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Subject: 5G

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Now showing 1 - 4 of 4
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    Article
    Citation - WoS: 9
    Citation - Scopus: 12
    A Simplified Model for Characterizing the Effects of Scattering Objects and Human Body Blocking Indoor Links at 28 Ghz
    (Ieee-inst Electrical Electronics Engineers inc, 2019) Dalveren, Yaser; Alabish, Ahmed H.; Kara, Ali
    This paper presents a simple approach to characterize the effects of scattering objects around indoor links at 28 GHz while the link is fully blocked by a human body. The effects of scattering objects nearby the link were studied by conducting measurements with a metallic reflector and the human body. Here, the basic mechanisms of wave propagation, such as reflection and diffraction, were accounted for each scattering object. To predict the attenuation caused by the metallic reflector, a specular reflection model was employed in reflection modeling. In diffraction modeling, on the other hand, the double knife-edge diffraction (DKED) model was exploited to predict the attenuation by the human body. Simulations were then compared with measurements to evaluate the prediction accuracy of the models. Results indicate that the presented simple models work well for indoor links. Therefore, the results of this paper could be extended to model multiple human bodies near the indoor links of fifth generation (5G) systems.
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    Article
    Citation - WoS: 8
    Citation - Scopus: 9
    A Simple Propagation Model To Characterize the Effects of Multiple Human Bodies Blocking Indoor Short-Range Links at 28 Ghz
    (Mdpi, 2021) Dalveren, Yaser; Karatas, Gokhan; Derawi, Mohammad; Kara, Ali
    This study aims to provide a simple approach to characterize the effects of scattering by human bodies in the vicinity of a short-range indoor link at 28 GHz while the link is fully blocked by another body. In the study, a street canyon propagation characterized by a four-ray model is incorporated to consider the human bodies. For this model, the received signal is assumed to be composed of a direct component that is exposed to shadowing due to a human body blocking the link and a multipath component due to reflections from human bodies around the link. In order to predict the attenuation due to shadowing, the double knife-edge diffraction (DKED) model is employed. Moreover, to predict the attenuation due to multipath, the reflected fields from the human bodies around the link are used. The measurements are compared with the simulations in order to evaluate the prediction accuracy of the model. The acceptable results achieved in this study suggest that this simple model might work correctly for short-range indoor links at millimeter-wave (mmWave) frequencies.
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    Conference Object
    Citation - WoS: 2
    Citation - Scopus: 3
    An Experimental Study on the Influence of Human Movement in Indoor Radio Channel at 28ghz
    (Ieee, 2021) Benzaghta, Mohamed; Coruk, Remziye Busra; Yalcinkaya, Bengisu; Kara, Ali
    Human activities around the communication link in an indoor environment have a significant impact on millimeter-wave (mmWave) communication systems, which are used for the new generation of communication networks (5G). Therefore, it is essential to evaluate short range indoor links from the link blockage point of view. This paper presents the propagation measurements in the presence of human activity, for a short range indoor office environment communication link at 28 GHz. During the experimental measurements, the human activity of three and six persons were observed for three different antenna height combinations. The human blockage (shadowing effect) is characterized in terms of the shadowing event duration, temporal fading, as well as overall attenuation. The results reported by this experimental study is believed to be vital in designing future mmWave communication systems that can overcome the deep fades caused by human blockage in short indoor communication links. Yet, this paper constitutes a part of an ongoing research study, further detailed results will be foreseen to present the precise effect of human movements around the propagation link at 28GHz.
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    Master Thesis
    28 Ghz'de Çoklu İnsan Vücudu Gölgelemesinin Ölçülmesi ve Modellenmesi
    (2020) Karataş, Gökhan; Kara, Ali
    Bu tez, iç mekân bağlantısı yakınlarında bulunan saçılmış insan vücutlarının etkilerini karakterize etmek amacıyla basitleştirilmiş insan vücudu modellerini ve onların ölçüm sonuçlarıyla kıyaslamasını sunmaktadır. Çalışmalar; insan vücudu tamamen verici ile alıcı arasındaki bağlantıyı engellerken gerçekleştirilmiştir. Ayrıca, ölçümler kablosuz beşinci nesil (5G) sistemler için büyük öneme sahip olan 28 GHz'de yapılmıştır. Ek olarak, insan vücudu modelleme ve dalga yayılım mekanizmalarının teorik arka planı ile çalışmaları kavramak için gerekli diğer kavramlardan kısaca bahsedilmiştir. Saçılmış halde bulunan insan etkileri, çift bıçak kenarı kırınımı (DKED) ve ışın izleme yoluyla geometrik kırınım teorisi (GTD) gibi modeller kullanılarak benzetimler yapılmıştır. Benzetimler esnasında, modellerde yansıma ve kırınım gibi temel dalga yayılma mekanizmalarından faydalanılmıştır. Benzetimler; bağlantı tamamıyla insan tarafından engellenmiş durumda iken saçılmış olarak bulunan bir ve iki insan vücudu senaryoları için ayrı ayrı gerçekleştirilmiştir. Ayrıca, bu benzetimler ilgili laboratuvar ölçümleri ile karşılaştırılmış ve ümit verici sonuçlar elde edilmiştir. Basitleştirilmiş kırınım modellerinin ölçümlerle uyum içinde olduğu görülmüştür. Bu modellerin milimetre dalgaları (mmWave) için kablosuz kanal tasarlarken faydalı olacağı düşünülmektedir. Diğer yandan, milimetre dalga bantlarında yakın gelecekte yapılacak tahsisler için bu tez çerçevesinde yeni çalışmalar geliştirilebilir. Ayrıca, basitleştirilmiş modeller, çoklu insan vücudunun farklı yerleşimlerdeki etkilerini karakterize etmek için genişletilebilir.