@article{du_mujumdar_ozdemir_ozturk_guvenc_sichitiu_dai_bhuyan_2022, title={60 GHz Outdoor Propagation Measurements and Analysis Using Facebook Terragraph Radios}, ISSN={["2164-2958"]}, DOI={10.1109/RWS53089.2022.9719957}, abstractNote={The high attenuation of millimeter-wave (mmWave) would significantly reduce the coverage areas, and hence it is critical to study the propagation characteristics of mmWave in multiple deployment scenarios. In this work, we investigated the propagation and scattering behavior of 60 GHz mmWave signals in outdoor environments at a travel distance of 98 m for an aerial link (rooftop to rooftop), and 147 m for a ground link (light-pole to light-pole). Measurements were carried out using Facebook Terragraph (TG) radios. Results include received power, path loss, signal-to-noise ratio (SNR), and root mean square (RMS) delay spread for all beamforming directions supported by the antenna array. Strong line-of-sight (LOS) propagation exists in both links. We also observed rich multipath components (MPCs) due to edge scatterings in the aerial link, while only LOS and ground reflection MPCs in the other link.}, journal={2022 IEEE RADIO AND WIRELESS SYMPOSIUM (RWS)}, author={Du, Kairui and Mujumdar, Omkar and Ozdemir, Ozgur and Ozturk, Ender and Guvenc, Ismail and Sichitiu, Mihail L. and Dai, Huaiyu and Bhuyan, Arupjyoti}, year={2022}, pages={156–159} }
 @article{ozturk_erden_du_anjinappa_ozdemir_guvenc_2022, title={Ray Tracing Analysis of Sub-6 GHz and mmWave Indoor Coverage with Reflecting Surfaces}, ISSN={["2164-2958"]}, DOI={10.1109/RWS53089.2022.9719917}, abstractNote={Indoor coverage and channel modelling is crucial for network planning purposes at mmWave bands. In this paper, we analyzed received power patterns and connectivity in an indoor office environment for sub-6 GHz and mmWave bands using ray tracing simulations and theoretical models over different scenarios. We discussed the effect of using metallic walls instead of regular drywall, base station (BS) location, and open/shut doors. Our results showed that ray tracing solutions are consistent with theoretical calculations, and using reflective walls significantly improves average received power and connectivity at mmWave bands, e.g., for the given floor plan, coverage increases from 86% to 97.5% at 60 GHz band.}, journal={2022 IEEE RADIO AND WIRELESS SYMPOSIUM (RWS)}, author={Ozturk, Ender and Erden, Fatih and Du, Kairui and Anjinappa, Chethan K. and Ozdemir, Ozgur and Guvenc, Ismail}, year={2022}, pages={160–163} }
 @article{du_ozdemir_erden_guvenc_2021, title={28 GHz Indoor and Outdoor Propagation Measurements and Analysis at a Regional Airport}, DOI={10.1109/PIMRC50174.2021.9569260}, abstractNote={In the upcoming 5G communication, the millimeter-wave (mmWave) technology will play an important role due to its large bandwidth and high data rate. However, mmWave frequencies have higher free-space path loss (FSPL) in line-of-sight (LOS) propagation compared to the currently used sub-6 GHz frequencies. What is more, in non-line-of-sight (NLOS) propagation, the attenuation of mmWave is larger compared to the lower frequencies, which can seriously degrade the performance. It is therefore necessary to investigate mmWave propagation characteristics for different deployment scenarios of interest, to understand coverage and rate performance in such scenarios. In this paper, we focus on 28 GHz wideband mmWave signal propagation characteristics at Johnston Regional Airport (JNX), a local airport near Raleigh, NC. To collect data, we use an NI PXI-based channel sounder at 28 GHz for indoor, outdoor, and indoor-to-outdoor scenarios. Results on LOS propagation, reflection, penetration, signal coverage, and multipath components (MPCs) show a lower indoor FSPL, a richer scattering, and a better coverage compared to outdoor. We also observe high indoor-to-outdoor propagation losses.}, journal={2021 IEEE 32ND ANNUAL INTERNATIONAL SYMPOSIUM ON PERSONAL, INDOOR AND MOBILE RADIO COMMUNICATIONS (PIMRC)}, author={Du, Kairui and Ozdemir, Ozgur and Erden, Fatih and Guvenc, Ismail}, year={2021} }
 @article{hosseini_khatun_guo_du_ozdemir_matolak_guvenc_mehrpouyan_2021, title={Attenuation of Several Common Building Materials: Millimeter-Wave Frequency Bands 28, 73, and 91 GHz}, volume={63}, ISSN={["1558-4143"]}, url={https://doi.org/10.1109/MAP.2020.3043445}, DOI={10.1109/MAP.2020.3043445}, abstractNote={Future cellular systems will make use of millimeter wave (mmWave) frequency bands. Many users in these bands are located indoors, i.e., inside buildings, homes, and offices. Typical building material attenuations in these high frequency ranges are of interest for link budget calculations. In this paper, we report on a collaborative measurement campaign to find the attenuation of several typical building materials in three potential mmWave bands (28, 73, 91 GHz). Using directional antennas, we took multiple measurements at multiple locations using narrow-band and wide-band signals, and averaged out residual small-scale fading effects. Materials include clear glass, drywall (plasterboard), plywood, acoustic ceiling tile, and cinder blocks. Specific attenuations range from approximately 0.5 dB/cm for ceiling tile at 28 GHz to approximately 19 dB/cm for clear glass at 91 GHz.}, number={6}, journal={IEEE ANTENNAS AND PROPAGATION MAGAZINE}, author={Hosseini, Nozhan and Khatun, Mahfuza and Guo, Changyu and Du, Kairui and Ozdemir, Ozgur and Matolak, David W. and Guvenc, Ismail and Mehrpouyan, Hani}, year={2021}, month={Dec}, pages={40–50} }
 @article{du_ozdemir_erden_guvenc_2021, title={Sub-Terahertz and mmWave Penetration Loss Measurements for Indoor Environments}, ISSN={["2164-7038"]}, DOI={10.1109/ICCWorkshops50388.2021.9473898}, abstractNote={Millimeter-wave (mmWave) and terahertz (THz) spectrum can support significantly higher data rates compared to lower frequency bands and hence are being actively considered for 5G wireless networks and beyond. These bands have high free-space path loss (FSPL) in line-of-sight (LOS) propagation due to their shorter wavelength. Moreover, in non-line-of-sight (NLOS) scenario, these two bands suffer higher penetration loss than lower frequency bands which could seriously affect the network coverage. It is therefore critical to study the NLOS penetration loss introduced by different building materials at mmWave and THz bands, to help establish link budgets for an accurate performance analysis in indoor environments. In this work, we measured the penetration loss and the attenuation of several common constructional materials at mmWave (28 and 39 GHz) and sub-THz (120 and 144 GHz) bands. Measurements were conducted using a channel sounder based on NI PXI platforms. Results show that the penetration loss changes extensively based on the frequency and the material properties, ranging from 0.401 dB for ceiling tile at 28 GHz, to 16.608 dB for plywood at 144 GHz. Ceiling tile has the lowest measured attenuation at 28 GHz, while clear glass has the highest attenuation of 27.633 dB/cm at 144 GHz. As expected, the penetration loss and attenuation increased with frequency for all the tested materials.}, journal={2021 IEEE INTERNATIONAL CONFERENCE ON COMMUNICATIONS WORKSHOPS (ICC WORKSHOPS)}, author={Du, Kairui and Ozdemir, Ozgur and Erden, Fatih and Guvenc, Ismail}, year={2021} }