Examining the Effects of Human Bodies Blocking Indoor Links at 28 GHz with a Perfectly Conducting Cylinder Model

Year 2020, Volume: 8 Issue: 1, 1118 - 1127, 31.01.2020

Yaser Dalveren Ali Kara

https://doi.org/10.29130/dubited.605614

Abstract

In the literature, due to its mathematically tractable nature, Double Knife-Edge Diffraction (DKED) model is often used to predict the loss caused by human body blockage in short-range indoor links. However, the rectangular screen used to simulate the human body in the model may insufficient to represent the physics of human body. This adversely affects the prediction accuracy of the model especially in the presence of multiple human blockage events. On the other hand, perfectly conducting cylinder model based on Geometrical Theory of Diffraction (GTD) is another well-known model used in the literature. Yet, the prediction accuracy of this model has not been studied in the case of multiple human blockage. Therefore, the purpose of this letter is to examine the accuracy of conducting cylinder model in predicting propagation loss due to multiple human blockage in short-range indoor links at 28 GHz, one of the most probable frequency bands allocated for 5G. To this end, firstly, a short-range indoor link was fully blocked by a human body, meanwhile, another human body around the link was approached to the link, and measurements were conducted. Then, GTD and DKED model were utilized to predict the propagation loss. In order to analyze the prediction accuracy of the models, measurement and simulation results were compared. As a result, for the first time in the literature, it has been observed that the prediction accuracy of multiple human body blockage is increased by using GTD-based model with experimental studies.

Keywords

5G, Perfectly conducting cylinder, Geometrical theory of diffraction, Double knife-edge diffraction, Propagation loss

Mükemmel İletken Silindir Modeli ile 28 GHz’de İç Mekân Linklerini Bloke Eden İnsanların Etkilerinin İrdelenmesi

Abstract

Literatürde, kısa mesafe iç mekân haberleşme linklerinde insan vücudu blokajının sebep olduğu kaybın tahmininde matematiksel olarak sade bir yapıya sahip olması sebebiyle Çift Bıçak Kenarlı Kırınım (ÇBKK) modeli sıklıkla kullanılmaktadır. Fakat modelde insan vücudu benzetimi için kullanılan dikdörtgensel ekran, insan vücudu fiziğini temsil etmek için yeterli olmayabilir. Bu durum, özellikle çoklu insan vücudu blokajı olması durumunda, modelin tahmin doğruluğunu olumsuz etkileyebilir. Öte yandan, insan vücudu benzetiminde Geometrik Kırınım Teorisi (GKT) temelli mükemmel iletken silindir modeli, literatürde sıklıkla kullan bir diğer modeldir. Ancak bu modelin, çoklu insan vücudu blokajı durumunda, yayılım kaybını tahmin etmedeki etkisi henüz çalışılmamıştır. Bu nedenle, sunulan bu kısa çalışmadaki amaç, iletken silindir modelinin, 5G için tahsis edilmesi en muhtemel frekans bantlarından biri olan 28 GHz’de, çoklu insan vücudu blokajının neden olduğu kısa mesafe iç mekân linklerindeki yayılım kaybını tahmin etmedeki doğruluğunu irdelemektir. Bu amaçla, öncelikle, kısa mesafe iç mekân linki bir insan vücudu ile tamamen bloklanmış; aynı anda, link yakınındaki başka bir insan vücudu linke yaklaştırılarak ölçümler yapılmıştır. Sonrasında, yayılım kaybını tahmin etmek için GKT ve ÇBKK modelinden faydalanılmıştır. Tahmin doğruluğu analizi için simülasyon ve ölçüm sonuçları karşılaştırılmıştır. Sonuç olarak deneysel çalışmalar ile literatürde ilk defa, çoklu insan vücudu blokajının GKT modeli ile tahmin doğruluğunun arttığı gözlemlenmiştir.

Keywords

5G, Mükemmel iletken silindir, Geometrik kırınım teorisi, Çift bıçak kenarlı kırınım, Yayılım kaybı

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