based on their mutation source and it is clear enough from their RAPD profile. Int. J. Agril. Res. Innov. & Tech. 9 (1): 1-7, June, 201

    Influence of anisotropic ion shape, asymmetric valency, and electrolyte concentration on structural and thermodynamic properties of an electric double layer

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    Grand canonical Monte Carlo simulation results are reported for an electric double layer modelled by a planar charged hard wall, anisotropic shape cations, and spherical anions at different electrolyte concentrations and asymmetric valencies. The cations consist of two tangentially tethered hard spheres of the same diameter, dd. One sphere is charged while the other is neutral. Spherical anions are charged hard spheres of diameter dd. The ion valency asymmetry 1:2 and 2:1 is considered, with the ions being immersed in a solvent mimicked by a continuum dielectric medium at standard temperature. The simulations are carried out for the following electrolyte concentrations: 0.1, 1.0 and 2.0 M. Profiles of the electrode-ion, electrode-neutral sphere singlet distributions, the average orientation of dimers, and the mean electrostatic potential are calculated for a given electrode surface charge, σ\sigma, while the contact electrode potential and the differential capacitance are presented for varying electrode charge. With an increasing electrolyte concentration, the shape of differential capacitance curve changes from that with a minimum surrounded by maxima into that of a distorted single maximum. For a 2:1 electrolyte, the maximum is located at a small negative σ\sigma value while for 1:2, at a small positive value.Comment: 10 pages, 6 figure
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